Introduction

Multiple changes in normal lifestyle patterns such as eating habits, social behaviors, sleeping trajectories, and physical activities have been reported globally1,2,3,4. These changes are thought to be the consequences of the continuous alterations in the sociocultural, economic, technological, and psychological dynamics3,5. Weak family ties, financial difficulties, increased unemployment rates, the use of advanced technology (i.e., smart phones, artificial intelligence), and the occurrence of dramatic events triggering physiological and psychological distress (i.e., COVID-19 pandemic, conflicts) are among the leading risk factors that contributed to the development of numerous negative lifestyle patterns3,5,6,7. These negative lifestyle patterns, which include overeating, consuming unhealthy food, low quality sleep, and physical inactivity, resulted in the onset of many health issues such as chronic diet-related diseases, mental disorders, social impairments, and sleeping disorders1,4,6.

Globally, high rates of various sleeping disorders have been recorded8,9. These numbers were further amplified during the COVID-19 pandemic outbreak. Till this date sleeping disorders are regarded as one of the major aftermaths of the COVID-19 pandemic6,10. The most prevalent sleeping disorder cited was insomnia, which is mainly characterized as feeling dissatisfied with either the sleeping quality or quantity or both, subsequently resulting in clinical distress and substantial daytime function impairments8,9. Previous studies have shown that the prevalence and severity of insomnia were correlated with geographical region and ethnicity11,12,13,14. An annual survey conducted in Qatar (Social and Economic Survey Research Institute, Qatar University) found a positive association between Arab ethnicity and insomnia12. This association may be attributed to cultural factors such as daytime napping, late bedtime, and interrupted sleeping patterns that are more profound among Arab populations than non-Arab ones. This finding was echoed in a cross-sectional study by Titi et al.13 who reported a high prevalence of insomnia (72.1%) among Arab participants from 12 Arab countries. The authors further showed that clinically significant insomnia prevalence was in accordance with participants’ country, and that among the upper middle-income countries investigated, Jordan exhibited the highest prevalence of insomnia compared to its counterparts, Palestine and Lebanon13. Sex, age, the presence of mental and/or medical diseases, socioeconomic status, and duration of sleep were among the significant predictors associated with insomnia onset11,14,15,16. Generally, insomnia was associated with being female, young (20–35 years), having low socioeconomic status, suffering from mental disorders (i.e., depression) and/or medical diseases (i.e., obesity), and sleeping shorter durations14,15,16,17,18. Nevertheless, when it comes to sex, studies have shown inconsistent results, in which some studies demonstrated that women were more prone to insomnia than men12,18, while other studies showed either a strong association between insomnia and being a male or insignificant differences between both sexes14,19,20. Paine et al.20 highlighted that the influence of sex on insomnia risk may be moderated by multiple factors including cultural or societal factors, hence, insomnia’s prevalence should be investigated among both sexes, including men.

It is well-established that persistent insomnia can diminish a person’s quality of life and result in detrimental physiological and psychological issues21,22,23. Therefore, a wide spectrum of sleeping therapies and interventions have been proposed and tested to manage this sleeping disorder21,22,24. From sleep or insomnia-specific targeted interventions to generic psychological or pharmacological approaches, these therapies did, to a certain degree, delay insomnia’s onset and/or alleviate its symptoms21,22,25. Among proposed treatments, dietary interventions have been increasingly investigated for their potential role in the prevention/treatment of insomnia. Specific food items and dietary patterns were shown to delay or prevent the onset of insomnia22,26,27.

