The relationship of body mass index with sexual function and marital satisfaction in reproductive-age women: A cross-sectional study in Iran

Abstract

BACKGROUND:

Obesity is a global issue and has negative effects on various aspects of life, including physical and psychosocial health, which leads to a reduced quality of life. The present study was conducted to investigate the relationships between body mass index, sexual function, and marital satisfaction in reproductive-aged women.

MATERIALS AND METHODS:

The present research was a cross-sectional study that was conducted using socio-demographic and obstetric checklist, and questionnaires, including the Female Sexual Function Inventory (FSFI) and Enrich Marital satisfaction questionnaire as well as using a weight scale and stadiometer to measure height on 350 women of reproductive age referred to health centers during 2022 in Babol, Iran. The data were analyzed using SPSS 25, and Chi-square tests and ANOVA were performed.

RESULTS:

The results showed that there was a significant difference in the sexual function of women with a normal body mass index compared to overweight (P = 0.034) and obese (P < 0.001) women. Additionally, a significant correlation was observed between sexual function and marital satisfaction among the research participants (r = 0.109, P = 0.041).

CONCLUSION:

Considering the relationships among body mass index, sexual function, and marital satisfaction, it is important to screen women with higher body mass indices for sexual function and marital satisfaction and to offer suitable counseling and approaches to identify and address all related factors in addition to weight management recommendations.

Introduction

The global prevalence of obesity has nearly tripled since 1975, with an estimated 38% of the world’s population projected to be obese by 2030.[1,2,3] In other words, obesity has reached epidemic proportions on a global scale.[4] Evidence indicates that obesity exerts deleterious effects on various facets of life, including both physical and psychosocial well-being.[5]

While extensive research has focused on the physical complications associated with obesity, less attention has been given to its connection with specific psychological pathologies, such as sexual function disorders. These conditions significantly diminish quality of life and have either been understudied or yielded contradictory results in the literature.[6,7,8] Researchers have documented evidence illustrating the detrimental impact of obesity on individuals’ sexual health.[9]

Numerous studies indicate that sexual performance is influenced by a multitude of factors.[10] Body mass index (BMI) is identified as one of the variables that can impact women’s sexual performance.[11] Studies exploring the association between BMI and sexual dysfunction in women have yielded contradictory results. While some investigations have identified a significant relationship between body mass index and sexual performance,[11,12,13] others have not reported such an association.[14,15] A meta-analysis revealed a 41% prevalence of female sexual dysfunction in 215,740 women of reproductive age.[16]

The relationship between sexual function and body weight has not been thoroughly investigated.[17] Studies conducted in Iran indicate that, on average, 86% of overweight and obese women experience sexual dysfunction.[11,18] The rates have been reported to be 91.8% and 3.3% among obese and overweight women, respectively.[18] The predominant disorder observed in these women is a decrease in sexual function and orgasmic dysfunction.[19]

Studies have demonstrated that increased sexual activity is associated with both physical and psychological benefits. These benefits include a reduction in cardiovascular events at older ages, a decreased risk of fatal coronary events, and potential protective effects against prostate and breast cancer.[20,21,22,23] Several mechanisms may explain the potential benefits of sexual activity on health and well-being. First, sexual activity can be considered a form of physical exercise.[24] Consequently, individuals engaging in regular sexual activity are likely to experience mental and physical health benefits.[25] Second, during sexual activity, particularly during orgasm, the release of endorphins, which are endogenous opioid peptides, acts as neurotransmitters, causing feelings of happiness or bliss.[26] Marital satisfaction is a crucial component of overall life satisfaction and has been a focal point of attention for social scientists globally.[27]

Due to social and cultural restrictions, the association between obesity and its potential impact on sexual function and marital satisfaction among Iranian women has not been thoroughly investigated. Considering its importance as an influencing factor on overall health, this study aimed to explore the relationships among body mass index, sexual function, and marital satisfaction among women attending health centers in Babol city, Iran.

Materials and Methods

Study design and setting

This study was a cross-sectional survey.

Study participants and sampling

The study was conducted on 350 married women who were selected via a cluster sampling as a two-stage selection method. The sample size was determined using G-power software, considering an effect size of 0.3,[28] a power of 80%, and a confidence level of 95%. The calculated sample size was 314 cases, with an additional provision for a 10% dropout, resulting in a final sample size of 350 individuals.

Data collection and technique

A two-stage sampling method was employed. Initially, urban healthcare centers were enumerated, and four centers were randomly selected using an online randomization module (www.random.org). In the second stage, the eligible individuals who met the inclusion criteria were sampled.

Inclusion criteria

To be eligible for participation, individuals were required to have a minimum level of education, including the ability to read and write. Other inclusion criteria included marital status, a stable sexual relationship with a spouse over the last 6 months, absence of polygamy, and an age range of 15–45 years.

