Associations between socio-demographics, sexual knowledge and behaviour and sexually transmitted infections among reproductive-age women in Southeast Asia: Demographic Health Survey results

Abstract

Sexually Transmitted Infections (STIs) seriously affect population morbidity, mortality, and are a major public health problem worldwide. A cross-sectional study was conducted using the latest Demographic and Health Survey (DHS) data published between 2005 and 2022 for five Southeast Asian countries. The study’s focus was on STI risk factors in the DHS of Timor-Leste, Philippines, Indonesia, Myanmar, and Cambodia. The study included 139,062 women of reproductive age, aged 15 to 49 years, who reported whether they had experienced an STI or its symptoms and had comprehensive information on the variables of interest, including socio-demographics, sexual behaviour and knowledge. The report shows that the prevalence of STIs or symptoms of STIs in 5 Southeast Asian (SEA) countries included in the study is 11.6%, with the highest prevalence found in Cambodia, and the lowest in Philippines. Women aged 15–24 years in Indonesia (17.08%) and Philippines (9.81%), had a higher risk of STIs than those aged 25–49 years. In most studied countries of SEA (Cambodia, Indonesia and Myanmar), poorer women had higher risk of STIs. Also, in most SEA countries (Cambodia, Indonesia, and the Philippines), knowledge of STIs was significantly associated with having an STI in women aged 15–49 years. Sexual behaviour factors showed that acceptance of beating a wife for refusing to have sex with her husband was associated with STIs in all countries except Myanmar. The association between women’s characteristics in reproductive age including socio-demography, sexual knowledge and behaviour, and STIs or symptoms of STIs is varied in countries of SEA. STIs interventions can be tailored to the specific characteristics of women in each of the 5 countries of SEA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-025-21962-7.

Introduction

Sexually Transmitted Infections (STIs), involve the transmission of an organism between sexual partners through various routes of sexual contact, including oral, anal, or vaginal. STIs can be caused by infections with bacteria, viruses or parasites. The most common STIs include both curable (gonorrhea, chlamydia, syphilis, trichomonas) and treatable conditions (herpes viruses, human papillomavirus, human immunodeficiency virus). The likelihood of contracting these conditions depends on the prevalence of the disease, patient behavior, and underlying comorbidities [1] STIs have a major impact on sexual and reproductive health worldwide. They can cause acute urogenital conditions such as cervicitis, urethritis, vaginitis, and genital ulceration, and some etiologic agents also infect the rectum and pharynx. Chlamydia and gonorrhea can cause serious short-term and long-term complications, including pelvic inflammatory disease, ectopic pregnancy, infertility, chronic pelvic pain, and arthritis, and can be transmitted during pregnancy or childbirth [2]. Syphilis can cause neurological, cardiovascular, and dermatological disease in adults, as well as stillbirth, neonatal death, premature birth, or severe disability in babies. These four infections are involved in increasing the risk of human immunodeficiency virus (HIV) infection and transmission.

The World Health Organization (WHO) estimates that more than 1 million curable STIs are acquired every day worldwide in people aged 15–49 years, most of whom are asymptomatic. In 2020 there were an estimated 376 million new infections globally in people aged 15–49 years with 1 of 4 curable STIs: chlamydia (127 million cases), gonorrhea (87 million cases), syphilis (6 million cases), and trichomoniasis (156 million cases) [3–5]. In 2022, the WHO proposed a new global strategy to reduce the burden of STIs by 2030 [6]. This strategy suggests mechanisms to support improved STI service delivery through national-level policies, commitments, programming and monitoring are needed to operationalize, accelerate and monitor progress towards achieving the 2030 global STI strategy targets.

The prevalence of STIs is highest in low- and middle-income countries (LMICs). Planning, implementing prevention and control strategies in important regions and population groups requires a deeper understanding of STI epidemiological patterns. Additionally, improving sexual health education and STI surveillance for important areas and populations are crucial to lowering the burden of STIs [7]. There are several groups with varying needs that can take into consideration country-specific recommendations (see individual evaluations), including countries having major STI program limits to address, countries with urgent STI control requirements, small nations having the capacity to quickly ramp up STI control [8]. Sociodemographic markers and 3-month behavioral correlates of sexually transmitted infections (STIs) in a nonclinical cross-section of adolescent and young adult women. The participants’ type of residence (rural), age (17–18 and 21–23 years), years of sexual experience (> or = 2 years), frequency of hormonal contraceptive use (never and sometimes), perception that their sex partners had other concurrent sex partners, and the race or ethnicity of their last sex partner [9]. STIs are common but can be prevented with proper education and control using barriers. Moreover, people with STIs often experience stigma, stereotypes, vulnerability, shame, and gender-based violence (9) [10–12]. Intervention strategies are available, but are often hampered by low levels of knowledge and awareness, high rates of risk behaviors, and widespread stigma surrounding STIs in low and middle income countries, particularly in the Southeast Asia region where the prevalence of STIs is considered high [13].

Screening and early recognition of STIs is key to preventing disease spread, morbidity, and mortality [1].Identifying patterns of STI infection and identifying populations at greatest risk is important for prioritizing screening, targeting prevention strategies, and alleviating the burden of STIs [14]. For example, age at initiation of sexual relations, singledom, two or more sex partners and parity < 3 were identified as risk factors in South African women that most influence the prevalence and incidence rates of STIs [15]. Recent studies have identified early sexual initiation as a significant risk factor for STIs among women of reproductive age in Southeast Asia. In Indonesia, research indicates that early sexual activity among adolescent girls is associated with increased sexual risk behaviors, including multiple partners and inconsistent condom use, elevating the likelihood of STI exposure [16]. Similarly, a study encompassing Indonesia, Laos, Thailand, and Timor-Leste found that adolescents engaging in sexual activity before age 14 were more prone to multiple sexual partners and unprotected intercourse, further heightening STI risk [17]. In Vietnam, early sexual initiation among women has been linked to a higher number of lifetime sexual partners, correlating with an increased vulnerability to STIs [18]. Domestic violence, including wife beating, has emerged as a significant risk factor for STIs among reproductive-age women in Southeast Asia. In Thailand, research indicates that women experiencing intimate partner violence (IPV) are more than twice as likely to contract STIs compared to those not subjected to such violence [19]. Similarly, a study in Indonesia found that women who inject drugs and face IPV are at heightened risk for HIV due to increased sexual risk behaviors [20]. Qualitative research from Banda Aceh, Indonesia, further underscores the negative impact of domestic violence on women’s reproductive health, including unwanted pregnancies and STI transmission [21].

