Associations of health literacy with rational drug use awareness and sleep hygiene in older adults: a cross-sectional study

Abstract

Objective

This study was conducted to evaluate the relationship between health literacy, awareness of rational drug use, and sleep hygiene among home-dwelling older adults in Istanbul.

Methods

This cross-sectional survey was conducted between May 2024 and August 2024 among 174 older adults living in Istanbul. Participants completed a Personal Information Form, the Health Literacy Scale, the Rational Drug Use Awareness Scale, and the Sleep Hygiene Index. Exclusion criteria included psychiatric diseases, cognitive problems, refusal to participate, and receiving institutional care. Data were analyzed using IBM SPSS Statistics version 28. Descriptive statistics (means, standard deviations, frequencies, and percentages) were calculated as appropriate. Group comparisons were performed using one-way ANOVA or Kruskal–Wallis tests depending on distributional assumptions, with appropriate post hoc analyses (Tukey HSD or Mann–Whitney U tests). Correlations between continuous variables were assessed using Spearman’s rho. Multiple linear regression analyses were conducted to examine variables associated with health literacy, rational drug use awareness, and sleep hygiene. In addition, an exploratory mediation analysis was performed using a regression-based approach with bootstrap resampling (5,000 samples) to assess the indirect association of rational drug use awareness in the relationship between health literacy and sleep hygiene. Statistical significance was set at p < 0.05.

Results

Education level and income perception were significant predictors of health literacy (p < 0.001 and p = 0.007, respectively). Rational drug use awareness was significantly associated with sleep hygiene (p < 0.001) and income perception (p < 0.01). In multiple linear regression analysis, rational drug use awareness emerged as the only significant predictor of sleep hygiene (R² = 0.189, p < 0.001). No significant associations were observed for gender, marital status, or having children (all p > 0.05).

Conclusion

Health literacy was shaped by education level and income perception, whereas rational drug use awareness was associated with sleep hygiene. These findings suggest that targeted health education and medication awareness initiatives may be particularly relevant for older adults from lower socioeconomic backgrounds.

Introduction

Population aging has brought increasing attention to how older adults manage their health, including their use of medications and strategies to maintain sleep quality. Globally, more than 50% of medications are inappropriately prescribed, distributed, or sold, and nearly half of patients fail to take them correctly, while a substantial portion of the world’s population still lacks access to essential medicines [1]. Additionally, in geriatric patients sleep disorders are among the most frequent health problems that may lead to medication misuse. Epidemiological studies indicate that the prevalence of insomnia symptoms in older populations ranges broadly; for example, Yang et al. report values between 3% and 62. % [2], and Zhong et al. found approximately 3% prevalence of clinical insomnia in older Chinese primary care patients [3]. Additionally, Guo et al. observed poor sleep quality in 53.0% of their studied older sample [4]. Simultaneously, the prevalence of polypharmacy (≥ 5 medications) in older population worldwide is estimated at 391% (5% CI 35.5–427%), with hyperpolypharmacy (≥ 10 medications) around 133% [5]. These data underscore the intersection of high rates of sleep disturbances and extensive medication use in older populations, forming a critical backdrop for exploring the link between sleep disorders and irrational pharmacotherapy in geriatrics [6]. This intersection highlights that sleep-related problems in later life cannot be considered independently from medication use and management practices.

Prevalence data from Türkiye similarly indicate high rates of sleep complaints in later life [7]. A recent community-based study reported poor sleep quality in approximately 55% of older adults [8], while national reports also highlight widespread sleep disturbances among older individuals [9]. In this scope inappropriate medication use is not only a pharmacological problem but also strongly shaped by health literacy, which determines how effectively geriatrics patients understand and apply medical instructions.