Mediterranean diet (MD) is known to be an intangible cultural-geographical heritage pattern originated in civilizations that resided in the areas surrounding the Mediterranean Sea28,29. The sui generis nature of this diet is attributed to the distinct dietary pattern that focuses on the high consumption of plant-derived foods (i.e., fruits, nuts, legumes), concurrent with moderate to low intakes of animal-derived foods and sugary items (i.e., dairy products, meat, sweets). These food items either individually or synergistically with other MD components exhibit favorable effects on cardiovascular diseases, diabetes, obesity, inflammatory diseases, mental disorders, among other disorders28,30. Recent studies have also highlighted the important role of MD on sleeping patterns27,29,31. For example, epidemiological studies have demonstrated that poor quality diets characterized by low consumption of plant-derived foods and high consumption of animal-derived, processed foods and sugar-containing foods were significantly associated with sleeping disorders, including insomnia24,26. MD, on the other hand, was reported to improve both the quality and quantity of sleep24,26,32,33. Moreover, previous studies have reported an inverse association between insomnia severity and adherence to the MD among Iranian adolescent girls31, Arabic-speaking women in Jordan27, and university students (males and females) in Spain33. This significant association between the MD and insomnia has been attributed to the vital food components present (i.e., vegetables, fruits, olive oil) in the MD24,26,32.

Given the high prevalence of insomnia globally and its correlation to the region, ethnicity, and sex, and the limited studies conducted on Arab men, as well as the possible effects of adherence to MD on this sleeping disorder, the current study aims to investigate the prevalence of insomnia and the potential predictors of insomnia among Arab-speaking men living in Jordan, including MD adherence. The findings of this study can help delineate the factors associated with insomnia among Arab-speaking men living in Jordan, particularly adherence to the MD and facilitate the development of interventions (diet and physical activity) that can help treat or alleviate insomnia for this targeted population group.

Materials and methods

Design

A cross-sectional, correlational design was conducted. Arab-speaking men living in Jordan were invited to participate in this study.

Sample and setting

A convenience sample of 536 Arabic-speaking men from 10 Arab nationalities (Jordan, Syria, Palestine, Kingdom of Saudi Arabia, Egypt, Yamen, Lebanon, Morocco, Iraq, and Qatar) living in Jordan were included in this study. After removal of incorrect entries and outliers (n = 7), the data from 529 participants were included in the final analyses. The data collection was conducted on August 1st, 2022, over a period of one month. The study’s inclusion criteria were: (1) being a male; (2) aged 18 and older; (3) currently living in Jordan and (4) able to read, write, and speak the Arabic language. Participants who did not meet the inclusion criteria were excluded from the study.

Participants were asked to complete an adapted version of the previously validated questionnaire measuring MD adherence, level of physical activity, and insomnia 34,35,36,37,38. The survey was translated into simple, straightforward, Arabic language. Online Google forms were used to construct the adapted online survey, which was then distributed through advertisements on social media and other online platforms and hubs (i.e., WhatsApp, Facebook, Instagram, Microsoft Teams). In addition, participants were encouraged to share the survey link with other potential participants who matched the inclusion criteria. The study data was saved on a secure Google Drive that was only accessible to the principal investigator and data analyst. Coded data were provided to the rest of the research team.

Assuming a Confidence Interval level of 95% (CI) with an alpha level of 5%, and an estimated type 2 error of around 20% of the surveyed values of the male population of 244,750,991 in the Middle East and North Africa, the estimated sample size was around 38539. Thus, the study sample size exceeded the sample size needed (N = 536). The guidelines of the Method for Observational Studies in Nutritional Epidemiology (STROBE-nut) were employed to enhance the quality of the study design and reporting40.

Ethical approval

This study was approved by the Institutional Review Boards (IRB) of the University of Petra (reference no. E/1H/1/2021), Amman, Jordan. This study was conducted in accordance with the Declaration of Helsinki. Before beginning the survey, participants were provided with information regarding the study and were asked if they were still willing to participate in the study. Only those who agreed to participate in the study were able to complete the survey. Thus, completion of the survey constituted participants’ informed consent for inclusion in this study. Participants who were interested in participating in the study were directed to a google form, in which they were asked if they were male, aged 18 and older, currently living in Jordan and are able to read, write, and speak the Arabic language. Participants were assured that their participation in the study was voluntary, anonymous, and that they could withdraw from the study at any time.

Study’s instruments

Participants were asked to complete an Arabic version of the four measures: (1) sociodemographic investigator-developed questionnaire; (2) Adherence to MD Questionnaire; (3) The General Practice Physical Activity Questionnaire (GPPAQ); and (4) Athens Insomnia Scale (AIS).