Exclusion criteria

The exclusion criteria included menopause, pregnancy, breastfeeding, the presence of chronic conditions (including diabetes mellitus, multiple sclerosis, neoplasm, and cardiovascular disease), a history of surgeries such as hysterectomy and vaginal repair, symptoms of lower urinary tract infection, polycystic ovary syndrome, abnormal thyroid function, the use of medicines affecting sexual function, a history of surgery to treat obesity, a history of mental problems, and a body mass index less than 18.5 kg/m².

Following project approval and ethical clearance, a list of health centers was compiled from which four centers were randomly selected. The researcher visited these centers, introduced the study, and explained its objectives and methods to eligible women. Those interested in participating were asked to read and sign a written consent form before completing the research questionnaires. Participants were assured of the confidentiality and anonymity of their responses.

To calculate the body mass index (BMI), individuals’ weight was measured using a Falcon scale with a precision of 0.5 kg, and their height was measured with a tape measure on a wall with an accuracy of 0.1 cm. BMI was calculated by dividing weight (in kilograms) by the square of height (in meters). Participants were categorized into three groups based on BMI: normal (BMI ≥18.5 and <25), overweight (BMI ≥25 and <30), and obese (BMI ≥30). Measurements were conducted with attention to accuracy, and periodic checks were performed during the process.

Instruments

1. Demographic and Obstetric Characteristics Questionnaire:

   The demographic and obstetric characteristics questionnaire included information such as age (in years), education level, occupation, spouse’s education level, spouse’s occupation, sufficiency of family income, type of residence, length of time since marriage, date of last childbirth, method of childbirth, and number of children.

2. Women’s Sexual Function Inventory (FSFI):

   This questionnaire, which utilizes a Likert scale for scoring, comprises 19 questions across six domains: desire, arousal, lubrication, orgasm, satisfaction, and sexual pain.

   According to the instructions provided by the questionnaire designer, the scores for each domain were computed by summing the scores of the individual questions within the domain and multiplying the total by a specific factor. Given the uneven distribution of questions across domains in the FSFI questionnaire, equal weighting was applied by summing the scores first and then multiplying by the factor number. A score of zero indicates a lack of sexual activity within the past 4 weeks. The total scale score is derived by summing the scores across the six areas, with a higher score denoting better sexual function. Each domain has a maximum score of 6, resulting in a total scale maximum of 36. The minimum scores for sexual desire (1.2), sexual stimulation, vaginal lubrication, orgasm, pain (0), and satisfaction (0.8) contributed to a total minimum scale score of 2. The cutoff points for the entire scale and subscales are as follows: total scale,[28] desire (3.3), psychological stimulation (3.4), lubrication (3.4), orgasm (3.4), satisfaction (3.8), and sexual pain (8.3). Scores surpassing these cutoff points indicate good sexual function. Notably, the validity and reliability of the Persian version of the questionnaire were confirmed. Cronbach’s alpha was calculated to be 0.7 by Mohammadi et al.[29] in 2008.

3. Enrich Marital Satisfaction Questionnaire:

   This questionnaire was developed in 1989 and consists of 35 self-reported questions. Each item employs a 5-point Likert scale ranging from 1 to 5, with higher scores indicating greater marital satisfaction. The Cronbach’s alpha coefficient of the questionnaire, a measure of internal consistency, was reported as 0.92. The validity and reliability of the questionnaire were reported to be 95%.[30,31]

4. A portable electronic scale was used to measure weight with an accuracy of 0.1 kg.

5. A stadiometer, which is a precise instrument used for measuring height. A portable model of the Seca brand with an accuracy of 0.1 cm was used.

Ethical considerations

This research received ethical approval with the code IR.MUBABOL.REC.1400.069 from the Ethics Committee of Babol University of Medical Sciences. All project stages adhered strictly to the approved protocol. Participants were provided with detailed explanations regarding the project’s procedures and objectives, and written consent was obtained from each participant.

Statistical analysis

Data were analyzed using the SPSS software package (version 25, SPSS Inc.). Quantitative variables are described by mean and standard deviation, and qualitative variables are defined by number (percentage). The ANOVA test and Chi-squared tests were used to examine the relationship between variables. We used the Pearson correlation test to evaluate the correlation between sexual function and marital satisfaction. For statistical significance, two-sided P values less than 0.05 were considered statistically significant.

Results

The participants’ mean age was 31.92 ± 7.99 years, and their spouses’ mean age was 36.20 ± 7.8 years. The mean marriage duration was 20.54 ± 3.98 years.

In this study, the mean score for sexual performance was 21.67 ± 2.95, while the average score for marital satisfaction was 106.83 ± 5.20.