The level of awareness about health has great importance for the older adults before, during and after receiving health services in terms of understanding the instructions of health workers and being able to apply the healthy ways for use of medicines [10]. The rapidly growing geriatric patient group worldwide makes it crucial to study this phenomenon in old age group [11]. The health literacy of geriatric patients is related to long-term care dependency and frailty [12]. In Türkiye, large-scale national data similarly show that 71.9% of older population have problematic or inadequate health literacy, with education level identified as the primary determinant of HL performance [13, 14]. Some systematic reviews have shown that self-assessments of health literacy in older people are associated with medication adherence [15–17]. However, the role of health literacy in shaping awareness of rational drug use and sleep-related medication practices remains insufficiently explored. This highlights the need for studies with more inclusive samples that represent diverse regions and populations when evaluating health literacy among older population [18]. Despite growing literature on health literacy, few studies have simultaneously addressed its association with rational drug use awareness and sleep hygiene in elderly populations [19]. This gap is particularly evident in the Turkish context, where no previous studies have examined these interrelated factors together [20]. As geriatric patients are the most common consumer group in healthcare, it is important to ensure that they have a high level of health literacy, interact with quality health information and are protected from iatrogenic risks [21]. One of the most important iatrogenic risks is the violation of the principles of rational drug use [22]. Thus, strict adherence to rational drug use is critical for optimizing patient health outcomes and minimizing treatment costs [23]. Health literacy plays a critical role in sleep-related medication use by influencing individuals’ ability to understand indications, risks, and side effects of commonly prescribed hypnotics and sedatives. Older adults with limited health literacy may be more likely to rely on pharmacological solutions for sleep complaints, have difficulties interpreting non-pharmacological recommendations, or misuse sleep-related medications in terms of dosage and duration. In contrast, higher health literacy may support more cautious medication use and greater engagement in sleep hygiene practices, thereby reducing the risk of inappropriate pharmacotherapy.

Rational drug use (RDU) is a rule that must be followed for patients to take drugs according to their needs, the right dosage, sufficient time intervals, and the least cost to themselves and society [24]. Türkiye has implemented a National Rational Drug Use Action Plan led by the Ministry of Health, emphasizing physician–pharmacist collaboration, patient education, and public campaigns to reduce inappropriate medication use [25, 26]. Prescribing drugs to the older people based on risk and balancing the risk-benefit ratio is very important. This age group are more susceptible to adverse drug reactions (ADRs) due to age-related changes in the metabolic system and a decrease in drug clearance, further exacerbating the increase in drug usage [27]. Rational drug use provides many benefits such as life options, goal-oriented treatment, effectiveness of intervention and appropriate use of cost [28]. For this aim rational drug use implementations have critical importance for older patients. Among the various factors contributing to improper medication use, sleep disorders are one of the most common issues affecting older people [29].

Rather than focusing on normative sleep recommendations, this section emphasizes the prevalence, clinical consequences, and medication-related implications of sleep disorders in later life. The most common sleep disorders seen in the geriatric patients are sleep latency, decreased sleep efficiency, and total sleep time. Common sleep problems include chronic insomnia, circadian rhythm sleep-wake disorders, sleep-related movement disorders, and sleep-related breathing disorders [30]. Sleep disorders represent one of the leading conditions that complicate medication use in older patients. Neurobiological evidence indicates that sleep disturbances are linked with neurotransmitter alterations, neuroinflammation, and cognitive decline, all of which increase vulnerability to inappropriate or excessive pharmacological treatment [31]. In geriatric practice, sleep complaints are often associated with polypharmacy, since hypnotics and sedative medications are frequently prescribed without sufficient evaluation of underlying causes, despite the limited validation of sleep assessment tools in this population [32]. This reciprocal relationship creates a cycle where untreated or misdiagnosed sleep problems prompt medication use, while drug side effects further impair sleep quality [33]. Therefore, integrating systematic sleep assessments into geriatric care is essential to support rational pharmacological and non-pharmacological strategies, and to minimize iatrogenic risks [34]. Insomnia and other sleep disorders in older adults are not only associated with impaired quality of life but also have significant clinical consequences [35]. Evidence shows that insomnia increases the risk of developing depression, with older individuals suffering from persistent sleep problems being more vulnerable to affective symptoms [36]. Furthermore, chronic insomnia has been linked to accelerated cognitive decline, suggesting a potential pathway to dementia in cognitively normal older people [37].

Sleep disturbances also raise the risk of falls, which represents a major source of morbidity and mortality in geriatrics [38]. In addition, insomnia contributes to poorer control of chronic conditions such as hypertension and diabetes, thereby increasing overall morbidity and healthcare utilization [39]. The pharmacological treatment of insomnia itself carries risks, as sedative-hypnotics can cause sedation, cognitive impairment, and an increased incidence of falls [40]. Collectively, these findings highlight the multifaceted clinical burden of insomnia in older patients, reinforcing the importance of its careful assessment and rational management.

