A prospective study on the association of sleep duration with grip strength among middle-aged and older Chinese

Lower motor performance is linked with poor sleep quality, depressive symptoms, and grey matter volume alterations

Motor performance (MP) is essential for functional independence and well-being, particularly in later life. However, the relationship between behavioural aspects such as sleep quality and depressive symptoms, which contribute to MP, and the underlying structural brain substrates of their interplay remains unclear. This study used three population-based cohorts of younger and older adults (n=1,950) from the Human Connectome Project-Young Adult (HCP-YA), HCP-Aging (HCP-A), and enhanced Nathan Kline Institute-Rockland sample (eNKI-RS). Several canonical correlation analyses were computed within a machine learning framework to assess the associations between each of the three domains (sleep quality, depressive symptoms, grey matter volume (GMV)) and MP. The HCP-YA analyses showed progressively stronger associations between MP and each domain: depressive symptoms (unexpectedly positive, r=0.13, SD=0.06), sleep quality (r=0.17, SD=0.05), and GMV (r=0.19, SD=0.06). Combining sleep and depressive symptoms significantly improved the canonical correlations (r=0.25, SD=0.05), while the addition of GMV exhibited no further increase (r=0.23, SD=0.06). In young adults, better sleep quality, mild depressive symptoms, and GMV of several brain regions were associated with better MP. This was conceptually replicated in young adults from the eNKI-RS cohort. In HCP-Aging, better sleep quality, fewer depressive symptoms, and increased GMV were associated with MP. Robust multivariate associations were observed between sleep quality, depressive symptoms and GMV with MP, as well as age-related variations in these factors. Future studies should further explore these associations and consider interventions targeting sleep and mental health to test the potential effects on MP across the lifespan.

Accelerometer-assessed sleep and decline in physical function in older men

OBJECTIVES

Assess the prospective association of actigraphically measured sleep with self-report and objective measures of physical function among community-dwelling older men.

METHODS

Participants were (n = 1496) men aged ≥65 years from the Osteoporotic Fractures in Men Study and ancillary sleep study who were followed up at 4 years for physical function outcomes. Sleep predictors included baseline total sleep time (<6, 6-8 hours [reference], >8 hours), sleep efficiency (<80% or ≥80% [reference]), wake after sleep onset (<90 [reference] or ≥90 minutes), and sleep onset latency (<30 [reference] or ≥30 minutes), measured by wrist actigraphy. Outcomes included self-reported difficulties in mobility and instrumental activities of daily living and objective measures of physical performance (time to complete chair stands, gait speed, grip strength, best narrow walk pace). Multivariable regression models estimated associations between the sleep predictors and change in physical function at follow-up, adjusting for demographic and health-related variables.

RESULTS

Participants with short average baseline total sleep time (<6 hours) had significantly greater slowing in their walking speed from baseline to follow-up. Participants with long baseline sleep onset latency (≥30 minutes) had significant increases in mobility difficulties and time to complete chair stands. Sleep efficiency and wake after sleep onset were not significantly associated with any outcomes. No sleep predictors were associated with change in instrumental activities of daily living.

CONCLUSIONS

These findings add to the body of evidence showing links between poor sleep and subsequent declines in physical function. Further experimental research is needed to understand the mechanisms at play.

Bidirectional Associations Between Sleep Quality and Grip Strength and the Mediating Role of Depression: Evidence From Two Nationally Representative Cohorts

BACKGROUND

Although studies have demonstrated associations between sleep quality (SQ) and grip strength (GS) in older adults, the direction and underlying mechanisms of this relationship are yet to be better delineated. We aimed to longitudinally investigate the bidirectional association between SQ and GS and the mediating role of depression in this association.

METHODS

Based on 2 nationally representative samples with people aged ≥50 years from the China Health and Retirement Longitudinal Study (CHARLS; 4 200 participants) and English Longitudinal Study of Ageing (ELSA; 5 922 participants), cross-lagged panel models were employed to examine the potential bidirectional relationships between objectively measured GS and self-reported SQ.