Little research has been conducted on the potential drivers of STI risk among women of reproductive age, a particularly vulnerable group in Southeast Asian countries, despite the importance of sexual autonomy in the prevention and control of sexual and reproductive health problems such as STIs. Therefore, this research analyses associations between socio-demographic factors, sexual knowledge and behaviours and STI risk in women in Southeast Asia.

Methods

Study design and data source

The study utilized data from Demographic and Health Surveys (DHS) published between 2005 and 2022 in 5 countries in Southeast Asia: Cambodia (2005–2006, 2010–2011, 2014, 2021–2022), Indonesia (2012 and 2017), Myanmar (2015 and 2016), The Philippines (2022), and Timor-Leste (2009–2010, 2016). We considered all countries in Southeast Asia and included those where datasets were available which included the variables of interest in this study. Data were extracted from the women’s file (Individual Recode file). In each country and survey a stratified two-stage cluster sampling technique was used to sample respondents for the survey. First stage, enumeration areas (EA) were generally drawn from census file. Second stage, in each EA selected, a sample of households was drawn from an updated list of households [22]. Further details of the approach used in each country can be found in published reports [23].

The DHS collected data on health indicators such as STIs or STI symptoms from respondents using a standardized questionnaire which was translated into the appropriate language in each setting. The study included a total of 139,062 (combining data from all included surveys from five Southeast Asia countries) women of reproductive age (15–49 years) who reported STIs or STI symptoms and had complete data on the variables of interest in this study. The description of the study sample can be found in Table 1. The dataset was obtained freely from the DHS database [23]. The weighted sample size ranged from 6,895 in Myanmar to 70,644 in Indonesia after excluding women who were missing information on STI or symptoms of STI, Sexual knowledge, and sexual knowledge, and sexual behaviour as well as women who were missing data on covariates variables.

Table 1.

STI history, demographic characteristics, sexual knowledge and sexual behaviour patterns among women of reproductive age in Southeast Asia

Variables	N = 139,062	%
Had an STI or symptoms of an STI in the past 12 months
No	122,924	88.4
Yes	16,138	11.6
Demographic Factors
Age groups
15–24 years	19,302	13.88
25–49 years	119,760	86.12
Place of residence
Urban	57,075	41.04
Rural	81,987	58.96
Highest educational level
No education	11,944	8.59
Primary	50,839	36.56
Secondary	59,848	43.04
Higher	16,431	11.82
Respondent’s occupation
Not working	47,256	33.98
Working	91,806	66.02
Wealth index
Poor	51,293	36.88
Middle	27,849	20.03
Rich	59,920	43.09
Sexually Knowledge Factors
Knowledge of contraception method
Knows no method, knows only folkloric & traditional	2,613	1.88
Knows modern	136,449	98.12
Ever heard of a sexually transmitted infection
No	20,151	14.49
Yes	118,911	85.51
Ever heard of AIDS
No	22,006	15.82
Yes	117,056	84.18
Heard about other STIs
No	75,700	54.44
Yes	63,362	45.56
Sexually Behaviour Factors
Current contraceptive use
Not using	59,382	42.7
Using	79,680	57.3
Age first sex
Min-14	7,092	5.1
15-max	131,970	94.9
Recent sexual activity
Active in last 4 months	111,035	79.85
Not active-postpartum	5,113	3.68
Not active-not postpartum	22,914	16.48
Beating justified if wife refuses to have sex with husband
No	124,711	89.68
Yes	14,351	10.32

Key variables and measurements

Outcome variable

The main outcome variables of interest for this study are women who had STI or symptoms of STI. We made a composite variable by combining those who answered yes to any of the questions about STIs as yes and those answered no to all of those questions as no. The items consisted of:

1. Women aged 15–49 who had an STI or STI symptom in the past 12 months.

2. Women aged 15–49 who had an abnormal (or bad smelling) genital discharge in the past 12 months.

3. Women aged 15–49 who had a genital sore or ulcer in the past 12 months.

Explanatory variables

Explanatory variables were sexual knowledge and sexual behaviour factors. Sexual knowledge factors were assessed using four items: knowledge of contraception methods, ever heard of a STI, ever heard of AIDS, and ever heard about other STIs. Knowledge of contraception methods were divided into knows no methods, knows only folkloric and traditional methods or knows modern methods. For each of the questions: ever heard of STI, ever heard of AIDS, and ever heard about other STIs respondents were divided into two categories (yes or no).

Sexual behaviour factors were indicated by four aspects: current contraceptive use, age at first sex, recent sexual activity, and beating justified if wife refuses to have sex with husband. Respondent who answered yes to any of the questions about current contraceptive methods were classified as “using” and those answered not using to the questions of current contraceptive methods as “not using”. Age at first sex was categorized into two categories (≤ 14-year-olds or ≥ 15-year-olds). We excluded respondents who never had sex and respondents who answered inconsistent and don’t know. Recent sexual activity was divided into three categories (active in the last 4 months, not active and postpartum, or not active and not postpartum). Responses to the question whether ‘women beating justified if wife refuses to have sex with husband’ was categorized into yes or no. Women who agree with justification for wife beating when refusing to have a sex were categorized as yes and women who disagree with justification for wife beating when refusing to have a sex were categorized as no.

Covariate variables included demographic factors: age groups (15–24 years or 25–49 years), place of residence (urban or rural), highest education level (no education, primary education, secondary education, or higher education), respondent’s occupation (not working or working), and wealth index or socioeconomic status. Wealth index was categorized into poor (poorer and poorest), middle, or rich (richer and richest).