Three doctorly prepared experts who are proficient in both Arabic and English languages participated in the (1) translation, (2) backtranslation, and reviewing the forward translation and backtranslation of the measures into the Arabic language, as well as verifying the conceptual and cultural equivalence. The final version of the culturally adapted translated measures were reviewed until consensus was achieved.

A sociodemographic investigator-developed questionnaire

The questionnaire consisted of sociodemographic information (i.e., educational level, marital status, smoking status, anthropometric measurements (weight and height)). Body mass index (BMI) was calculated from the weight and height data collected using the following formula (BMI = weight (kg)/ [height (m)]2). Lastly, the hydration/dehydration status was measured as the frequency of water intake (1 glass = 330 ml)41. Thus, an individual is categorized as hydrated if he/she reported drinking at least 8 glasses (~ 2.6 L) of water per day, otherwise, he/she is categorized as dehydrated41.

Adherence to Mediterranean Diet (MD) questionnaire

The study utilized an adapted version of the MD score tool that comprised of fourteen dichotomous (Yes/ No) questions. Both Trichopoulou et al.37 and PREDIMED (Prevención con Dieta Mediterránea)42 methodologies were adapted to examine the participants’ adherence to the MD. The adapted version consisted of the following food items: Olive oil, legumes, vegetables, fruits, nuts, meat and poultry, fish, carbonated drinks, sweets/ pastries, and alcohol. The total MD score ranged from < 6 (low MD adherence), 6–9 (moderate MD adherence), to ≥ 10 (high MD adherence). A score of 0 was assigned when the consumption of presumed beneficial components (olive oil, vegetables, fruits, legumes, fish, nuts, food dishes seasoned with sofrito (sauce of vegetables simmered with olive oil)) was lower than the median consumption, otherwise a score of 1 was assigned. For presumed harmful components (meat products, butter/ cream, carbonated drinks, commercial sweets/ pastries), a score of 1 was assigned when consumption was lower than the median consumption, otherwise a score of 0 was assigned. Likewise, a score of 1 was assigned when participants used olive oil as the main culinary fat and preferentially consume white meat instead of red meat, otherwise a score of 0 was assigned. For alcohol use, a score of 1 was assigned when consumption of ethanol for men was 10–49 g/day, otherwise a score of 0 was assigned. The test-retest reliability of this tool was reported to be very good42. In this study, the Arabic version of the MD questionnaire had a moderate reliability with a Cronbach’s Alpha of 0.545.

The general practice physical activity questionnaire (GPPAQ)

The GPPAQ is a short self-report questionnaire used to assess the physical activity levels among adults (16–74 years), which was developed by the London School of Hygiene and Tropical Medicine (LSHTM)36. The questionnaire consisted of 3 parts that are based on physical activity and occupation. In the first part, participants were asked about the type and amount of physical activity performed within their work (1 item), while in the second part, participants were asked to report the number of hours they spent on specific physical activities (5 items). In the last part, participants were asked to describe their walking pace. Based on the scoring algorithm provided for the GPPAQ by LSHTM, participants were classified into four categories: active, moderately active, moderately inactive, or inactive36.

Athens insomnia scale (AIS)

The study evaluated insomnia among men living in Jordan during the previous month using the Athens Insomnia Scale (AIS), which was developed by Soldatos et al.38. The AIS is a self-assessment, four-point Likert scale instrument that consists of  8 items. The first 5 items focus on sleep quality and quantity, which include: sleep induction, night-time awakening, final awakening, total sleep duration, and sleep quality. The remaining 3 items focus on the individual’s well-being, functioning capacity, and daytime sleepiness. The total score ranged from 0 “no sleep-related problems” to 28 “severe insomnia”. A cutline of 5.5 is used to identify individuals with insomnia, in which participants’ scores are categorized as either having insomnia if they scored 5.5 or above or as not having insomnia if they scored below 5.538. In the current study, the Arabic version of the AIS had good reliability with a Cronbach’s Alpha of 0.773.