RESULTS

We observed a GS-SQ bidirectional association dominated by GS. After adjusting for potential confounders, a higher GS at T1 predicted better SQ at T2 (ELSA: β = 0.075; CHARLS: β = 0.104, p < .001) and vice versa (ELSA: β = 0.034; CHARLS: β = 0.030, p < .01). Moreover, depression partially mediated the impact of GS on subsequent SQ (ELSA, indirect effect: 0.0057, 95% confidence interval [CI]: 0.0035-0.0084; CHARLS, indirect effect: 0.0086, 95% CI: 0.0051, 0.0131), but not vice versa.

CONCLUSIONS

The results regarding data from both cohorts consistently supported a bidirectional association between GS and SQ and the mediating role of depression in the dominant pathway of this bidirectional relationship. Older adults with a low GS should be made aware of a potentially vicious cycle related to depression that can affect their sleep. Regular screening for depression may help to break this cycle.

Sleep duration and depressive symptoms in Chinese middle-aged and older adults: The moderating effects of grip strength

BACKGROUND

Evidence on the combined effect of sleep duration and grip strength on depressive symptoms is scarce. This study aimed to explore the moderating effect of grip strength on the association between sleep duration and depressive symptoms in a large cohort of middle-aged and older adults.

METHOD

Data were extracted from the China Health and Retirement Longitudinal Study (CHARLS) 2011-2018 wave. Grip strength and sleep duration were assessed by dynamometer and self-report, respectively. Depressive symptoms were determined by the Centre for Epidemiological Studies Depression scale (CESD-10). Multivariable cox regression model was used to explore the associations between sleep duration, and depressive symptoms, and assess moderation by grip strength.

RESULTS

A total of 4337 participants aged 57.0 ± 8.1 years (45.1 % females) were included in this study. During the 7-year follow up period, 1508 participants developed depressive symptoms. Short sleep duration (<6 h/d) was significantly associated with an increased risk of depressive symptoms [Hazard ratio (HR):1.24, 95 % confidence interval (CI):1.09, 1.40)]. This association remained in individuals with the low (HR:1.22, 95%CI:1.00, 1.49) and middle grip strength (HR:1.32, 95%CI: 1.07, 1.63), but attenuated in individuals with high grip strength (HR:1.11, 95%CI: 0.86, 1.43).

CONCLUSIONS

High grip strength mitigated the association between short sleep duration and higher risk of depressive symptoms. Thus, improving sleep duration and strengthening muscle strength are recommended to prevent depressive symptoms in middle-aged and older adults.

Sleep duration affects the sequential change of body mass index and muscle strength: a contribution to dynapenic obesity

BACKGROUND

With aging, body mass index (BMI) increases and muscle strength declines, resulting in dynapenic obesity. It remains unknown whether and how sleep duration contributes to the sequence of BMI and muscle strength change in the progression of dynapenic obesity.

METHODS

Data were derived from the first two waves of China Health and Retirement Longitudinal Study. Sleep duration was self-reported. BMI was calculated and grip strength (GS) was measured to reflect muscle strength. The effect of baseline sleep duration on the sequential change of BMI and GS was assessed using two mediation models considering the nonlinear associations between them. The moderating effect of metabolic disorder was also tested.

RESULTS

Totally 4986 participants aged ≥ 50 years (50.8% females) with complete information on variables were included. Baseline BMI fully mediated the nonlinear association between sleep duration and follow-up GS change, but baseline GS did not mediate between sleep duration and follow-up BMI change for older men and women. Short sleep duration positively affected BMI-induced GS change (β = 0.038; 95%CI, 0.015-0.074), while this favorable effect became nonsignificant for moderate sleep duration (β = 0.008; 95% CI, -0.003-0.024) and turned negative with prolonged sleep duration (β =  - 0.022; 95%CI, - 0.051 to - 0.003). This nonlinear mediation effect was more pronounced in older women who are relatively metabolically healthy at baseline.