Statistical analysis

We combined all data from the DHS survey in the selected country to increase the statistical power of the analysis and ensure stronger and more reliable results. By aggregating data from various time points, we are able to capture a broader representation of the population and reduce variability that may arise from smaller sample sizes in individual years. Our decision to combine data from multiple countries and time points was motivated by the need to examine broader regional patterns and associations. While we recognize the inherent challenges in pooling such data, our approach carefully considered the standardization of DHS methodologies and the temporal proximity of the surveys.

Data Analysis Strategy:

• Data Aggregation: The study pooled Demographic and Health Survey (DHS) datasets from five Southeast Asian countries, spanning 2005 to 2022. The rationale was to increase statistical power and generalizability while maintaining regional relevance.

• Descriptive Analysis: We began by examining the prevalence of STIs or STI symptoms, stratified by country and explanatory variables, to identify patterns in the data.

• Logistic Regression Analysis: Simple and Multiple logistic regression was used to estimate associations between socio-demographic factors, sexual knowledge, sexual behavior, and STI outcomes.

• Complex Sampling Design: All analyses accounted for the DHS complex survey design by incorporating weights, stratification, and clustering, ensuring accurate variance estimation.

Additionally, we made a composite variable by combining those who answered yes to any of the questions about STIs as yes and those answered no to all of those questions as no. Descriptive analysis first tabulated the distribution of women who had STI or symptoms of STI in five Southeast Asian countries. Then, the prevalence of STI or symptoms of STI were described disaggregated by countries and explanatory variables. Analysis of the association between sexual knowledge and sexual behaviour factors with STI or symptoms of STI were conducted using multiple logistic regression adjusting for DHS complex sampling design. Covariates (age, place of residence, highest education level, occupation and wealth index) were included in the logistic regression model. Adjusted Odds Ratios (AORs) with their respective 95% confidence intervals (CIs) were used to assess the associations between explanatory variables and STI or STI symptoms, adjusting for potential confounders. For the regression analysis, statistical significance was set at p < 0.05. In all the analyses, we applied the complex sample design to analyze the data. We carried out the data analysis using Stata.

Model-Building Strategy:

• Selection of Variables: Independent variables included sexual knowledge, sexual behavior, and socio-demographic covariates identified a priori based on literature and theoretical relevance.

• Univariate Analysis: Initially, univariate analyses were conducted to assess individual variable associations with the outcome.

• Multivariate Analysis: Adjusted odds ratios (AORs) with their respective 95% confidence intervals (CIs) were used to assess the associations between explanatory variables and STI or STI symptoms, adjusting for potential confounders. For the regression analysis, statistical significance was set at p < 0.05.

Ethic consideration

This study utilised secondary, de-identified, publicly available data sets. The original data collection activities were reviewed and approved by the ICF International Institutional Review Board, as well as Institutional Review Boards in each participating country. Details of these approval processes can be found at the DHS website [24].

Results

Table 1 showed that the proportion of respondents who had an STI or symptoms of an STI in the past 12 months across all studied countries in Southeast Asia was 11.6%. The prevalence of STIs were 13.70% in Cambodia, 12.30% in Indonesia, 8.49% in Timor-Leste, 7.99% in Myanmar, and 6.78% in Philippina. The majority of respondents were aged 24–59 years (86.12%), married or living with a partner (99.79%), and the largest proportions had secondary education (43.04%), and were wealthy (43.09%). More than half of the respondents lived in rural areas (58.96%) and were employed (66.02%). Almost all respondents knew about modern contraception (98.12%). Almost all respondents had heard about STIs (85.51%) and AIDS (84.18%). However, more than half had not heard about other STIs (54.44%). The age of first sexual intercourse was ≥ 15 years (94.9%). There were 57.3% of respondents who were currently using contraception, and 79.85% of respondents were sexually active in the last 4 months. Additionally, a total of 89.68% of respondents answered “no” to the question of whether it is justified to beat a wife if she refuses to have sex with her husband (Table 1).

Table 2 describes the incidence of STIs or STI symptoms across explanatory variables, as well as by country. STI incidence was highest in Indonesia followed by Cambodia. Rural dwellers and poorer participants were also more likely to have incurred an STI or STI symptoms overall, and in all countries except Myanmar and Timor-Leste. Associations between education level and STIs were mixed and showed no clear pattern. In all five countries, the proportion of women who had STI or symptoms of STI was higher among those who knew modern contraception methods, and those who had ever heard of STIs. The proportion of women who had STI or symptoms of STI was higher among those who had ever heard of AIDS except in Cambodia. Similarly, the proportion of women who had STI or symptoms of STI was higher among those who had ever heard of other STIs except in Cambodia and Indonesia. The proportion of women who had STI or STI symptoms was higher among those currently using contraception except in Indonesia. Similarly, the proportion of women who had STI or symptoms of STI was higher among those who had been sexually active when aged less than 14 years old in Myanmar, The Philippines, and Timor-Leste. Additionally, the proportion of women who had STI or symptoms of STI was higher among those who had recent sexual activity in the last 4 months in Cambodia and Timor-Leste. In all five countries, the proportion of women who had STI or symptoms of STI was lower among women with higher disagreement with justification for wife beating (Table 2).

Table 2.

Prevalence of STI or symptoms of STI disaggregated by countries and explanatory variables