Statistical analysis

Data were analyzed using IBM® Statistical Package for the Social Sciences (SPSS®) Statistics Version 26 (IBM Corp., Armonk, NY) and Python Scikit-learn library version 0.16.1 (Scikit-learn library, Machine Learning in Python, 2010). Descriptive statistics including the means and standard deviations (continuous variables) and frequencies and percentages (category variables) summarizing the study’s data were reported based on the variable’s level of measurement.

To identify potential predictors of insomnia among Arab men living in Jordan, a multivariate logistic regression was performed. The model included both sociodemographic (educational level, marital status, occupation, smoker status) and health-related variables (BMI, hydration/dehydration status, physical activity, adherence to the MD, number of meals per day, and number of sleep hours per day). The outcome variable was the insomnia score. The significance level was set at p< 0.05.

Results

Participants’ demographic characteristics

Table 1 represents the sociodemographic characteristics of the study’s participants. A total sample of 529 participants were included in the final analyses. Most of the participants were Jordanian (n = 406, 76.7%), had a college degree (n = 413, 78.1%), were not married (n = 395, 74.7%), and were categorized as dehydrated (n = 458, 86.6%). Around half of the participants were currently working (n = 258, 48.8%) and smokers (n = 302, 57.1%). The mean weight and height of the participants were 80.4 ± 15.9 kg and 180.6 ± 74.1 cm, respectively. Based on the calculated BMI, 45.5% of participants (n = 241) had a normal weight. The physical activity measured by the GPPAQ showed that 55.2% of the participants (n = 292) were categorized as moderately inactive to inactive. As for the frequency of meals consumed per day, 52.9% had at least 3 meals per day. For more information, please see Table 1.

Table 1 Sample Characteristics of Arabic-Speaking Men Participants Living in Jordan (N = 529).
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Mediterranean diet adherence score (MD adherence score)

The MD adherence scores of the 529 Arabic-speaking men living in Jordan are shown in Table 2. Around half of the participants had a moderate MD adherence score (MD score 6–9). While 21.7% of the participants had a low MD adherence score (MD score < 6) and 26.7% of participants reported a high MD adherence score (MD score ≥ 10). For more information, please see Table 2.

Table 2 Mediterranean Diet Adherence Scores of Arabic-Speaking Men Participants Living in Jordan (N = 529).
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Sleeping quality assessment

The assessment of the sleeping quality of the participants via sleeping duration (hours/night) and the AIS are presented in Table 3. Around 41.0% of the participants (n = 216) reported sleeping less than 6 hours per night. Based on AIS, more than half of the study’s participants suffered from insomnia (n = 285, 53.9%). For more information, please see Table 3.

The percentage of participants who reported very delayed sleep induction or did not sleep at all was 9.6% (n = 51). Around 17% (n = 88) of participants had considerable awakening problems during the night or had serious awakening problems during the night/did not sleep at all. Regarding the quality of sleep and the total sleep duration, only 3.0% of participants reported unsatisfactory quality of sleep or did not sleep at all (n = 16), while 2.8% of participants (n = 15) had insufficient duration of sleep or did not sleep at all. As for the well-being, normal activities, and feeling asleep during the day, around 5.0% of the study’s participants reported decreased well-being (n = 25), while 3.6% of participants had decreased physical and mental functioning (n = 19), and 5.5% of participants reported intensified feelings of sleepiness during the day (n = 29). Moreover, 3.6% of the participants (n = 19) stated awakening much earlier than desired or not sleeping at all.