CONCLUSION

For older adults in China, the influence of sleep duration on BMI-induced GS change but not the GS-induced BMI change suggested the contribution of sleep duration to the sequential course in the progression of dynapenic obesity. Sleep duration deviated either above or below normal range may confer adverse impact on GS through BMI. Strategies addressing sleep and obesity jointly to improve muscle function and delay the progression of dynapenic obesity are required.

Association between Sleep Duration and Grip Strength in U.S. Older Adults: An NHANES Analysis (2011-2014)

Handgrip strength has been shown an indispensable biomarker for older adults. Furthermore, the association between sleep duration and grip strength in special populations (e.g., type 2 diabetics) has been previously documented. However, the association between sleep duration and grip strength has been less studied in older adults and the dose-response relationship is unclear. Therefore, we drew 1881 participants aged 60 years and older from the National Health and Nutrition Examination Survey (NHANES) 2011-2014 to explore their association and the dose-response relationship. Sleep duration was obtained through self-report. Grip strength data were obtained through a grip test using a handgrip dynamometer and divided into two categories: low grip strength and normal grip strength. Thus, dichotomized grip strength was used as a dependent variable. Poisson regression and restricted cubic spline were used for the main part of the analysis. We found that long sleep duration (≥9 h) was associated with a higher prevalence of low grip strength than the normal sleep duration (7-<9 h) group (IRR: 1.38, 95% CI: 1.12-1.69). Moreover, the gender-stratified analysis did not change the original results. This association was particularly pronounced and further strengthened among participants with normal weight (BMI < 25) (IRR: 2.30, 95% CI: 1.64-3.22) and participants aged 60-70 (IRR: 1.76, 95% CI: 1.40-2.22). In addition, with the increase in sleep duration, the multivariate-adjusted IRRs of low grip strength had a general downward trend at first, followed by a brief period of stability, and then presented an upward trend (p-value for non-linearity = 0.001). According to this study, we found that older adults who had long sleep duration had a higher risk of low grip strength. Muscle insulin utilization and muscle glucose metabolism are closely related to grip strength, so our research emphasizes the importance of maintaining normal sleep duration in older adults and suggests that older adults who sleep for a long period should pay more attention to their muscle health.

Sleep and Anabolic/Catabolic Hormonal Profile in Sedentary Middle-Aged Adults: The FIT-AGEING Study

Sleep quality plays an important role in the modulation of several aging markers. This influence could be explained by aging-induced hormonal changes. Indeed, poor sleep quality has been associated with the development of several endocrine-related health complications. This study examined the relationship of both subjective and objective sleep quantity and quality, with basal levels of selected plasma anabolic and catabolic hormones in sedentary middle-aged adults. A total of 74 volunteers (52.7% women; aged 53.7 ± 5.1) were recruited for this study. Subjective sleep quality was assessed by the Pittsburgh Sleep Quality Index (PSQI; higher scores indicate worse sleep quality), and objective sleep quality parameters (total sleep time [TST], wake after sleep onset [WASO], and sleep efficiency [SE]) were measured using a wrist-worn accelerometer. Basal levels of plasma dehydroepiandrosterone sulphate (DHEAS), total testosterone, sex hormone binding globulin (SHBG), somatotropin, and cortisol levels, were determined. Free testosterone was calculated from the total testosterone and SHBG levels. No associations of global PSQI score, TST, WASO, and SE with DHEAS, free testosterone, and somatotropin plasma levels were found, neither in men nor in women (all p ≥ 0.05). Global PSQI score was inversely related to cortisol plasma levels in women (p = 0.043). WASO was positively associated with cortisol plasma levels, while SE was negatively associated with cortisol plasma levels in women (all p ≤ 0.027). Sleep quality is not related to levels of plasma anabolic hormones, but to levels of catabolic hormones, in sedentary middle-aged adults. Therefore, these results suggest that potential changes in aging biomarkers associated with sleep disturbances, could be mediated by age-related changes in the catabolic endocrine system.