Providing sleep hygiene and supporting non-pharmacological treatments are often recommended for geriatric patients. Since the quality of evidence for pharmacological treatment is low, drug selection should be based on shared decision-making between the practitioner and the patient and should have limited prescription [41]. However, there are few studies measuring the use of sleeping pills in the older and their health literacy and awareness of rational drug use [42]. Rational drug use in sleep disorders is related to the selection of appropriate active substance, dose and duration [29]. For example, medications such as benzodiazepines and antidepressants should be avoided for the treatment of insomnia in older patients [43]. Behavioral and habit-based interventions aimed at sleep hygiene are very effective in the management of sleep disorders [18]. One possible explanation for the observed association is that individuals with higher rational drug use awareness may avoid medications that negatively impact sleep patterns, such as sedatives and stimulants, and may be more cautious about potential side effects that disrupt sleep. Despite growing evidence linking health literacy to medication use and a substantial body of literature addressing sleep problems in later life, these domains have largely been examined separately. In particular, the relationship between health literacy, rational drug use awareness, and sleep hygiene has rarely been investigated in an integrated manner among community-dwelling older adults. Moreover, evidence from middle-income countries and non-Western contexts remains limited, restricting the generalizability of existing findings. In this study examines the associations between health literacy, rational drug use awareness, and sleep hygiene among community-dwelling older people, addressing a gap in the Turkish context where these interrelated factors have not previously been evaluated together.

Method

This research employs a quantitative, cross-sectional survey approach, which includes both phone calls and online data collection methods. A non-probability convenience sampling strategy with consecutive enrollment was used. Eligible participants were recruited consecutively during the data collection period based on accessibility and willingness to participate. Recruitment was conducted via community channels and social contacts in Istanbul. Data were collected using both telephone interviews and an online survey platform. Participants were not randomly assigned to data collection modes; instead, the method was determined based on participants’ access to digital tools and personal preference. Telephone interviews were conducted with participants who had limited internet access or preferred verbal communication, whereas the online questionnaire was administered to participants who were able and willing to complete the survey electronically. To minimize potential mode bias, the same standardized questionnaire, item wording, and response options were used across both data collection methods. Interviewers followed a structured script during telephone interviews to ensure consistency with the online format. The primary objective is to assess the health literacy, rational drug use awareness, and sleep hygiene practices of older population living in Istanbul. The inclusion criteria for participation in the study are: to be aged ≥ 60 years and to be community-dwelling residents of Istanbul, willingness to participate, and no psychiatric or cognitive disorders. Psychiatric and cognitive conditions were assessed by self-report of a prior clinician diagnosis and/or ongoing treatment. Participants who reported a diagnosis of dementia or moderate to severe cognitive disorder, or an active psychiatric disorder under treatment, were excluded. No formal neurocognitive screening test was administered as part of this survey. In addition, prior to data collection, participants were required to successfully respond to brief orientation and communication questions administered by the researcher to confirm adequate comprehension and orientation.

Data is collected with three scales and demographic form. All instruments were used in their Turkish-validated versions (HLS-EU: Okyay et al.; RDU Awareness Scale: Aktaş & Selvi; SHI: Özdemir et al.). The Health Literacy Scale (HLS-EU), developed within the framework of the European Health Literacy Study, was adapted and validated in Turkish by Okyay et al., and consists of 32 items rated on a 5-point Likert scale (1 = very easy, 5 = very difficult). The internal consistency (Cronbach’s alpha) of the full scale is 0.95, with sub-scale alpha values ranging from 0.81 to 0.94 [44]. Rational Drug Use Awareness Scale is developed by Aktaş and Selvi (2019), consists of 15 items rated on a 5-point Likert scale. Some items are reverse scored. The scale measures the participant’s awareness regarding the appropriate use of medications. The total score range is 15–75, and the Cronbach’s alpha for the scale is reported as 0.83 [45]. Sleep Hygiene Index (SHI) is developed by Mastin et al. (2006) and validated in Turkish by Özdemir et al. (2015), this scale consists of 13 items. It uses a 5-point Likert scale to assess the frequency of healthy sleep behaviors. The score range is 13–65, with higher scores indicating worse sleep hygiene [46].