Variables	Southeast Asia = 139,062				Cambodia = 37,031				Indonesia = 70,644				Myanmar = 6,895				The Philippines = 15,001				Timor-Leste = 9,491
	Had STI				Had STI				Had STI				Had STI				Had STI				Had STI
	N	no	yes	p value	N	no	yes	p value	N	no	yes	p value	N	no	yes	p value	N	no	yes	p value	N	no	yes	p value
		%	%			%	%			%	%			%	%			%	%			%	%
Demographic Factors
Age groups				< 0.001				0.87				< 0.001				0.161				< 0.001				0.406
15–24 years	19,302	85.66	14.34		6,189	86.39	13.61		9,002	82.92	17.08		938	90.60	9.40		1,586	90.19	9.81		1,587	90.96	9.04
25–49 years	119,760	88.84	11.16		30,842	86.29	13.71		61,642	88.4	11.6		5,957	92.23	7.77		13,415	93.58	6.42		7,904	91.62	8.38
Place of residence				< 0.001				0.188				< 0.001				0.041				0.01				0.025
Urban	57,075	89.13	10.87		9,152	86.93	13.07		35,533	88.45	11.55		1,832	90.29	9.71		8,097	94.06	5.94		2,460	90.11	9.89
Rural	81,987	87.88	12.12		27,878	86.1	13.9		35,111	86.93	13.07		5,063	92.63	7.37		6,904	92.24	7.76		7,031	92	8
Highest educational level				< 0.001				< 0.001				< 0.001				0.042				0.56				0.372
No education	11,944	88.31	11.69		5,954	84.76	15.24		1,612	89.92	10.08		943	92.84	7.16		133	96.09	3.91		3,303	92.32	7.68
Primary	50,839	88.02	11.98		19,142	86.18	13.82		24,047	88.03	11.97		3,267	92.96	7.04		2,094	93.27	6.73		2,289	91.53	8.47
Secondary	59,848	87.90	12.10		10,810	86.87	13.13		36,140	86.75	13.25		2,105	90.82	9.18		7,328	92.95	7.05		3,465	90.75	9.25
Higher	16,431	91.4	8.6		1,125	91.17	8.83		8,845	90.28	9.72		580	89.59	10.41		5,446	93.49	6.51		434	91.27	8.73
Respondent’s occupation				< 0.001				0.882				0.262				0.926				0.413				< 0.001
Not working	47,256	89.16	10.84		6,679	86.38	13.62		26,987	87.96	12.04		2,032	91.96	8.04		6,118	93.51	6.49		5,441	92.62	7.38
Working	91,806	88	12		30,352	86.29	13.71		43,657	87.54	12.46		4,863	92.03	7.97		8,884	93.02	6.98		4,050	90.01	9.99
Wealth index				< 0.001				< 0.001				< 0.001				0.391				0.156				0.549
Poor	51,293	87.03	12.97		14,213	83.94	16.06		24,728	86.26	13.74		2,796	91.81	8.19		6,029	92.52	7.48		3,528	91.67	8.33
Middle	27,849	88.15	11.85		7,287	86.55	13.45		14,164	86.72	13.28		1,406	93.1	6.9		3,088	93.85	6.15		1,904	92.06	7.94
Rich	59,920	89.68	10.32		15,531	88.35	11.65		31,751	89.25	10.75		2,693	91.65	8.35		5,885	93.61	6.39		4,059	91.11	8.89
Sexual Knowledge Factors
Knowledge of contraception method				< 0.001				0.324				0.249				0.713				0.137				< 0.001
Knows no method, knows only folkloric & traditional	2,613	93.51	6.49		88	90.42	9.58		413	90.1	9.9		76	93.06	6.94		36	97.94	2.06		1,999	94.28	5.72
Knows modern	136,449	88.30	11.70		36,943	86.29	13.71		70,230	87.68	12.32		6,819	92	8		14,965	93.21	6.79		7,492	90.77	9.23
Ever heard of a sexually transmitted infection				< 0.001				0.306				0.015				0.113				0.013				< 0.001
No	20,151	90.38	9.62		507	88.15	11.85		13,027	88.6	11.4		469	94.07	5.93		711	96.24	3.76		5,438	93.77	6.23
Yes	118,911	88.06	11.94		36,524	86.28	13.72		57,617	87.49	12.51		6,426	91.86	8.14		14,291	93.07	6.93		4,054	88.48	11.52
Ever heard of AIDS								0.631				0.019				0.147				0.229				< 0.001
No	22,006	89.87	10.13		677	85.59	14.41		14,196	88.51	11.49		489	93.8	6.2		851	94.58	5.42		5,792	92.67	7.33
Yes	117,056	88.12	11.88		36,353	86.32	13.68		56,448	87.49	12.51		6,406	91.87	8.13		14,150	93.14	6.86		3,699	89.69	10.31
Heard about other STIs				0.815				0.612				< 0.001				0.033				0.846				< 0.001
No	75,700	88.37	11.63		8,489	86.07	13.93		45,008	86.36	13.64		5,212	92.51	7.49		9,578	93.26	6.74		7,413	93.94	6.06
Yes	63,362	88.43	11.57		28,542	86.37	13.63		25,636	90.05	9.95		1,683	90.47	9.53		5,423	93.14	6.86		2,078	82.83	17.17
Sexual Behaviour Factors
Current contraception use				0.001				< 0.001				0.144				0.03				0.822				< 0.001
Not using	59,382	88.84	11.16		16,630	87.33	12.67		25,994	87.37	12.63		3,244	92.87	7.13		6,252	93.3	6.7		1,945	94.19	5.81
Using	79,680	88.06	11.94		20,401	85.47	14.53		44,650	87.89	12.11		3,651	91.24	8.76		8,749	93.16	6.84		7,546	90.82	9.18
Age first sex				0.337				0.554				0.026				0.621				0.904				0.003
Min-14	7,092	88.89	11.11		917	87.1	12.9		4,985	89.07	10.93		165	90.87	9.13		455	93.06	6.94		570	86.21	13.79
15-max	131,970	88.37	11.63		36,114	86.28	13.72		65,659	87.59	12.41		6,730	92.04	7.96		14,547	93.22	6.78		8,921	91.85	8.15
Recent sexual activity				< 0.001				0.503				0.002				0.099				0.001				0.04
Active in last 4 months	111,035	88.18	11.82		29,705	86.17	13.83		57,787	87.59	12.41		5,409	92.16	7.84		11,136	92.83	7.17		6,997	91.08	8.92
Not active-postpartum	5,113	87.71	12.29		1,650	86.9	13.1		1,871	85.02	14.98		220	95.49	4.51		483	90.12	9.88		889	91.67	8.33
Not active-not postpartum	22,914	89.61	10.39		5,676	86.81	13.19		10,985	88.74	11.26		1,266	90.76	9.24		3,382	94.94	5.06		1,605	93.3	6.7
Beating justified if wife refuses to have sex with husband				< 0.001				0.005				< 0.001				0.18				0.299				< 0.001
No	124,711	88.71	11.29		32,104	86.57	13.43		65,654	88.05	11.95		6,076	92.21	7.79		14,840	93.25	6.75		6,036	92.57	7.43
Yes	14,351	85.66	14.34		4,927	84.55	15.45		4,989	83.01	16.99		819	90.55	9.45		161	90.61	9.39		3,455	89.66	10.34