Table 3 Sleeping Quality Assessment of Arabic-Speaking Men Participants Living in Jordan (N = 529).
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Predictors of insomnia

In the unadjusted bivariate logistic regression model, the findings revealed that those who were unemployed or retried (categorized as “not working”) had 90% greater relative risk of suffering from insomnia compared to those who were currently working (OR = 1.90, p = 0.018). In addition, those who were overweight (BMI between 25.0 and 29.9) had 30% greater relative risk of suffering from insomnia compared to men who had normal weight (BMI between 18.5 and 24.9) (OR = 1.30, p = 0.035). Moreover, men who drank less than 8 cups of water a day (categorized as dehydrated) had 20% greater relative risk of having insomnia compared to those who drank at least 8 cups of water a day (categorized as hydrated) (OR = 1.20, p = 0.020). Those who reported high adherence to the MD (score ≥ 10) were also at 60% greater relative risk of experiencing insomnia compared to those with moderate adherence to the MD (score 6–9) (OR = 1.60, p = 0.010). Lastly, those who had less than 6 hours of sleep per day, had 110% greater relative risk of experiencing insomnia compared to those who slept at least 6 hours (OR = 2.10, p < 0.001).

In the adjusted multivariate logistic regression model, which includes all the variables, the Nagelkerke R2 value for this model was 0.125. The study findings indicated that those who were married had a 40% reduction in the relative risk of experiencing insomnia (OR = 0.601, p = 0.034) compared to those who were not married (either single, divorced, or widowed). Meanwhile, those who reported high adherence to the MD had a 64% greater relative risk of suffering from insomnia (OR = 1.642, p = 0.028) compared to those who reported moderate adherence to the MD. Finally, men who reported less than 6 hours of sleep per day had 176% greater relative risk of experiencing insomnia (OR = 2.760, p < 0.001) compared to those who slept at least 6 hours per day. For more information, please see Table 4.

Table 4 Predictors of Insomnia Among Arabic-Speaking Men Participants Living in Jordan (N = 529).
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Discussion

Sleeping trajectories is one of the lifestyle patterns that have been continuously changing throughout time and were adversely affected amid the COVID-19 pandemic outbreak3,6,7. This is evident by the high prevalence of numerous sleeping disorders worldwide, including insomnia8,9. Insomnia has been significantly associated with increased morbidity and mortality rates, as well as economic burden (i.e., low productivity)14,23,43. Thus, this study examined the associated factors and possible predictors of insomnia, including the relationship between insomnia and specific diet patterns, namely adherence to Mediterranean diet (MD) among Arab men living in Jordan.

The study revealed that 53.9% of the participants suffered from insomnia. This finding is in line with previous studies, which showed a high prevalence of insomnia among Arab men12,14,44. Moreover, in the unadjusted model, the study demonstrated that there was a positive significant association between unemployment and insomnia (p = 0.018). Previous studies have documented the significant association between insomnia, income level and employment status8,12,15. Accordingly, individuals with low income were more likely to suffer from sleep problems and insomnia compared to those with high income. Given that employment is the strongest determinant of income, unemployment is therefore associated indirectly with insomnia. In addition, employment is perceived as a life event that is related to economic independence, success, maturity and muscularity, fatherhood, and its connection to cultural and social respect15,43. Hence, Arab men who are unemployed may be more prone to stress, low self-esteem, anxiety, and depression, all of which may have triggered adverse physical and psychological disorders, including the onset of insomnia9,14.

The study also demonstrated that there was a positive significant association between overweight (BMI between 25.0 and 29.9 kg/m2) and insomnia (p = 0.035). The relationship between insomnia and BMI has been previously investigated and the findings reported remain inconsistent18,45,46. Both Guandalini et al.17 and Tan et al.47 identified overweight and obesity (BMI ≥ 25.0 kg/m2) as strong predictors of insomnia, which is in part consistent with the findings of this study. On the other hand, Awadalla and Al-Musa48 found that being underweight (BMI < 18.5 kg/m2) was a strong predictor of insomnia. Meanwhile, a meta-analysis by Chan et al.45 demonstrated that there was no significant association between BMI and insomnia. It is important to note that in the current study, the association between insomnia and obesity (BMI ≥ 30.0) was not significant (p = 0.623). This nonsignificant correlation may be attributed to the small sample size of participants who were obese (n = 67). In addition, alteration in the amount of body weight alone may have not contributed to changes in the subjective sleep parameters tested in this study, but rather it may be the result of the combination of other factors such as marital status and sleep duration. Moreover, despite BMI being the standard parameter widely used for weight categorization, it alone may not represent an accurate measurement for assessing body fat, especially for men46. Hence, the association between insomnia and BMI in this study should be interpreted with caution, and further studies using additional body fat estimation tools and longitudinal studies are warranted to examine this association.