Since there is no study measuring these parameters simultaneously in the Turkish population, the sample size was maximized by taking the effect size as small as possible. An a priori power analysis was conducted using G*Power (version 3.1) for multiple linear regression (fixed model, R² deviation from zero) with eight predictors, an alpha level of 0.05, and a desired power of 0.80. Assuming a small-to-moderate effect size (Cohen’s f² ≈ 0.10–0.15) in accordance with conventional standards for multiple linear regression, the required sample size was estimated to range between approximately 160 and 180 participants. To account for potential non-response and attrition, an additional 10% was added, resulting in a target sample size of 198 participants. Of these, a total of 174 participants were included in the final analysis after excluding individuals who did not meet the eligibility criteria or had incomplete responses. The final sample size therefore remained adequate to meet the a priori power requirements of the study.

Statistics

Statistical analyses were conducted to examine the relationships among health literacy, rational drug use (RDU) awareness, sleep hygiene, and demographic variables. Descriptive statistics (mean, standard deviation, frequency, percentage) were used to summarize sample characteristics. Group differences were evaluated using one-way ANOVA or Kruskal–Wallis tests based on distributional assumptions, with Tukey HSD and Mann–Whitney U tests applied for post hoc pairwise comparisons where appropriate. Because several variables did not meet normality criteria (Shapiro–Wilk p < 0.05), Spearman’s rho correlation coefficients were calculated to assess bivariate associations among health literacy, RDU awareness, sleep hygiene, and age. A single directional analytic framework was specified in which sleep hygiene was treated as the primary outcome variable and RDU awareness as an explanatory behavioral variable, with health literacy modeled as an upstream predictor. Accordingly, two hierarchical multiple regression models were estimated: RDU awareness regressed on health literacy and sociodemographic covariates (age, gender, education, income, marital status), and sleep hygiene regressed on RDU awareness and the same covariates. Multicollinearity was assessed using the variance inflation factor (VIF), with all values below 5, indicating no multicollinearity concerns. To examine whether RDU awareness accounted for the association between health literacy and sleep hygiene, an exploratory mediation analysis was performed. The a-path (RDU awareness ~ health literacy) and the b-path (sleep hygiene ~ RDU awareness) were estimated, and the indirect effect (a×b) was evaluated with 5,000 bootstrap samples. A 95% bootstrap confidence interval not crossing zero was interpreted as evidence of a statistically meaningful indirect association. Because the data are cross-sectional, mediation findings are interpreted as associations rather than causal pathways. All analyses were performed using IBM SPSS Statistics version 28, and statistical significance was set at p < 0.05.

Ethics approval and consent to participate

The study was approved by the Istanbul Gelisim University Ethics Committee (Approval Date: 10.05.2024, Approval Number: 2024-06), and conducted in accordance with the principles of the Declaration of Helsinki. Prior to participation, informed consent was obtained from all participants: verbal consent was documented for telephone interviews, and electronic written consent was recorded for online respondents. Participation was voluntary and anonymous, and participants could withdraw at any time without consequence.

Results

A total of 174 participants were included in the study. Descriptive statistics sociodemographic characteristics and main study variables are presented in Table 1. Participants had a mean age of 69.9 years (SD = 5.45; range: 60–94). Overall, the sample was predominantly female and characterized by low levels of health literacy, whereas more than half of the participants demonstrated high awareness of rational drug use. The majority of participants reported good or moderate sleep hygiene. Internal consistency coefficients indicated acceptable reliability for all scales used in the study.

Table 1.

Rational drug use awareness, health literacy and sleep hygiene levels

Category	Level	n	Percent
Rational Drug Use Awareness Level (SD = 0.65)	Low awareness	16	9.2%
	Medium awareness	62	35.6%
	High awareness	96	55.2%
Health Literacy Level (SD = 0.89)	Insufficient health literacy	127	73.0%
	Problematic-limited health literacy	33	19.0%
	Excellent health literacy	14	8.0%
Sleep Hygiene Level (SD = 0.67)	Good sleep hygiene	106	60.9%
	Moderate sleep hygiene	58	33.3%
	Poor sleep hygiene	6	3.4%
	Very poor sleep hygiene	4	2.3%
Total		174	100%

The internal consistency of the measurement instruments was acceptable, with Cronbach’s alpha values of 0.77 for the Rational Drug Use Awareness Scale, 0.82 for the Sleep Hygiene Index, and 0.80 for the Health Literacy Scale. Item–total correlation coefficients exceeded 0.30 for all items

As age, rational drug use awareness, and sleep hygiene scores were not normally distributed (p < 0.05), bivariate associations were examined using Spearman’s rank correlation analysis. A significant negative correlation was observed between rational drug use awareness and sleep hygiene (r = − 0.31, p < 0.01), indicating that higher awareness was associated with better sleep hygiene, as lower scores on the Sleep Hygiene Index reflect more favorable sleep practices. No significant correlations were found between health literacy and either rational drug use awareness or sleep hygiene (both p > 0.05). Age was positively correlated with rational drug use awareness (r = 0.19, p < 0.05), suggesting that awareness increased with advancing age. Correlation coefficients are presented in Table 2.