Unadjusted analysis for sexual knowledge factors (see supplementary file) showed that knowledge of contraception methods had a significant positive association with women who had STIs in Timor-Leste; ever having heard of STIs was an individually significant factor positively associated with women who had STIs in Indonesia, The Philippines, and Timor-Leste; ever having heard of AIDS was an individually significant factor positively associated with women who had STI in Indonesia and Timor-Leste; while ever heard of other STIs was individually significant factor that were positively associated with women who had STI in Indonesia, Myanmar, and Timor-Leste. Additionally, current contraceptive use was significantly positively associated with women who had STI in Cambodia, Myanmar, and Timor-Leste; age at first sex was individually significant factor that were positively associated with women who had STI in Indonesia (older age at first sex) and Timor-Leste (younger age at first sex); recent sexual activity was an individually significant factor that was positively associated with women who had STI in Indonesia, The Philippines, and Timor-Leste; while beating justified if wife refuses to have sex with husband were positively associated with women who had STI in Cambodia, Indonesia, The Philippines, and Timor-Leste (supplementary file).

In fully adjusted models shown in Table 3, people aged 15–24 years in Southeast Asian overall, and in Indonesia and the Philippines, had higher odds of STI or symptoms of STI than those aged 25–49 years. Rural residence was associated with lower odds of experiencing STI or symptoms of STI in Cambodia, but higher odds in the Philippines, and no association was found in other settings. Lower education levels were associated with lower likelihood of experiencing STI or symptoms of STI overall, and in Cambodia and Indonesia. Being employed was associated with higher STI risk overall and in Indonesia and Timor-Leste. Poorer groups were also at higher risk of getting STIs overall, and in Cambodia, Indonesia and Myanmar.

Table 3.

Adjusted odds ratios (AOR) and 95% confidence interval (CI) for the association between demographic, sexual knowledge and sexual behaviour factors with had an STI or symptoms of an STI in the past 12 months

Had an STI or symptoms of an STI in the past 12 months	Southeast Asia		Cambodia		Indonesia		Myanmar		The Philippines		Timor-Leste
	AOR	95% CI	AOR	95% CI	AOR	95% CI	AOR	95% CI	AOR	95% CI	AOR	95% CI
		Lower-Upper		Lower-Upper		Lower-Upper		Lower-Upper		Lower-Upper		Lower-Upper
Demographic Factors
Age groups
15–24 years	1.30***	1.22–1.38	1.01	0.91–1.13	1.42***	1.30–1.56	1.22	0.90–1.66	1.56***	1.21–2.00	1.19	0.97–1.45
25–49 years	Ref		Ref		Ref		Ref		Ref		Ref
Place of residence
Urban	Ref		Ref		Ref		Ref		Ref		Ref
Rural	1.00	0.94–1.07	0.86*	0.76–0.97	1.03	0.94–1.12	0.77	0.55–1.08	1.33*	1.06–1.66	0.88	0.69–1.12
Highest educational level
No education	1.35***	1.20–1.52	1.56**	1.17–2.08	0.91	0.70–1.19	0.72	0.41–1.26	0.68	0.29–1.60	1.38	0.77–2.45
Primary	1.33***	1.21–1.46	1.44**	1.09–1.91	1.04	0.91–1.18	0.68	0.43–1.07	1.01	0.74–1.37	1.40	0.78–2.49
Secondary	1.37***	1.25–1.49	1.48**	1.12–1.96	1.19**	1.06–1.32	0.89	0.56–1.42	1.03	0.82–1.30	1.34	0.78–2.32
Higher	Ref		Ref		Ref		Ref		Ref		Ref
Respondent’s occupation
Not working	Ref		Ref		Ref		Ref		Ref		Ref
Working	1.14***	1.08–1.20	1.00	0.90–1.11	1.12**	1.04–1.20	1.04	0.83–1.29	1.14	0.94–1.38	1.25*	1.04–1.52
Wealth index
Poor	1.26***	1.19–1.34	1.52***	1.37–1.69	1.24***	1.13–1.35	1.35*	1.03–1.79	1.07	0.82–1.40	1.24	0.97–1.59
Middle	1.12***	1.05–1.20	1.22**	1.08–1.38	1.18***	1.08–1.29	1.04	0.76–1.41	0.91	0.70–1.20	1.12	0.87–1.44
Rich	Ref		Ref		Ref		Ref		Ref		Ref
Sexual Knowledge Factors
Knowledge of contraception method
Knows no method, knows only folkloric & traditional	0.57***	0.47–0.69	0.72	0.31–1.65	0.76	0.50–1.16	1.17	0.49–2.78	0.38	0.06–2.32	0.78*	0.62–0.97
Knows modern	Ref		Ref		Ref		Ref		Ref		Ref
Ever heard of a sexually transmitted infection
No	0.57***	0.47–0.68	0.49*	0.28–0.87	0.61***	0.47–0.79	0.55	0.11–2.81	0.23**	0.10–0.56	0.81	0.53–1.23
Yes	Ref		Ref		Ref		Ref		Ref		Ref
Ever heard of AIDS
No	1.30**	1.11–1.54	1.60*	1.05–2.43	1.26	0.98–1.61	1.42	0.30–6.60	2.10*	1.04–4.24	1.32	0.92–1.90
Yes	Ref		Ref		Ref		Ref		Ref		Ref
Heard about other STIs
No	1.05	0.99–1.11	0.98	0.89–1.09	1.45***	1.33–1.57	0.86	0.67–1.12	1.03	0.85–1.25	0.32***		0.23–0.43
Yes	Ref		Ref		Ref		Ref		Ref		Ref
Sexual Behaviour Factors
Current contraception use
Not using	0.95*	0.90–0.99	0.83***	0.77–0.90	1.06	0.99–1.14	0.81*	0.65–1.00	1.06	0.88–1.28	0.99		0.82–1.21
Using	Ref		Ref		Ref		Ref		Ref		Ref
Age first sex
Min-14	0.95	0.86–1.06	0.91	0.72–1.14	0.89	0.78–1.01	1.19	0.66–2.16	0.96	0.63–1.44	1.72**		1.19–2.49
15-max	Ref		Ref		Ref		Ref		Ref		Ref
Recent sexual activity
Active in last 4 months	Ref		Ref		Ref		Ref		Ref		Ref
Not active-postpartum	1.05	0.93–1.17	1.02	0.85–1.23	1.12	0.92–1.35	0.60	0.28–1.29	1.34	0.86–2.08	0.95		0.71–1.27
Not active-not postpartum	0.89***	0.84–0.95	0.99	0.89–1.11	0.89*	0.82–0.97	1.28	0.99–1.67	0.69**	0.54–0.87	0.81		0.63–1.04
Beating justified if wife refuses to have sex with husband
No	Ref		Ref		Ref		Ref		Ref		Ref
Yes	1.31***	1.22–1.41	1.13*	1.01–1.28	1.42***	1.28–1.59	1.33	0.97–1.83	0.06***	0.04–0.08	1.36**		1.12–1.65