Association between Sleep Duration and Hand Grip Strength among COPD Patients

This study aimed to evaluate the association between night-time sleep duration and hand grip strength (HGS) among patients with chronic obstructive pulmonary disease (COPD). Participants aged ≥45 years were included in a nationally representative investigation clinical study in 2015. HGS was measured using dynamometers. The data on night-time sleep duration, sociodemographic information, and health-related variables were systematically collected. For analysis, sleep duration was categorized as <5 h, 5-7 h, 7 h, 7-9 h, and >9 h. Multivariable linear regression models were used to determine the possible association between the night-time sleep duration and HGS. Our results indicated that the shortest (<5 h) or the longest sleep duration (>9 h) was relevant to high risk of weaker HGS in females. In males, the shortest (<5 h) sleep duration was correlated to lower HGS. Thus, our findings clearly suggest that health care providers should focus on the potential influence of sleep duration on HGS among COPD patients.

Higher Handgrip Strength Is Linked to Better Cognitive Performance in Chinese Adults with Hypertension

Objective: There is growing evidence that in adults, higher levels of handgrip strength (HGS) are linked to better cognitive performance. However, the relationship between HGS and cognitive performance has not been sufficiently investigated in special cohorts, such as individuals with hypertension who have an intrinsically higher risk of cognitive decline. Thus, the purpose of this study was to examine the relationship between HGS and cognitive performance in adults with hypertension using data from the Global Ageing and Adult Health Survey (SAGE). Methods: A total of 4486 Chinese adults with hypertension from the SAGE were included in this study. Absolute handgrip strength (aHGS in kilograms) was measured using a handheld electronic dynamometer, and cognitive performance was assessed in the domains of short-term memory, delayed memory, and language ability. Multiple linear regression models were fitted to examine the association between relative handgrip strength (rHGS; aHGS divided by body mass index) and measures of cognitive performance. Results: Overall, higher levels of rHGS were associated with higher scores in short-term memory (β = 0.20) and language (β = 0.63) compared with the lowest tertiles of rHGS. In male participants, higher HGS was associated with higher scores in short-term memory (β = 0.31), language (β = 0.64), and delayed memory (β = 0.22). There were no associations between rHGS and cognitive performance measures in females. Conclusion: We observed that a higher level of rHGS was associated with better cognitive performance among hypertensive male individuals. Further studies are needed to investigate the neurobiological mechanisms, including sex-specific differences driving the relationship between measures of HGS and cognitive performance in individuals with hypertension.

Determinants of Self-Rated Health Among Middle-Aged and Elderly Patients with COPD: The China Health and Retirement Longitudinal Study

This study aimed to assess self-rated health (SRH) status and its determinants in patients with chronic obstructive pulmonary disease (COPD). Participants aged at least 45 years were included from a nationally representative investigation in 2015. The SRH assessment was divided into two groups: "good" and "not good." Independent samples t-tests, chi-square tests, and Fisher's exact tests were used to determine differences in patient characteristics between the two groups. Multiple logistic models were used to determine factors influencing SRH. A total of 1,215 patients with COPD were included in the final analysis, of whom 21.2% reported favorable SRH status. The results indicated that female gender, non-smoking, and elevated peak expiratory flow correlated with better SRH, while nighttime sleep duration less than 7 hours, asthma, and disability, negatively impacted SRH. Our findings provide new evidence for the development of effective health promotion programs for the well-being of patients with COPD.

Associations between longitudinal trajectories of insomnia symptoms and sleep duration with objective physical function in postmenopausal women: the Study of Women's Health Across the Nation

STUDY OBJECTIVES

Examine the association between trajectories of self-reported insomnia symptoms and sleep duration over 13 years with objective physical function.