The current study also indicated that there is a significant association between insomnia and drinking less than 8 cups of water per day (categorized as dehydrated, p = 0.020). The relationship between insomnia and hydration status has recently been the focus of many studies24,49,50. A recent cross-sectional study reported that increased water intake (hydration) coupled with decrease in tea and coffee intake were significantly associated with better sleep parameters24. On the other hand, other studies have shown an insignificant association between sleep parameters and dehydration49,50. Thus, the mechanism(s) connecting dehydration with insomnia appears to be complex and ambiguous. However, some studies have suggested that dehydration can lead to symptoms such as thirst, fatigue, headaches, restlessness, and stress, all of which can cause impairment in sleep parameters and the onset of numerous sleep disorders such as insomnia49,50. Moreover, dehydration has been reported to adversely affect the circadian rhythm, a key regulator of the sleep-wake cycle, consequently leading to sleep difficulties and possibly insomnia49,50. Thus, these mechanisms may explain the significant association between insomnia and dehydration found in this study.

In the adjusted multivariate logistic regression model, married Arab men were significantly less likely (p = 0.034) to suffer from insomnia compared to men who were not married (single, divorced, or widowed). This finding aligns with previous studies which reported a higher insomnia prevalence among single, divorced, and widowed men compared to married men14,23,51. This can be explained by the possible protective role of marriage in providing men with the necessary social and emotional support. Moreover, existing literature conducted during the COVID-19 pandemic and afterward revealed that individuals who were married reported lower prevalence of psychological stress disorders compared to non-married ones51,52. Given the strong association between psychological distress disorders and insomnia9,15,17, it makes sense that married men who experience less psychological symptoms, are less likely to suffer from insomnia.

In the current study, both unadjusted and adjusted models demonstrated that adherence to the MD and sleep duration were both significant predictors of insomnia. Literature indicated that diet plays a vital role in the prevention and treatment of non-communicable diseases, including insomnia24,26. Furthermore, certain food groups (i.e., vegetables and fruits) and individual nutrients (i.e., vitamin D, monosaturated fats) were clinically reported to improve numerous sleep parameters and reduce insomnia symptoms24. Recently, investigations have shifted from examining individual food items toward studying the cluster of food items, as well as specific dietary patterns and their correlation with sleep parameters26,32. In general, studies have reported an inverse relationship between adherence to the MD and insomnia, thus, participants with higher adherence to the MD reported a lower incidence of insomnia, and vice versa27,53. On the contrary, the results of the current study revealed that high adherence to the MD was significantly associated with higher prevalence of insomnia among Arab men (unadjusted p = 0.010; adjusted p = 0.028). One possible explanation for this finding is that although MD has beneficial effects against insomnia, some of the food items within it (i.e., dairy products, alcohol) have been shown to have an inverted U-like relationship with insomnia. For example, a study conducted by Hepsomali and Groeger24 reported that participants who had either low or high intakes of dairy products scored lowest in sleep quality. In addition, a study by Ayre et al.54 indicated that alcohol consumption has been reported to either reduce or aggravate insomnia symptoms depending on both amount of intake (i.e., quantity) and time of consumption. Moreover, red meat and other animal sources of high-quality proteins have been shown to have a dual effect on an individual’s quality of sleep. This could be explained by the high saturated fat (increase insomnia) and high protein (amino acid tryptophan which improves sleep) contents26,32. Hence, the dual and complex effects of some of the food items within the MD may have contributed to the current study findings. Furthermore, the consumption of unsweetened caffeinated beverages such tea and coffee were not accounted for when calculating the MD adherence score37. High consumption of caffeinated beverages causes alertness and awakening, which in turn may result in sleep difficulties and insomnia26,55. It is well-known that in Arab countries, tea and coffee are essential beverages consumed daily and during social events as a part of the Arabic hospitality55. Therefore, not accounting for the possible consumption of large amounts of these caffeinated beverages, especially among Arab men, may explain the high prevalence of insomnia among this target population despite their high adherence to the MD. Another possible explanation for the high prevalence of insomnia despite MD adherence score is the interaction between other factors such as sex and BMI. Godos et al.53 reported that the beneficial effect of MD adherence on sleep parameters was only significant in participants who had normal weight or were overweight, but not among participants who were obese. According to the authors, the effect of MD adherence on sleep parameters was indirect and mediated by metabolic effects as evident in participants who were either normal weight or overweight53. Moreover, a recent study by Mohammadi et al.56 reported that participants with normal weight had lower odds for having poor sleep quality, however this association was not significant among overweight/ obese participants. The authors postulated that overweight/ obese participants might have other unhealthy lifestyle habits that were not accounted for in the study, which may have diminished the MD beneficial effect on sleep quality56. Scoditti et al.29 also reported that adherence to the MD was inversely associated with insomnia only in women, but not in men. This was thought to be due to predisposing factors such as hormones and other behavioral factors (i.e., more adherence to healthy diet) that are more common in women, making women more prone to insomnia compared to men and hence, more affected by dietary interventions/patterns such as MD29. Lastly, it is important to note that most MD adherence studies were cross-sectional studies that utilized self-report questionnaires thus, it was not possible to develop a causal association between MD adherence and insomnia.

