Association between Siesta (Daytime Sleep), Dietary Patterns and the Presence of Metabolic Syndrome in Elderly Living in Mediterranean Area (Medis Study): The Moderating Effect of Gender

Daytime napping and cardiovascular risk factors, cardiovascular disease, and mortality: A systematic review

Associations between night sleep duration and cardiovascular risk factors in adults have been well documented. However, the associations for daytime napping remain unclear. In this review, six databases were searched for eligible publications to April 8, 2022. A total of 11 articles were identified for umbrella review on the association of daytime napping with diabetes, metabolic syndrome (MetS), cardiovascular disease (CVD), and mortality in adults, 97 for systematic review on the association with CVD and several CVD risk factors. Our umbrella review showed that the associations of daytime napping with diabetes, MetS, CVD, and mortality in most meta-analyses were mainly supported by weak or suggestive evidence. Our systematic review showed that long daytime napping (≥1 h/d) was associated with higher odds of several CVD risk factors, CVD, and mortality, but no significant association was found between short daytime napping and most of the abovementioned outcomes. Our dose-response meta-analyses showed that daytime napping <30 min/d was not significantly associated with higher odds of most CVD risk factors and CVD among young and middle-aged adults. However, among older adults aged >60 years, we observed significant dose-response associations of daytime napping with higher odds of diabetes, dyslipidemia, MetS, and mortality starting from 0 min/d.

Association of elevated glycated hemoglobin and obesity with afternoon napping for more than 1 h in young and middle-aged healthy adults

INTRODUCTION

Sleep has different patterns followed worldwide and can be influenced by social, cultural, and environmental factors. Daytime napping is commonly practiced in different parts of the world with controversial results of its effect on glucose metabolism. The current study aims to examine the association of afternoon napping and night sleep duration with metabolic derangements.

METHODS

This is a cross-sectional study involving young adults and middle-aged subjects. Anthropometric measurements were taken for height and weight and hip and waist ratio. Consented subjects were asked to wear actigraphy for 1 week and run their usual daily activities. Home sleep apnea testing was performed to exclude obstructive sleep apnea. Subjects had been asked to come fasting on day seven for blood collection to test for fasting glucose, glycated hemoglobin, lipid profile, and insulin.

RESULTS

A total of 405 subjects were involved to complete the study (52% male, 48% female). The mean age of participants was 32.8 ± 11.5 years. The study indicated that the duration of afternoon napping was significantly associated with abnormal glycated hemoglobin (HbA1c > 5.7%) (p = 0.01) and body mass index (p = 0.046) independent of age, gender, and nocturnal sleep duration. Nocturnal sleep duration was associated with increased insulin level (p = 0.04).

CONCLUSION

Afternoon napping is associated with an increased level of glycated hemoglobin and obesity and that may predispose to the development of type 2 diabetes mellitus.

Midday Napping and Successful Aging in Older People Living in the Mediterranean Region: The Epidemiological Mediterranean Islands Study (MEDIS)

The aim of the present study was to investigate the association between midday napping, sleeping hours, and successful aging among 2564 older (65+ years) individuals living in the insular Mediterranean region. Anthropometric, clinical, and socio-demographic characteristics, dietary habits, and lifestyle parameters were derived through standard procedures, while successful aging was evaluated using the validated Successful Aging Index (SAI; range 0-10). Of the 2564 participants, 74% reported midday napping. The SAI score was 2.9/10 for non-midday nappers vs. 3.5/10 for midday nappers (p = 0.001). Midday nappers were more likely to be physically active (p = 0.01) and to have higher adherence to the Mediterranean diet (p = 0.02) compared to non-midday nappers. In a fully adjusted model, midday nappers had 6.7% higher SAI score compared to the rest (p < 0.001), and the effect of midday napping was more prominent among males and participants 80+ years of age. Further analysis indicated a significant U-shaped trend between sleeping hours/day and SAI score (p < 0.001), with 8-9 h total of sleep/day, midday napping included, proposed as optimal in achieving the best SAI score. Midday napping seems to be a beneficial habit that should be promoted and encouraged in older people.

Associations between sleep and obesity indices in older adults: results from the HELIAD study

BACKGROUND

Short sleep duration and low sleep quality are negatively associated with obesity in young adults, but in older people the results are inconsistent.