METHODS

We utilized data from 1627 Study of Women's Health Across the Nation (SWAN) participants, aged 61.9±2.7 y at the end of the 13-y follow-up. Latent class growth models identified trajectories of insomnia symptoms (trouble falling asleep, frequent night-time awakenings, and/or early-morning awakening) and sleep duration over 13 y. Physical function tests were performed at the end of the 13-y period: 40-ft walk, 4-m walk, repeated chair stand, grip strength, and balance. Multivariable regression analyses examined each physical function measure according to the insomnia symptom or sleep duration trajectory group.

RESULTS

Five insomnia symptom trajectories and two sleep duration trajectories were identified. Women with a consistently high likelihood of insomnia symptoms and women with a decreased likelihood of insomnia symptoms (i.e., improving) had slower gait speed (3.5% slower 40-ft walk [consistently high], 3.7% slower 4-m walk [improving]; each P≤.05) than those with a consistently low likelihood of insomnia symptoms. In contrast, women with a steep increase in the likelihood of insomnia symptoms over time and women with persistent insufficient sleep duration had lower odds of having a balance problem (odds ratio [OR]=0.36 and OR=0.61, respectively; each P<.02) compared to those with a consistently low likelihood of insomnia symptoms and those with persistent sufficient sleep duration, respectively.

CONCLUSION

These results suggest that women's sleep during midlife has important implications for maintaining physical function during the transition into older adulthood.

Role of physical activity and fitness on sleep in sedentary middle-aged adults: the FIT-AGEING study

The association of physical activity and fitness with sleep still remains unclear since there is a lack of studies in this field of research using objective measurements of these variables. This study aimed to investigate the association of objectively-measured sedentariness, physical activity levels, and physical fitness with sleep quantity and quality in sedentary middle-aged adults. A total of 74 volunteers (52.7% women; aged 53.7 ± 5.1) were recruited for the present study. Cardiorespiratory fitness was measured through a maximal treadmill test, and muscular strength by extension and flexion peak torque, and by the hand grip test. Physical activity and objective sleep parameters were determined through accelerometry, and subjective sleep by the Pittsburgh Sleep Quality Index (PSQI). Reduced levels of sedentariness, greater VO_2max, and greater muscular strength were positively related to improved objective sleep quantity and quality (all P ≤ 0.05). Furthermore, higher levels of overall physical activity, VO_2max, and muscular strength were related to better subjective sleep quantity and quality (all P ≤ 0.05). Reduced sedentariness and increased physical activity and fitness may be a potential prevention and/or treatment pathway to reduce sleep disturbances and, in general, to improve patients physical and psychological health for a successful aging process.

Association between muscle strength and sleep quality and duration among middle-aged and older adults: a systematic review

PURPOSE

To examine the relationship between sleep quality and duration and muscle strength among community-dwelling middle-aged and older adults.

METHODS

A systematic review was conducted from March 2020 until May 2020. Searches were done for peer-reviewed and English-written articles reporting results of studies in PubMed, Embase, Scopus, Cochrane Library, and in article references lists. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses was used as well as the Newcastle-Ottawa Scale (NOS) to appraise the methodological quality.

RESULTS

Twenty-one cross-sectional, three prospective studies and a total of 92,363 subjects were included. The majority of the included studies are classified as "high quality". Handgrip strength is the main method of muscle strength assessment. Sleep assessment is usually conducted using subjective measures, such as validated sleep scales or self-reported questionnaires. Actigraphy, as an objective measure, is used less often. Most studies support strong evidence on the association between weak muscle strength and poor sleep quality and duration among middle-aged and older adults; whereas the results for the gender-specific association and the impact of short or long sleep duration were inconclusive.

CONCLUSION

This review has identified strong evidence on the relationship between sleep quality and duration and muscle strength among middle-aged and older adults. Health professionals should consider this relationship as a component of geriatric assessment in community practice and geriatric settings. Future rigorous research with a combination of subjective and objective measurements is needed to explore whether gender and specific sleep duration are related to muscle strength.