Table 1 shows the results of examining the relationships between sexual function, marital satisfaction, and demographic and obstetric characteristics.

Table 1.

Demographic characteristics of the participants included in the present study and their relationships with sexual function and marital satisfaction

Variable		Level		Frequency		Percentage		Sexual Performance				Marital satisfaction
								F		P		F		P
Age		≥25		96		27.4		36.65		<0.001		0.882		0.415
		26–35		137		39
		≥35		118		33.6
Education		Primary school		49		14		42.70		<0.001		3.90		0.021*
		High School and Diploma		151		43
		College/University		150		42.7
Spouse’s Education		Primary school		57		16.3		31.14		<0.001		3.81		0.023*
		High School and Diploma		132		34.7
		College/University		162		46.3
Residence		Urban		218		62.1		19.62		<0.001		2.093		0.149
		Rural		133		37.9
Spouse’s Occupation		Unemployed		20		5.2		7.53		0.006		0.045		0.83
		Employed		331		94.8
Occupation		Unemployed		232		66.3		15.82		<0.001		0.050		0.824
		Employed		118		33.6
Night Shift Job		Yes		33		27		9.57		0.002		1.15		0.276
		No		85		73
Remarriage		Yes		13		3.7		0.026		0.89		0.237		0.124
		No		338		96.3
Spouse’s Remarriage		Yes		21		5.5		0.227		0.634		3.14		0.077
		No		330		94.5
History of Pregnancy		Yes		253		72.3		26.94		<0.001		2.84		0.093
		No		98		27.7
History of Delivery		Yes		251		75.6		0.006		0.938		2.375		0.124
		No		100		24.6
Income Adequacy		Adequate		97		27.8		11.307		<0.001		1.07		0.344
		Partially adequate		241		69/1
		inadequate		13		3.7

Post hoc analysis revealed a noteworthy difference in sexual function among women with a normal body mass index and those categorized as overweight (P = 0.034) or obese (P < 0.001). Additionally, a significant difference was observed between the sexual function of individuals classified as overweight and those classified as obese [Table 2].

Table 2.

Relationships between sexual function dimensions and body mass index among women of reproductive age

Sexual Performance Dimensions		Body mass index						P *
		Normal (n=141)		Overweight (n=161)		Obese (n=49)
		Mean±SD		Mean±SD		Mean±SD		P (1*2)		P (1*3)		P (2*3)		P **
Sexual Sesire		4.1±0.79		30.96±0.74		3.69±1.07		0.326		0.010		0.114		0.013
Arousal		4.39±0.99		4.16±0.99		3.96±1.13		0.479		0.001		0.009		0.001
Lubrication		3.13±0.57		2.99±0.47		2.99±0.69		0.068		0.056		0.069		0.076
Orgasm		3.79±0.72		3.68±0.63		3.41±0.73		0.274		0.014		<0.001		0.006
Satisfaction		4.93±1.09		4.78±1.03		4.04±1.14		0.275		<0.001		<0.001		<0.001
Dyspareunia		2.05±1.14		2.79±0.86		2.05±1.06		0.234		0.99		0.527		0.060

*P-value post-hoc (LSD) test: Between the first and second groups, the first and third groups, and the second and third groups, **P-value ANOVA test: Between the first, second, and third groups

Table 3 shows a significant difference between the marital satisfaction dimensions of individuals in the overweight and obese categories.

Table 3.

Relationships between marital satisfaction dimensions and body mass index in women of reproductive age

Marital Satisfaction Dimensions		Body Mass Index						P *
		Normal (N=141)		Overweight (N=161)		Obese (N=49)		P (1*2)		P (1*3)		P (2*3)		P **
		Mean±SD		Mean±SD		Mean±SD
Marital Satisfaction		36.52±5.009		36.74±5.07		33.57±5.71		0.937		0.004		0.001		0.002*
Communication		36.75±5.84		36.28±6.46		33.18±5.04		0.783		0.002		0.007		0.002*
Conflict Resolution		35.28±4.78		34.92±5.08		32.71±4.44		0.803		0.007		0.021		0.009*
Idealistic Distortion		18.76±3.35		18.44±3.5		18.29±3.19		0.704		<0.001		0.001		<0.001*

*P-value post-hoc (LSD) test: Between the first and second groups, between the first and third groups, and between the second and third groups, **P value ANOVA test: Between the first, second, and third groups

Furthermore, a significant correlation was identified between sexual function and marital satisfaction among the participants. (r = 0.109, P = 0.041).