*** p < 0.001, ** p < 0.01, * p < 0.05

Lack of knowledge of modern contraception methods was associated with lower risk of STI or symptom of STI in Timor-Leste, and overall. Women who knew no method, knew only folkloric & traditional had 22% lower odds of having STI or symptoms of an STI compared with women who knew modern methods. After adjustment for covariates, having never heard of STIs had a significantly positive association with women who had STI or symptoms of STI in Cambodia, Indonesia, and The Philippines (Table 3). In Cambodia, women who never heard of STI had 61% lower odds of having STI or symptoms of STI compared with women who ever heard of STI. In Indonesia, women who never heard of STI had 39% lower odds of having STI or symptoms of STI compared with women who ever heard STI. In The Philippines, women who never heard of STI had 77% lower odds of having STI or symptoms of STI compared with women who ever heard STI.

Having ever heard of AIDS was significantly positively associated with women who had STI or symptoms of STI in Cambodia and The Philippines after adjustment for covariates (Table 3). In Cambodia, women who never heard AIDS had 60% greater odds of having STI or symptoms of STI compared with women who ever heard AIDS. In the Philippines, women who never heard AIDS had 110% greater odds of having STI or symptoms of STI compared with women who ever heard AIDS.

Having heard about other STIs was significantly positively associated with women who had STI or symptoms of STI in Indonesia and The Timor-Leste after adjustment for covariates (Table 3). In Indonesia, women who had never heard other STIs had 45% greater odds of having STI or symptoms of STI compared with women who ever heard other STIs. While, in Timor-Leste, women who never heard other STIs had 68% lower odds of having STI or symptoms of STI compared with women who ever heard other STIs.

Current contraception methods were significantly positively associated with women who had STI or symptoms of STI in Cambodia and Myanmar after adjustment for covariates (Table 3). Women who did not use current contraception had 17% and 19% lower odds of having STI or symptoms of STI compared with women who were using current contraception in Cambodia and Myanmar respectively. In Timor-Leste, women who had first sexual activity before 15 years old had 78% greater odds of having STI or symptoms of STI compared with women who had first sexual activity 15-or more-year-olds.

Believing that beating is justified if the wife refuses to have sex with husband was significantly positively associated with women who had STI or symptoms of STI in all countries except in The Philippines. In Cambodia, women agreeing with justification for wife beating had 23% greater odds of having STI or symptoms of STI, in Indonesia, 42% greater odds, and in Timor-Leste, 36% greater odds. Whereas, In the Philippines, women’s agreement with justification for wife beating had 94% lower odds of having STI or symptoms of STI compared with women’s disagreement with justification for wife beating.

Discussion

Few studies of STI prevalence by women’s socio-demographic characteristics, sexual knowledge and sexual behaviours have been conducted in the low- and middle-income countries (LMIC) in South East Asia (SEA). Our study found that STIs or symptoms of STIs are common in SEA including Cambodia, Indonesia, Myanmar, Philippines and Timor-Leste based on our analysis of multiple nationally representative surveys. Overall, 11.6% of women had experienced them in the last 12 months in SEA for 5 countries included in the study. However, prevalence varied widely across the region with Cambodia having the highest, followed by Indonesia, Timor-Leste, Myanmar and Philippines with the lowest rates. Numerous factors, including poverty, high rates of STIs, the widespread use of female sex workers (SWs), and a highly mobile workforce, may be responsible for this [25]. Additionally, the use of drugs, especially amphetamine-type stimulants (ATS), may become a potentially serious issue for SWs in Cambodia and throughout Asia. The utilization of ATS was linked to the occurrence of incident STIs [26]. Epidemiological assessments of STI prevalence in the region are rare and our results provide much needed evidence for developing health policy responses according to socio-demographic, sexual knowledge and behavior as variables studied.

Our findings showed women aged 15–24 years in Indonesia (17.08%) and Philippines (9.81%), had a higher risk of STIs than those aged 25–49 years. Younger women in Indonesia and Philippines were more likely to experience infections than other SEA countries. People between the ages of 15 and 24 have the highest reported incidence of STIs worldwide; they account for up to 60% of new infections and half of all HIV-positive individuals [27]. In US, STIs particularly noticeable is the rise among teenagers (15–24 years old), one in four sexually active teenage girls are thought to have a STI, most frequently an infection with the human papillomavirus (HPV) or Chlamydia trachomatis (CT) [28]. The rising trend in gonorrhoea diagnoses was reflected across all age groups in this period but rates almost doubled for 15-to-24-years-olds (a 91.7% increase, from 16,191 to 31,037) [29]. STIs continue to have the biggest effects on young people between the ages of 15 and 24; gay, bisexual and other men who have sex with men (GBMSM); and certain minority ethnic groups [30]. However, young people in the age group 15 to 24 years are the most likely to be diagnosed with the most common types of STIs, not only in developing but also in developed countries. Women who live in rural areas have a lower risk of experiencing STIs or symptoms of STIs compared to those who live in urban areas in Cambodia, unlike in the Philippines, where those who live in villages are more at risk than those in cities. In terms of the number of people affected (cases), metropolitan and urban areas typically bear the brunt of STI or drug use [31]. On the other hand, according to several epidemiological studies, STI rates are higher in some rural communities than in their urban counterparts [32–34]. Many groups in Southeast Asia have linked drug use, especially ATS, to incident STI and HIV as well as risky sexual and drug-related behaviors [35]. Drug use in general, and possibly more so for users of illegal stimulants like methamphetamine (which are disproportionately reported in rural areas), increases the risk of contracting STIs. Otherwise, there are fewer rural health services available, they are often harder to access, and they can stigmatize people who need them. These could be a factor in the underreporting of STIs [31]. Rural communities differ significantly from small metropolitan areas in terms of risk, services, and accessibility. Most STI interventions and programs are created in urban settings, and it is not always clear or equally effective to translate them to rural ones [31]. Understanding these dynamics is crucial to the planning, execution, and success of STI control initiatives.