Association between muscle strength and depressive symptoms among Chinese female college freshmen: a cross-sectional study

Background

Increased physical activity level is related to lower risk of depressive symptoms, and there is an inverse association between muscle strength and risk of depressive symptoms among the elderly. Although there is evidence of an inverse association between muscle strength and depressive symptoms, the relationship between these variables in a younger population is still unknown. This study aimed to examine the association between handgrip strength, a representative indicator of skeletal muscle strength, and the risk of depressive symptoms among Chinese female college freshmen.

Methods

A cross-sectional study was conducted among 867 participants aged between 16 and 23 years. Handgrip strength was measured with a handheld digital Smedley dynamometer, and handgrip strength relative to body weight (kg/kg) was calculated and was classified into tertiles as follows: low (0.32–0.50), medium (0.51–0.58), and high (0.59–0.94). Depressive symptoms were evaluated using the 20-item Zung self-rating depression scale (SDS), and three cutoff points were used to indicate different depression levels.

Results

We found that 10.7% of participants were classified as having severe depressive symptoms using an SDS score of 50 as the cutoff point. After adjusting for potential confounders, the adjusted odds ratios and 95% confidence intervals (CIs) for moderate-to-severe depressive symptoms across tertiles of the relative handgrip strength were 1.00 (reference) for tertile 1, 0.614 (0.353, 1.069) for tertile 2, and 0.537 (0.292, 0.988) for tertile 3 (P for trend = 0.041). The significant associations remained when other cutoff points (SDS scores: 48 or 45) were used. Interactions between handgrip strength and potential confounders for depressive symptoms in the final models were not significant.

Conclusions

Our findings indicate that handgrip strength is inversely and independently related to the risk of depressive symptoms among Chinese female college freshmen. The present findings can help develop an effective intervention strategy against depression. Further intervention studies are needed to explore the mechanisms underlying the effects of handgrip strength on depressive symptoms.

Associations of physical fitness and physical activity with sleep among middle-aged women

BACKGROUND

Sleep is an important component of health. Sleep disturbances increase in women as they enter menopause. Physical activity has been associated with improved sleep among older populations. The purpose of this study was to determine if physical activity and/or physical fitness are associated with sleep quantity and quality in middle-aged women.

METHODS

This study recruited 114 healthy women, aged 30-55 (43±8 y) from Saskatoon, Saskatchewan, from 2015-2019. Sleep quantity and quality were evaluated. Participants were classified on their aerobic fitness, based on estimated peak aerobic capacity, as high or low grip strength and, as active or inactive.

RESULTS

The high aerobic fitness group had a greater mean sleep duration of 7.04±1.02 h compared to the low fit group 6.61±1.00 h after adjusting for age, Body Mass Index, waist circumference and menstrual status (P=0.01). The percentage of high aerobic fitness women who felt rested was greater than low aerobic fitness women (67±6% vs. 45±7%, P=0.03), after adjusting for age, Body Mass Index, waist circumference and menstrual status. Our study found a significant difference between women with higher aerobic fitness levels getting more sleep each night and feeling more rested.

CONCLUSIONS

The continued examination of physical fitness and its relationship to sleep holds importance for women's health.

Factors associated with low handgrip strength in older people: data of the Study of Chronic Diseases (Edoc-I)

BACKGROUND

Handgrip strength (HGS) is an important health biomarker whose low scores have been shown to be associated with the morbimortality. This study aimed to analyze the factors associated with low HGS in older people in Rio Branco, Acre, Brazil.

METHODS

The study was carried out with data from the Study of Chronic Diseases (EDOC-I) - Older People, a cross-sectional household PAPI probability sample survey performed with 1016 people aged over 60 residing in Rio Branco in 2014. The low HGS was defined by the 20th percentile of the maximum HGS by sex and age group. Associations between variables of health status (psychological and physical) and low HGS, by sex, were estimated using logistic regression, expressed by adjusted ORs (aOR).