Discussion

The primary objective of this study was to explore the correlation between body mass index (BMI) and sexual function as well as marital satisfaction among women attending health centers. The findings revealed a significant difference in sexual function between women with a normal BMI, overweight women, and obese women. This finding aligns with previous research that has similarly established a significant connection between sexual function and BMI.[12,32,33] An Egyptian study revealed no difference between women (18–25 years old) with obesity and their normal weight counterparts regarding their overall sexual functioning score.[34] The researchers assumed that cultural values, education status, and beliefs might explain this finding. The findings of the present study are consistent with those of previous studies and show that an increased body mass index (BMI) is associated with a decrease in sexual function parameters.[28,35,36] Another study in 2012 revealed no significant association between BMI and women’s sexual function.[37] The controversies in the findings underscore the multifactorial nature of sexual health in women, with factors such as physiology, psychology, medications, infertility, lifestyle, and relationships all playing significant roles in the occurrence and progression of sexual disorders.[38]

Moreover, the study revealed a statistically significant relationship between BMI and several domains of sexual function, including libido, arousal, orgasm, and satisfaction. However, no significant relationship was observed in the domains of sexual lubrication and pain. While Mozafari et al.[11] identified a significant relationship between BMI and libido, arousal, and satisfaction, the same was not observed for sexual pain; Moreover, another report emphasized that women’s sexual desire is predominantly influenced by nonorganic factors such as self-confidence, previous sexual experiences, emotional connections, hormones, and mental health.[38] Our study suggested that obesity in women may contribute to sexual dissatisfaction by potentially causing relaxation of pelvic floor muscles due to increased pressure on pelvic contents.[39] The link between obesity and sexual dysfunction may operate through mechanisms such as increased medical problems, alterations in circulating hormone levels impacting sexual response, desire, and changes in body image.[40] These findings collectively emphasize the importance of considering a holistic range of factors when exploring the intricate relationship between BMI and sexual health in women.

The impact of obesity on sexual health extends beyond physiological factors, serving as a potential physical barrier to sexual intercourse. The inability to engage in sexual intercourse can contribute significantly to sexual dysfunction in women.[28] Another possible reason for the observed association is concerns about body image and lack of confidence among obese women.[41]

Interestingly, research on women who underwent weight loss surgery demonstrated that overall sexual function remained largely unchanged, yet specific dimensions such as libido and arousal significantly improved post-surgery compared to presurgery levels.[42]

Conversely, challenges in marital performance and strained marital relationships with a spouse can contribute to an individual feeling physically unattractive to their partner.[31] Consequently, while acknowledging the relevance of biological factors such as body mass index, it is crucial to recognize the impact of other variables on women’s satisfaction and sexual function. The current study’s findings indicate a significant reduction in marital satisfaction and its dimensions when comparing individuals with a higher body mass index. There was also a noteworthy correlation between sexual function and marital satisfaction among the participants. Identifying and addressing sexual disorders can have a substantial impact on enhancing the overall quality of marital relationships. Similarly, other studies have shown a significant relationship between sexual satisfaction and marital satisfaction.[43,44,45]

According to the results of the present study, which addresses the negative consequences of obesity on the sexual function and marital satisfaction of women, there is a pressing need for interventional studies to improve obese women’s knowledge and skills in sexual function, as well as reduce BMI, to achieve better sexual performance and consequently higher marital satisfaction.

Strengths and limitations of the study

A notable strength of this study is the deliberate exclusion of menopausal women, which minimized the influence of hormonal and psychological factors associated with menopausal age on sexual performance. This study has several limitations. Firstly, participants might underreport or overreport their sexual function and satisfaction due to social desirability or recall bias. the cultural and social context of Iran may influence both body image and relationship dynamics differently compared to other regions, potentially limiting the generalizability of the results to other populations. The cross-sectional nature of the current study makes it difficult to assess how changes in BMI over the years might affect sexual function and marital satisfaction.

Conclusion

This study revealed that obesity is related to sexual function and most of its domains. There is a relationship between BMI and marital satisfaction. Moreover, several socio-demographic factors are related to sexual function, such as the following:

Age, education, residency, occupation, night shift, history of pregnancy, and adequacy of income. However, marital satisfaction was related only to education. Cultural and biological influences might be important for interpreting women’s sexual behavior and marital satisfaction regarding their obesity.

Consent to participate

Informed consent was obtained from all subjects.

Consent for publication

Not applicable.

Ethics approval and consent to participate

The research protocol was approved by the Ethical Committee of Babol University of Medical Sciences (IR.MUBABOL.REC.1400.069). Consent letters were obtained from all the participants before the start of the study.

Availability of data and materials

Since our data contains sensitive personal information, sharing this data with a third party is forbidden without obtaining an additional written form of informed consent for information sharing. We did not get additional written consent for information sharing.

Competing interests

The authors declare that they have no competing interests.

Funding Statement

Nil.