Relationship of body mass index with frailty and all-cause mortality among middle-aged and older adults.

BACKGROUND: Parallel to growth of aging and obese populations, the prevalence of metabolic diseases is rising. How body mass index (BMI) relates to frailty and mortality across frailty levels is controversial. We examined the associations of high BMI with frailty and mortality and explored the effects of percent body fat on these associations. METHODS: We included 29,937 participants aged ≥50 years from the 2001-2006 National Health and Nutrition Examination Survey (NHANES) cohorts (N=6062; 53.7% females) and from wave 1 (2004) of Survey of Health, Ageing and Retirement in Europe (SHARE) (N=23,875; 54% females). BMI levels were categorized as: normal: 18.5-24.9 kg/m2, overweight: 25.0-29.9, obese grade 1: 30.0-34.9, and obese grade 2 or 3: >35.0. A frailty index (FI) was constructed excluding nutrition-related items: 36 items for NHANES and 57 items for SHARE. We categorized the FI using 0.1-point increments: FI ≤ 0.1 (non-frail), 0.1 < FI ≤ 0.2 (very mildly frail), 0.2 < FI ≤ 0.3 (mildly frail), and FI > 0.3 (moderately/severely frail). Percent body fat was measured using DXA for NHANES participants. All-cause mortality data were obtained until 2015 for NHANES and 2017 for SHARE to estimate 10-year mortality risk. All analyses were adjusted for age, sex, educational, marital, employment, and smoking statuses. RESULTS: Mean age of participants was 63.3±10.2 years for NHANES and 65.0±10.0 years for SHARE. In both cohorts, BMI levels ≥25 kg/m2 were associated with higher frailty, compared to normal BMI. In SHARE, having a BMI level greater than 35 kg/m2 increased mortality risk in participants with FI≤0.1 (HR 1.31, 95%CI 1.02-1.69). Overweight participants with FI scores >0.3 were at lower risk for mortality compared to normal BMI [NHANES (0.79, 0.64-0.96); SHARE (0.71, 0.63-0.80)]. Higher percent body fat was associated with higher frailty. Percent body fat significantly mediated the relationship between BMI levels and frailty but did not mediate the relationship between BMI levels and mortality risk. CONCLUSIONS: Being overweight or obese is associated with higher frailty levels. In this study, we found that being overweight is a protective factor of mortality in moderately/severely frail people and obesity grade 1 may be protective for mortality for people with at least a mild level of frailty. In contrast, obesity grades 2 and 3 may be associated with higher mortality risk in non-frail people. The relationship between BMI and frailty is partially explained by body fat.

Exploring the Association of a Total Physical Activity Energy Expenditure and Diabetes Mellitus in Adults: A Cross-Sectional Analysis of the Canadian Health Measures Survey.

Background: Physical activity (PA) guidelines for adults recommend participation in aerobic activities of moderate-to-vigorous intensity and a minimum of two sessions of resistance training (RT) weekly. These guidelines account for a small amount of the total PA energy expenditure and include no recommendation for low intensity activities (sleeping, sedentary behavior, and light intensity PA). Consequently, there is a need to investigate the benefits of total PA energy expenditure and diabetes mellitus (DM); to investigate the association between total PA energy expenditure and DM in adults aged 45 years or above. Methods: Data from the Canadian Health Measures Survey (CHMS; n = 5591) were used for the cross-sectional analysis. DM was measured using hemoglobin glycated (A1c) and questionnaires in adults aged 45 and above. PA and sedentary behavior were estimated using accelerometry. Sleep and RT were self-reported. Total PA energy expenditure was computed using the sum of metabolic equivalent of task-min/week. Results: The mean age of the sample was 58.0 ± 0.2 years old. No associations were observed between total PA energy expenditure and self-reported T2DM in all models (P > 0.05). For objectively measured DM, this association was significant when adjusted for age, sex, ethnicity, and smoking [OR: 0.45; 95% CI (0.25-0.80)]; however, the association was no longer significant once adjusted for waist circumference and further adjusted for meeting the International PA Guidelines [OR: 0.64; 95% CI (0.33-1.27)] (P > 0.05). Conclusion: Total PA energy expenditure performed weekly is not associated with DM when considering other known risk factors, including waist circumference and meeting the PA guidelines.

Association between physical function and various patterns of physical activity in older adults: a cross-sectional analysis.

BACKGROUND: To improve physical function, physical activity (PA) guidelines for older adults recommend completing PA in bouts of 10 min or more. Spontaneous PA (< 10 min) can also benefit older adults. However, a paucity of research exists examining if shorter bouts of PA are associated with greater physical function. AIM: To determine the association between various patterns of PA and the likelihood of greater physical function in older adults. METHODS: Older adults from the 2003-2004 and 2005-2006 cycles of the National Health and Nutrition Examination Survey were included for analysis. PA lasting 1, 5, 10, 30, and 60 min was quantified using accelerometers. Physical function was assessed using a Likert scale reflecting the self-reported capability to complete 11 tasks. A single function score was then computed using factor analysis. Logistic regression analyses calculated the association between PA bout length and the likelihood of above average function. RESULTS: PA performed in 1-min (odds ratio [OR] 1.02; 95% confidence interval [CI] 1.01-1.03), 5-min (OR 1.02; CI 1.01-1.03), or 10-min bouts (OR 1.02; CI 1.01-1.03) was associated with greater physical function following adjustment for confounders. When scaled to represent an accumulation of 10 min of MVPA, likelihoods increased for both 1-min ([OR] 1.25; 95% [CI] 1.11-1.39) and 5-min (OR 1.22; 95% CI 1.08-1.37) bouts. DISCUSSION/CONCLUSIONS: Our findings suggest bouts of PA lasting 10 min or shorter in duration are associated with greater physical function in older adults.