In this study those who work are at higher risk than those who do not work as shown in Indonesia and Timor-Leste. This is a similar finding to another study in Uganda which found the likelihood of reporting a positive STI was significantly higher for female adolescents who worked but did not receive compensation, were self-employed in agriculture, and were performed manual labour, were regardless of skill level [36]. Nevertheless, other findings in Indonesia and Saudi Arabia, STIs also was found dominantly in housewives [37, 38]. Regarding with wealth index, the poorer the risk of getting STIs or symptoms of STIs in Cambodia and Indonesia. While, the risk of STIs or symptoms of STIs was significant different only between poor and rich group in Myanmar. STI symptoms were less common in women in the richest quintile and in couples who made decisions together [39]. Previous data showed that middle and higher Socio-economic status (SES), as measured by wealth index quintile, had inverse effects on STI risk with middle SES posing the highest risk and higher SES being protective [40].

The correlation between aged 15–24 years old and a higher risk of STIs may be due to knowledge level, attitude and practices about risky sexual behavior, and other problems relating to reproductive health. Disseminating information on preventive measures would result from knowledge of teenage sexual habits, particularly risk behavior associated with unprotected intercourse [41]. Our finding was found the correlation between educational level and STIs, the highest education level the lowest risk of STIs. In Cambodia, the lower the education, the higher the risk of experiencing STIs or symptoms of STIs, whereas in Indonesia, the higher risk of STIs or symptoms of STIs was found in the secondary education level compared to lower education level. The association between STIs risk and education has been thoroughly examined in the adolescent population. The necessity of comprehensive sex education programs and the significance of comprehending teenage sexuality have been clarified by a systematic review [42]. Insufficient sex education had a negative effect on participants’ awareness and knowledge of contraception, indicating that abstinence-only sex education is ineffective in lowering the number of unwanted pregnancies and abortions in the US because of the medical misinformation these programs spread [43]. However, research on young adults frequently assumes that education shields one from risk outcomes or downplays the influence of important social determinants like education on participation in risky behaviours and STI diagnosis [44, 45].

Numerous research investigations have revealed that young people, who are the most susceptible to contracting STIs, have differing degrees of awareness regarding these infections. Related with contraceptive knowledge, our findings suggest that in Timor-Leste, those who are either unaware of contraceptive methods or only familiar with traditional methods have a lower risk of STIs or symptoms of STIs compared to those knowledgeable about modern methods. In Timor-Leste, women who rely on traditional methods or are unaware of contraceptives tend to be more cautious in their sexual activities, especially for young and unmarried people who were identified fear and shyness in approaching a healthcare provider or visiting a health centre, which might indirectly reduce their risk of STIs or symptoms of STIs [46]. As in Indonesia, cultural factors, such as the taboo around discussing contraception, lead many women of reproductive age to avoid or less frequently engage in risky sexual behaviours, further lowering their risk of STIs [47]. Interestingly, our findings indicate that individuals in Cambodia, Indonesia, and the Philippines who have never heard of STIs show a lower risk of contracting these infections compared to those who are aware of them. Individuals without knowledge of STIs might be less likely to seek medical care or report symptoms, potentially skewing the data. Additionally, healthcare workers may engage in stigmatization and discrimination, causing individuals to avoid seeking treatment and resulting in undetected cases [46]. Our findings reveal that individuals in Cambodia and the Philippines who have never heard of AIDS exhibit a higher risk of STIs or symptoms of STIs. Those with good knowledge about AIDS are more likely to undergo HIV testing. These consistent findings underscore the importance of effective AIDS education. Awareness of HIV is closely linked to higher rates of HIV testing, which helps reduce the risk of HIV [48]. This study found that a lack of awareness about STIs increases risk in Indonesia, whereas it decreases risk in Timor-Leste. In Indonesia, cultural taboos surrounding sexual issues can hinder comprehensive sex education. This results in a lack of crucial information about STIs and self-protection. This gap in education increases vulnerability to STIs and sexual harassment. Therefore, implementing early and comprehensive sex education is essential to equip young people with the knowledge needed to effectively manage STI risks [49]. The DHS data matchmaking process uses sexual knowledge and behavior with limited variables in five of the study’s countries, so its relevance is also limited. In addition, young people have higher levels of emotional instability (for example, depressive symptoms) and impulsivity than the older group [50]. This suggests screening activities are particularly needed for this group, and that education regarding STIs as well as their actual practices is very important in younger women.

Regarding current contraception use, a lack of contraception use is associated with lower STIs or symptoms of STIs rates in Cambodia and Myanmar. In Myanmar, contraception use is often linked to married couples or those who are sexually active. This association reflects more conservative sexual behaviours. Evidence shows that sexually active youth, typically those who are married, are significantly more likely to use modern contraception compared to their unmarried counterparts. Therefore, lower contraceptive use in certain populations may indicate reduced sexual activity and contribute to lower STI prevalence [51]. Having sexual intercourse for the first time before the age of 14 increases the risk of STIs or symptoms of STIs in Timor-Leste. As the age of first sexual contact decreased, the likelihood of contracting STIs rose [52, 53]. By the end of childhood, innate and adaptive immune responses similar to those in adults become normal, levels of B and T memory cells approach those of adults, and the production of naïve T cells by the thymus decreases substantially as immune memory against childhood infectious diseases develops. However, the immune system is not yet fully mature, making it still highly vulnerable to infections, including STIs [54].