Table 2.

Spearman’s rho correlation analysis results between age, sleep hygiene index, rational drug use awareness and health literacy levels

	Sleep Hygiene	Rational Drug Use Awareness	Health Literacy	Age
Sleep Hygiene	1.000	− 0.310**	0.118	− 0.088
Rational Drug Use Awareness	− 0.310**	1.000	− 0.140	.187*
Health Literacy	0.118	− 0.140	1.000	0.135
Age	− 0.088	0.187*	0.135	1.000

N = 174, significant correlations at * p < 0.05, ** p < 0.01

ANOVA revealed a significant difference in health literacy scores across income perception groups (F(2, 171) = 5.31, p = 0.006). Post hoc Tukey HSD analysis indicated that participants with a good income perception had significantly higher health literacy scores compared with those reporting poor or moderate income perception, whereas no significant difference was observed between the poor and moderate income groups (Table 3).

Table 3.

Tukey HSD multiple comparison results for health literacy scores by income perception

Group 1	Group 2	Mean Difference	Std Error	p-value	Confidence Interval (95%)
Poor	Medium	2.14194	2.41140	0.640	-3.55– 7.84
Poor	Good	6.29412	2.48829	0.033*	0.41– 12.17
Medium	Good	4.15217	1.48004	0.015*	0.65–7.65

* p < 0.05, ** p < 0.01 indicates statistical significance

Kruskal–Wallis analyses revealed significant differences across income perception groups for both rational drug use awareness (H = 16.84, p < 0.001) and sleep hygiene (H = 15.26, p < 0.001). Participants reporting a good income perception demonstrated higher awareness of rational drug use and better sleep hygiene (lower Sleep Hygiene Index scores) compared with other groups. Post hoc Mann–Whitney U tests indicated significant differences primarily between the moderate and good income groups, whereas no differences were observed between the poor and moderate groups (Table 4). With respect to education level, significant group differences were observed for age (p = 0.009), health literacy (p < 0.001), and rational drug use awareness (p = 0.001), but not for sleep hygiene (p = 0.152). Post hoc analyses showed that participants with lower educational attainment had significantly lower rational drug use awareness compared with those with higher education levels. Detailed pairwise comparisons are presented in Table 4.

Table 4.

Post hoc Mann-Whitney U test results for pairwise comparisons across educational levels

Comparison	Variable	Mann-Whitney U	Z	p-value
Literate - Elementary	Rational Drug Use Awareness	75.500	-3.696	0.000**
Literate - High School	Rational Drug Use Awareness	88.500	-2.439	0.015*
Literate - University	Rational Drug Use Awareness	132.000	-3.152	0.002**
Literate - Postgraduate	Rational Drug Use Awareness	27.500	-3.590	0.000**
Elementary - University	Age	1038.000	-2.491	0.013*
Elementary - High School	Rational Drug Use Awareness	537.000	-2.280	0.023*
High School - Postgraduate	Sleep Hygiene	239.500	-1.986	0.047*
University - Postgraduate	Sleep Hygiene	497.000	-1.709	0.087

* p < 0.05, ** p < 0.01 indicates statistical significance

Multiple linear regression analysis indicated that education level (β = −0.495, p < 0.001) and perception of average monthly income (β = −0.193, p = 0.007) were significantly associated with health literacy. The overall model was statistically significant (R² = 0.319, F(8, 163) = 9.56, p < 0.001), explaining 31.9% of the variance in health literacy scores. Other variables, including gender, marital status, having children, sleep hygiene, rational drug use awareness, and sleep medication use, were not significant predictors (all p > 0.05). No multicollinearity was detected (VIF < 5), and residuals demonstrated acceptable normality. Regression coefficients are presented in Table 5.

Table 5.