RESULTS

Older individuals had lower median HGS than younger individuals (- 6.0 kg among men and - 2.6 kg among women). Women aged over 80 had, on average, the lower quintile of HGS compared to women of the previous age groups. Factors independently associated with low HGS in men and women, respectively, were low weigh in body mass index [(aOR = 2.80; 95%CI: 1.19, 6.61) and (aOR = 2.61; 95%CI: 1.46, 4.66)], anemia [(aOR = 4.15; 95%CI: 2.09, 8.21) and (aOR = 1.80; 95%CI: 1.06, 3.06)] and diabetes as a risk factor in men (aOR 1.95; 95%CI: 1.00, 3.81). There was a higher chance of low HGS in men with partners (aOR = 2.44; 95%CI: 1.32, 4.51), smokers or former smokers (aOR = 3.25; 95%CI: 1.25, 8.44), with current self-assessment of health worse than the 12 previous months (aOR = 2.21; 95%CI: 1.14, 4.30) and dependence in activities of daily living (aOR = 2.92; 95%CI: 1.35, 6.30). Only among women, there was an increased chance of low HGS associated with altered waist-to-hip ratio (aOR = 1.79; 95%CI: 1.02, 3.12), insomnia (aOR = 1.83; 95%CI: 1.10, 3.03) and physical activity from displacement/occupation (aOR = 1.75; 95%CI: 1.08, 2.84).

CONCLUSION

Factors associated with low HGS are not the same between sexes, and the inclusion of HGS as a component of health assessment seems to be a promising strategy for disease prevention and health promotion.

Loneliness and sleep in older adults

PURPOSE

The present analysis aims to examine if loneliness is associated with sleep problems and duration over a 4-year period in a sample of older adults aged 50 years and over.

METHODS

Data on loneliness, sleep duration, sleep problems and covariates were obtained from 5698 participants from the English Longitudinal Study of Ageing at baseline (wave 4) and follow up (wave 6).

RESULTS

Following adjustment for covariates, baseline loneliness was associated with an increase in the odds of reporting short sleep, and more sleep problems at follow up.

CONCLUSIONS

Short sleep may represent an important mechanism through which loneliness affects health.

Associations of OSA and Nocturnal Hypoxemia with Strength and Body Composition in Community Dwelling Middle Aged and Older Men

PURPOSE

Reduced hand grip strength (HGS) is associated with poorer health in chronic conditions, yet there has been little research examining the association with hand grip strength and obstructive sleep apnea (OSA). Further, these studies have not examined, nor adjusted, for muscle mass. The aim of this study was to determine associations between OSA indices, HGS, muscle mass, and fat mass.

PARTICIPANTS AND METHODS

A total of 613 participants (age range 41-88, BMI 28.6 ± 4.3) from the population-based Men Androgen Inflammation Lifestyle Environment and Stress Study underwent in-home overnight polysomnography, assessment of dominant and non-dominant HGS, and dual x-ray absorptiometry to determine whole body muscle mass and fat mass. Linear models determined cross-sectional associations of polysomnographic-derived OSA indices with hand grip strength, muscle mass, and fat mass, whilst adjusting for lifestyle information (income, smoking status, diet, self-reported physical activity), blood sample derived testosterone and systemic inflammation (C-reactive protein), cardiometabolic health (cardiovascular disease, hypertension, type 2 diabetes), and depression.

RESULTS

In adjusted models, reduced dominant HGS was associated with lower oxygen nadir (unstandardised β [B] = 0.19, 95% confidence interval [CI] 0.08 to 0.29), greater time spent below 90% oxygen saturation (B = -0.08, 95% CI -0.14 to -0.02), and increased apnea duration (B = -0.3, 95% CI -0.23 to -0.02). By contrast, there were no associations between HGS and both AHI and REM AHI. Fat mass was consistently associated with worsening OSA indices, whereas muscle mass demonstrated no associations with any OSA index.

CONCLUSION

Our findings suggest impairments in HGS may be related to fat infiltration of muscle, hypoxemia-induced reductions in peripheral neural innervation, or even endothelial dysfunction, which is a common outcome of hypoxemia. Longitudinal data are needed to further examine these hypotheses and establish if reduced grip strength in patients with OSA is associated with long-term adverse health outcomes.