Our study shows that being sexually inactive lowers the risk of STIs or symptoms of STIs in Indonesia and the Philippines compared to those who are sexually active over the past 4 months. The risk of contracting STIs or symptoms of STIs depends on exposure to pathogens through sexual activity. In Indonesia, HIV/AIDS transmission often occurs among groups with multiple sexual partners and inconsistent condom use, which increases pathogen exposure. This evidence supports the argument that the risk of STIs or symptoms of STIs is lower for individuals who are sexually inactive because they are not exposed to these pathogens. In other words, a lack of sexual activity significantly reduces the risk of STI infection [55]. This study shows that experiences of sexual beating are associated with an increased risk of STIs or symptoms of STIs in Cambodia, Indonesia, and Timor Leste, but in the Philippines, the same experiences are linked to a decreased risk. Women who have recently experienced abuse are much more likely to contract STIs than women who have not experienced abuse [56–58]. Poverty and STI/HIV have a complex relationship; in certain contexts, wealth may also increase the risk of STI/HIV [59], and microfinance interventions may increase violence against women if they are not planned with cultural sensitivity [60]. Furthermore, when girls live in unfavorable sociocultural and economic circumstances, these vulnerabilities may be made worse [61].

The Region’s STI epidemiology is still incredibly diverse [62–64]. While much higher and more variable rates are reported elsewhere, Sri Lanka and Thailand have maintained very low STI incidence and prevalence over several decades. Recent certifications of having eradicated mother-to-child transmission of HIV and syphilis have been given to Thailand and the Maldives, and Sri Lanka is getting ready for validation of the same [65]. Universal Health Coverage (UHC) is crucial for addressing these inequalities by ensuring equitable and high-quality healthcare access for everyone [66]. Cambodia has the National Center for HIV/AIDS, Dermatology and STD (NCHADS), which runs the STI Control Program. According to the Strategic Plan for HIV and STI Prevention and Care in the Health Sector 2021–2025, this program specifically targets STI prevention, diagnosis, and treatment within the broader framework of NCHADS, focusing on both STIs and HIV/AIDS [67]. In the Philippines, the National STI/HIV Surveillance and Strategic Information Program is in place. This program monitors STI trends, provides targeted interventions, and integrates STI prevention and control within broader surveillance efforts [68]. Indonesia is improving triple elimination program particularly for STIs HIV and syphilis screening in pregnant women to reduce the cases [69]. In most other countries, epidemiological assessments are limited by insufficient data on STIs, which impedes control efforts.

There are wide regional variations in the way the current program responds to STIs. Thailand and Sri Lanka have consistently provided funding and commitments for many years. In a STI control and HIV prevention demonstration project, Myanmar has shown early success, achieving 100% targeted condom promotion and halving the prevalence of syphilis. Syphilis rates are declining in Bangladesh, according to limited data, primarily as a result of STI services, condom promotion, awareness-raising, and sex worker mobilization. This regional report emphasizes the state of affairs, the response to it, and the pressing need to move quickly to put STI control back on the public health agenda [70]. The global health-sector strategy on STIs (2016–2021) of the World Health Organization (WHO) has set targets for 90% reductions in the incidence of gonorrhoeae (Neisseria gonorrhoeae) and syphilis (Treponema pallidum) infections between 2018 and 2030 [64].

There are intervention strategies available, but they are frequently hindered by high rates of risky behaviours adopted, low levels of knowledge and awareness, and a pervasive stigma surrounding STIs. Therefore, increasing people’s understanding of STIs and their impact on their perceptions, attitudes, risky behaviours, and knowledge is essential to global intervention, prevention, and control strategies. However, there is a dearth of data regarding risky behaviours, perception, knowledge, awareness, and attitude among developing nations, especially in the SEA region where STI prevalence is thought to be high.

Strengths and limitations

This study utilised large nationally representative surveys in Southeast Asian countries at a variety of levels of socio-economic development, and with differing cultures. It was therefore able to identify many important risk factors for STIs in the region include some that are novel to this study. Our study’s key finding was that younger people (15–24 years old) were more likely to contract STIs; as a result, the government should carefully examine policies for screening and education programs for this demographic, particularly with regard to STIs and reproductive health in general. However, there are some important limitations. Firstly, all associations are measured in a cross-sectional design. This means we cannot identify causative factors for STI infections. Also, the combination of data across different time points for most countries may mask trends in risk factor-infection associations. As well, analyses of the association between sexual knowledge and behavioural factors and STIs or STI symptoms found limited data. Due to the lack of health national data surveys, this study could not investigate all countries in Southeast Asia. Finally, the data available did not allow us to analyse which specific STIs were being experienced by the participants.

Conclusions

The results of this study reveal important information on patterns of STI risk among women of childbearing age in Southeast Asia. These results can give key setting-specific information which will inform the planning of health system responses. A key finding was that prevalence varied widely across countries, and some risk factors were more important in some setting than others. This emphasises the need for the collection of detailed local data for local responses. Increasing understanding of STIs and their impact on their perceptions, attitudes, risky behaviors, and knowledge is essential to global intervention, prevention, and control strategies in particular in young women aged 15–24 years old.

Electronic supplementary material

Below is the link to the electronic supplementary material.

Author contributions

LNY, EA contributed in the conceptualization, study design, data analysis, data interpretation, and article manuscript drafting. EQ, YG contributed in the conceptualization or design, validation, and data interpretation. MIL contributed in the conceptualization or design, and data interpretation. MK contributed in the study design, data interpretation, and article manuscript drafting. All authors read and approved the final manuscript.

Funding

Not applicable.

Data availability

The datasets are available for free after a registration in the website of DHS. The data can be accessed at https://dhsprogram.com/Data/.

Declarations

Ethical approval

Procedures and questionnaires for standard DHS surveys have been reviewed and approved by ICF Institutional Review Board (IRB). Additionally, country-specific DHS survey protocols are reviewed by the ICF IRB and typically by an IRB in the host country.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.