Regression coefficients for predictors of health literacy

Variable	B	Std. Error	Beta	t-value	p-value	VIF
Constant	33.981	9.034	-	3.761	0.000**	-
Income Perception	-2.894	1.050	-0.193	-2.755	0.007**	1.174
Gender	-0.228	1.292	-0.012	-0.177	0.860	1.078
Marital Status	2.468	1.482	0.115	1.665	0.098	1.141
Having Children	-1.367	2.833	-0.033	-0.483	0.630	1.087
Education Level	-2.942	0.391	-0.495	-7.528	0.000**	1.034
Sleep Medication Use	1.758	3.122	0.037	0.563	0.574	1.039
Sleep Hygiene Index	0.028	0.079	0.026	0.359	0.720	1.231
Rational Drug Use Awareness	-0.029	0.076	-0.028	-0.382	0.703	1.289

* p < 0.05, ** p < 0.01 indicates statistical significance

Sleep hygiene was defined as the primary outcome variable in the regression analyses. According to the multiple linear regression analysis, rational drug use awareness (β = −0.331, p < 0.001) was the only significant predictor of the Sleep Hygiene Index. The model was statistically significant (R² = 0.189, F(8, 163) = 4.736, p < 0.001) and explained 18.9% of the variance in sleep hygiene scores. Other variables (health literacy, gender, marital status, parental status, education level, sleep medication use, and income perception) were not significant (all p > 0.05). Multicollinearity was not detected (VIF < 5), and residuals demonstrated acceptable normality. Although health literacy was not a significant predictor of sleep hygiene in the multiple regression model, an exploratory mediation analysis was conducted to examine potential indirect pathways via rational drug use awareness. While rational drug use awareness was significantly associated with sleep hygiene, the indirect effect of health literacy on sleep hygiene through rational drug use awareness did not reach statistical significance, as the bootstrap confidence interval included zero. Accordingly, neither the direct (c′) nor the total (c) effect of health literacy on sleep hygiene was significant. Regression coefficients for predictors of sleep hygiene are presented in Table 6.

Table 6.

Regression coefficients for predictors of sleep hygiene

Variable	B	Std. Error	Beta	t-value	p-value	VIF
Constant	44.290	8.628	-	5.134	0.000**	-
Income Perception	-1.688	1.053	-0.124	-1.603	0.111	1.209
Gender	-0.056	1.276	-0.003	-0.044	0.965	1.078
Marital Status	2.052	1.467	0.106	1.399	0.164	1.147
Having Children	-0.140	2.799	-0.004	-0.050	0.960	1.088
Education Level	0.613	0.445	0.114	1.376	0.171	1.378
Sleep Medication Use	-0.540	3.085	-0.013	-0.175	0.861	1.041
Rational Drug Use Awareness	-0.309	0.071	-0.331	-4.365	0.000**	1.155
Health Literacy	0.028	0.077	0.031	0.359	0.720	1.468

* p < 0.05, ** p < 0.01 indicates statistical significance

Exploratory mediation analysis indicated that rational drug use awareness was significantly associated with sleep hygiene (b = − 0.324, p < 0.001), whereas health literacy was not significantly associated with rational drug use awareness (a = − 0.067, p = 0.425) nor directly with sleep hygiene (c′ = 0.068, p = 0.377). The indirect effect of health literacy on sleep hygiene through rational drug use awareness was not statistically significant (a×b = 0.022; 95% bootstrap CI: −0.038 to 0.088). As the confidence interval included zero, mediation was not supported (Table 7).

Table 7.

Exploratory mediation analysis of health literacy, rational drug use awareness, and sleep hygiene

Pathway	B	SE	p-value
Health literacy → Rational drug use awareness (a)	−0.067	0.085	0.425
Rational drug use awareness → Sleep hygiene (b)	−0.324	0.072	< 0.001
Health literacy → Sleep hygiene (direct, c′)	0.068	0.077	0.377
Indirect effect (a×b)	0.022	—	95% CI − 0.038 to 0.088

*Bootstrap confidence intervals were estimated using 5,000 resamples and adjusted for age, gender, education level, income perception, and sleep medication use

Figure 1 presents the exploratory mediation model examined in the study, with health literacy specified as the independent variable, rational drug use awareness as the potential mediator, and sleep hygiene as the outcome variable. Solid arrows indicate statistically significant paths, whereas dashed arrows represent non-significant associations. The a-path denotes the association between health literacy and rational drug use awareness, the b-path represents the association between rational drug use awareness and sleep hygiene, and the c′ path reflects the direct association between health literacy and sleep hygiene after adjustment. All analyses were adjusted for age, gender, education level, income perception, and sleep medication use. Given the cross-sectional design, the model reflects statistical associations rather than causal relationships.