Finally, the current study indicated that Arab men who slept less than 6 hours were more likely to suffer from insomnia (p < 0.001). This finding is supported by previous studies, which indicated that short sleep duration (< 6 hours) was associated with insomnia16,19. As a matter of fact, studies have also shown that insomnia along with shorter sleep duration are considered a severe phenotype insomnia associated with detrimental health effects such as hypertension and diabetes16,19.

Limitations and future implications

The current study has several limitations: First, the study utilized a cross-sectional design, thus, it was difficult to infer a causal relationship between insomnia and the factors examined in the study. Hence, randomized controlled design studies are needed to investigate the causal relationship between insomnia and these factors. Second, the study used self-report questionnaires and thus, responses may be influenced by socially desirable responses and recall bias. Therefore, the use of objective measurements, as well as other measures to control for socially desirable responses may be warranted. Third, the study did not include any information regarding participants’ age or intake of unsweetened caffeinated beverages (i.e., tea and coffee), length of residence of Arabic non-Jordanian men in Jordan, which may have limited the study’s ability to generalize its findings to this population. Thus, age, unsweetened caffeinated beverages, and length of residence of Arabic non-Jordanian men in Jordan should be included in future studies examining predictors of insomnia. In addition, the variables in the study explained 12.5% of the variability in insomnia occurrence. Thus, other variables should be examined. Finally, the tools used in the study to determine predictors of insomnia such as BMI and hydration status are general and may have not accurately assessed these factors. In addition, the adapted MD scale reported moderate reliability of 0.545. Hence, the findings of this study should be interpreted with caution. Although the translated measures demonstrated acceptable reliability, future studies should conduct in-depth psychometric properties evaluation of these translated measures.

Conclusions

In conclusion, the current study demonstrated that there is a high prevalence of insomnia among Arab men living in Jordan. Being unemployed, categorized as dehydrated (drinking less than 8 cups of water per day), and being overweight increased the participant’s risk for insomnia. On the other hand, being married and sleeping for at least 6 hours a day were considered protective factors against insomnia. Despite the high adherence to the MD reported among the study’s participants, both adjusted and unadjusted models revealed that participants with high adherence were at higher risk of developing insomnia. This may be attributed to other confounding factors such as sex, BMI, and the dual effect of MD’s individual food items on insomnia. Given the high prevalence of insomnia detected among Arab men in this study and the unexpected effect MD adherence had on insomnia, further studies are needed to investigate the effects of MD’s individual food items, age, and the use of unsweetened caffeinated beverages on insomnia. The findings of the study provide valuable insight regarding the prevalence of insomnia and factors that may have contributed to it. This information can help form the foundation of future intervention studies to target insomnia among Arab men.