AIMS

The aim of the present study was to examine the associations between sleep duration and quality with both body mass index (BMI) and waist circumference (WC) and to investigate sex- and age-specific associations in a population-representative cohort of older adults.

METHODS

1781 participants ≥ 65 years old from the HELIAD study were included. Sleep duration and quality were based on self-report, whereas BMΙ and WC were evaluated clinically.

RESULTS

Sleep duration was inversely related to WC, only in women, even after adjustment for age, sex, years of education, total energy intake and level of physical activity. Furthermore, sleep quality was negatively related to both BMI and WC in women. In men, however, no significant relationships were observed between these variables. Associations between sleep and weight did not differ between those aged < 73 and ≥ 73 years old.

DISCUSSION

To the best of our knowledge, this is the first study examining both sleep duration and quality with BMI and WC in older adults, performing by-sex analysis. Although additional studies are needed, improvements in sleep habits should be considered in weight management of older individuals.

CONCLUSIONS

Our results suggest that poor sleep is associated to adverse weight effects in older women, but not men.

Sleep, Diet, and Cardiometabolic Health Investigations: a Systematic Review of Analytic Strategies

PURPOSE OF REVIEW

Poor sleep is a risk factor for cardiometabolic morbidity. The relationship of sleep and cardiometabolic health could be confounded, mediated, or modified by diet, yet the incorporation of diet in sleep-cardiometabolic health studies is inconsistent. This rapid systematic literature review evaluates the conceptualization of diet as a confounder, mediator, or effect modifier within sleep-cardiometabolic health investigations, and the statistical approaches utilized.

RECENT FINDINGS

Of 4692 studies identified, 60 were retained (28 adult, 32 pediatric). Most studies included diet patterns, quality, or energy intake as confounders, while a few examined these dietary variables as mediators or effect modifiers. There was some evidence, mostly in pediatric studies, that inclusion of diet altered sleep-cardiometabolic health associations. Diet plays a diverse role within sleep-cardiometabolic health associations. Investigators should carefully consider the conceptualization of diet variables in these relationships and utilize contemporary statistical approaches when applicable.

Gender-specific, Lifestyle-related Factors and 10-year Cardiovascular Disease Risk; the ATTICA and GREECS Cohort Studies

Background:

Lifestyle remains a huge driving force of Cardiovascular Diseases (CVD) onset/ progression. Lifestyle-patterns are highly dependent on gender-related attitudes.

Objective:

To evaluate the gender-specific association of lifestyle-related factors (adherence to Mediterranean diet (MedDiet), Physical Activity (PA), smoking) with 10-year first and recurrent CVD events.

Methods:

Two prospective studies, the ATTICA (2002-2012, n=3,042 subjects free-of-CVD) and GREECS (2004-2014, n=2,172 subjects with Acute Coronary Syndrome (ACS)) were undertaken. Baseline adherence to MedDiet (MedDietScore <27/≥27, range 0-55), PA (sedentary/physically active) and smoking (current/never) was tested against 10-year first (ATTICA) and recurrent (GREECS) CVD events, in men and women.

Results:

The “superiority” of men over women regarding overall CVD events was revealed in both first (ATTICA, 19.7% men vs. 11.7% women, p<0.001) and recurrent CVD events, but less significantly (GREECS, 38.8% men vs. 32.9% women, p=0.016). Gender-stratified analysis revealed that: lower adherence to MedDiet in women (Odds Ratio (OR)=1.22, 95% Confidence Interval (95%CI) 1.03, 1.51) and PA (OR=1.35, 95%CI 1.01, 1.85) and smoking (OR=1.28, 95%CI 1.04, 1.82) in men, were independent predictors of 10-year first CVD event; whereas, adherence to MedDiet (OR=1.28, 95%CI 1.01, 1.59), PA (OR=1.25, 95%CI 1.01, 2.50) and smoking (OR=1.15, 95%CI 1.01, 1.30) in women, yet only adherence to MedDiet (OR=1.27, 95%CI 1.01, 1.35) and PA (OR=1.27, 95%CI 1.02, 1.59) in men, were independent predictors of 10-year CVD recurrent events.

Conclusion:

Differences between men and women, in the effect-size measures of lifestyle-related factors, underline different paths for men and women, probably contributing to better designing strategies for primary and secondary CVD prevention.