Fig. 1.

Conceptual mediation model examining the association between health literacy, rational drug use awareness, and sleep hygiene

Discussion

The present study examined the associations between health literacy, rational drug use awareness, and sleep hygiene among community-dwelling older adults. The key finding is that rational drug use awareness emerged as the primary factor associated with sleep hygiene, whereas health literacy was not directly associated with sleep hygiene in this sample. These findings highlight the importance of medication-related awareness in shaping sleep-related behaviors in later life. Education level and perceived income emerged as the strongest correlates of HL, while RDU awareness was the principal correlate of sleep hygiene; the exploratory mediation analysis did not support a statistically significant indirect HL→RDU→sleep hygiene pathway. Our HL findings agree with prior evidence showing that higher educational attainment is linked to better navigation of health services and understanding of medical information [47]; similar patterns were reported by Geboers et al. (2018) for appraisal and navigation skills.

The observed association between rational drug use awareness and sleep hygiene may be explained by more cautious medication behaviors among individuals with higher awareness. Older adults who are more aware of rational drug use principles may be less likely to misuse sedatives or other medications that adversely affect sleep, and may be more attentive to medication timing, dosage, and potential side effects. These observations are consistent with the view that educational interventions can strengthen HL among older adults Turkish data also indicate substantial HL challenges in late life—problematic or inadequate HL in a large majority of elders—with education as a key determinant [48]. It also means Turkish older adults skill on navigating health services and medical decision-making often require complex information-processing skills [13]. Complementary results from Türkiye show positive associations between HL and quality of life in older populations [49] Internationally, age-related declines and shifting correlates of HL have been documented [50] and inadequate HL has even been identified as a stronger predictor of poor outcomes than income level, underscoring the tight link between socioeconomic position and HL [51].

The linkage between RDU awareness and sleep hygiene is less developed in the literature, yet our results are in line with reports on the harms of inappropriate pharmacotherapy in older adults. Benzodiazepines and related sedatives carry heightened risks in late life—including cognitive impairment and falls—which can disrupt sleep architecture and daytime function [52]. Recent clinical observations also describe irrational medication use among patients with insomnia, reinforcing the interplay between medication practices and sleep behavior [53]. Within this context, higher RDU awareness may support safer medication decisions and greater reliance on non-pharmacological strategies, aligning with our finding that better RDU awareness accompanies healthier sleep practices. In Türkiye, the widespread family physician model, the advisory role of community pharmacists, national rational drug use campaigns, and strong public health messaging in television and visual media have contributed to broader awareness of safe medication practices [25, 26]. These system-level mechanisms may help sustain relatively high RDU awareness even among individuals with lower HL. Interestingly, although health literacy was not directly associated with sleep hygiene in either bivariate or multivariable analyses, exploratory mediation analysis suggested an indirect relationship operating through rational drug use awareness. This finding indicates that health literacy may contribute to sleep-related behaviors by enhancing patients’ understanding and awareness of appropriate medication use, rather than exerting a direct influence on sleep hygiene itself. Such an indirect pathway is plausible in geriatric populations, where medication-related knowledge and behaviors play a critical role in daily health management.

Although an exploratory mediation analysis was conducted to examine potential indirect pathways, the indirect effect of health literacy on sleep hygiene through rational drug use awareness was not supported. This finding should be interpreted cautiously, as all analyses were based on cross-sectional data and reflect statistical associations rather than causal relationships. The absence of simple bivariate correlations but the presence of significant adjusted regression coefficients suggests that other demographic and contextual variables may moderate the relationship [54]. The absence of a statistically significant mediation effect is consistent with previous evidence indicating that health literacy–behavior relationships in older adults are often context-dependent and shaped by system-level supports rather than operating through a single linear mediating pathway [47, 55, 56].

We observed no significant associations between the primary outcomes and gender, marital status, or parental status. Prior studies have likewise reported minimal gender differences in HL once education is accounted for [24]. In our sample, socioeconomic gradients (education and perceived income) may have absorbed most between-group variability, leaving little residual contribution from these demographic indicators.

From a practice perspective, these results support targeted, low-cost approaches: (i) integrating medication-literacy/RDU awareness modules into routine primary care, pharmacy counseling, and nurse-led visits; (ii) pairing medication review with brief sleep hygiene education; and (iii) prioritizing groups with lower education or limited resources. Such multidisciplinary efforts could reduce inappropriate sedative use and improve sleep-related well-being in older adults.

The educational profile of the sample may have played an important role in shaping the observed findings. Although a substantial proportion of participants had completed higher levels of formal education, the overall level of health literacy remained low, supporting previous evidence that educational attainment does not necessarily translate into adequate functional health literacy [57]. This discrepancy may partially explain why health literacy did not emerge as a significant direct predictor of sleep hygiene or rational drug use awareness in the regression analyses. Prior studies have shown that low health literacy can attenuate observed associations with health behaviors, particularly in older populations and in domains requiring complex self-management skills [58, 59]. Moreover, behaviors such as medication use and sleep-related practices rely not only on basic education but also on interactive and critical health literacy skills, which may be insufficiently captured by formal education alone [60, 61].

An additional noteworthy observation in this study was the coexistence of low overall health literacy with relatively high awareness of rational drug use. Although formal educational attainment is often associated with general literacy, research indicates that higher levels of formal education do not always translate into adequate functional health literacy in older adults, particularly as cognitive processing demands increase with age and in complex health decision contexts [15, 57]. Furthermore, domain-specific awareness such as rational medication use may be shaped by repeated clinical encounters, targeted health communication, or system-level influences rather than by general health literacy alone [55, 56]. Prior evidence also suggests that low health literacy may attenuate or mask direct associations with certain health behaviors when examined in standard regression models, especially in complex self-management domains such as medication adherence and sleep behavior [62]. Together, these perspectives highlight that a distinction between general health literacy and specific medication-related awareness is important when interpreting the behavioral outcomes observed in geriatric populations.

Taken together, the regression findings indicate that different dimensions of health-related behavior in later life may operate through partially independent mechanisms. While education level and perceived income were strongly associated with health literacy, rational drug use awareness emerged as the principal factor associated with sleep hygiene. The lack of a direct association between health literacy and sleep hygiene, as well as the absence of a statistically significant indirect effect via rational drug use awareness, suggests that health literacy does not uniformly translate into specific health behaviors among older adults. Previous research has shown that health literacy–behavior relationships in later life are often context-dependent and shaped by system-level supports, repeated clinical encounters, and domain-specific knowledge rather than by general health literacy alone [55, 56]. In this context, medication-related awareness may represent a more proximal behavioral construct influencing sleep-related practices, whereas broader health literacy skills may play a more distal role in daily health management [43, 59].

Limitations

This study has several limitations. Because the design was cross-sectional, causal relationships cannot be inferred, and the directionality of the associations remains uncertain. Additionally, all variables were measured through self-report instruments, which may introduce recall bias and social desirability effects. The study sample consisted of older adults residing in Istanbul, and many participants had relatively higher levels of education compared to the general older population, which limits the generalizability of the findings to other regions and demographic groups. Future research employing longitudinal or experimental designs, and including more diverse samples, would help clarify the temporal and causal nature of these associations and improve external validity.

Conclusion

In conclusion, rational drug use awareness was associated with better sleep hygiene among community-dwelling older adults, whereas health literacy was not directly related to sleep hygiene in this cross-sectional study. These findings indicate that higher levels of health literacy and rational medication practices may be associated with better sleep-related behaviors and indicators of well-being in later life. Considering the high prevalence of sleep difficulties and the potential risks of inappropriate medication use in older adults, incorporating basic sleep hygiene guidance into routine pharmacological counseling may represent a practical and low-cost approach. Future research should explore whether programs designed to enhance rational drug use awareness are associated with reduced reliance on sleep medications among older adults.

Authors’ contributions

NE and FSA jointly designed the research. NE drafted the Introduction, Discussion, and Conclusion sections, while FSA handled the Methodology and Data Analysis. NE also managed the overall formatting and final revisions. Both authors reviewed and approved the final manuscript.

Funding

This study was supported by the Coordination Unit of Scientific Research Projects of İnönü University under grant number SBA-2025-4109, covering Article Processing Charges (APC) and open access fees.

Data availability

The datasets generated and analyzed during the current study are available in anonymized form from the corresponding author upon reasonable request.

Declarations

Competing interests

The authors declare no competing interests.