Tung Wai Auyeung

Aims: Studies about sarcopenia in Asia are fewer, and started later than in Europe and America. We attempted to examine the decline in muscle mass, grip strength and gait speed in a cohort of older Chinese prospectively over 4 years.Methods: We recruited 4000 community‐living Chinese older than 64 years, and measured their appendicular skeletal mass (ASM) by dual‐energy X‐ray absorptiometry, grip strength, and gait speed at baseline and after 2 years. Muscle mass and gait speed were additionally measured after 4 years.Results: After 4 years, 3018 participants completed all the measurements. The annualized decline in grip strength (−0.798 kg/year vs −1.239 kg/year) and gait speed (−0.019 m/s/year vs – 0.025 m/s/year) was faster in women than in men. Muscle mass was relatively preserved in comparison with grip strength and gait speed. The percentage loss of ASM in 4 years was −1.59% and −2.02% in men and women, respectively. The percentage decline in gait speed after 4 years was −8.2% in men and −9.0% in women. However, the decline in grip strength was more rapid, particularly in women, which was −10.0% in 2 years and less so in men, −3.85% in 2 years.Conclusion: Compared with black people and white people, the older Chinese have less muscle mass, weaker grip strength and slower gait speed. Although the rate of loss of ASM was modest, the decline in gait speed was rapid and the decline in grip strength was particularly fast in older Chinese women. Geriatr Gerontol Int 2014; 14 (Suppl. 1): 76–84.

Conventionally, sarcopenia is defined by muscle mass and physical performance. We hypothesized that the disability caused by sarcopenia and sarcopenic obesity was related to the amount of adiposity or body weight bearing on a unit of muscle mass, or the adiposity to muscle ratio. We therefore examined whether this ratio could predict physical limitation by secondary analysis of the data in our previous study. We recruited 3,153 community-dwelling adults aged >65 years and their body composition was measured by dual-energy X-ray absorptiometry. Assessment of physical limitation was undertaken 4 years later. The relationship between baseline adiposity to muscle ratio and incident physical limitation was examined by logistic regression. In men, the adiposity to muscle ratios, namely total body fat to lower-limb muscle mass, total body fat to fat-free mass (FFM), and body weight to FFM, were predictive of physical limitation before and after adjustment for the covariates: age, Mini-mental Status Examination score, Geriatric Depression Scale score >8, and the diagnosis of chronic obstructive pulmonary disease, diabetes mellitus, hypertension, heart disease, and stroke (all p values < 0.001), when the total body fat to lower-limb muscle mass ratio was greater than or equal to 0.75. In women, throughout the entire range of that ratio, all three adiposity to muscle ratios were associated with physical limitation 4 years later both before and after adjustment for the same set of covariates (all p values < 0.05). Sarcopenia and sarcopenic obesity as measured by the body weight or adiposity bearing on a unit of muscle mass (the adiposity to muscle ratio) could predict incident or worsening physical limitation in older women across the entire range of the total body fat to lower-limb muscle mass ratio; and in older men when this ratio was equal to or greater than 0.75.

This study aims to examine the phase advance of sleep–wake rhythm, napping habit, nocturnal sleep duration, prolonged sleep latency and insomnia and their relationship with cognitive function. This is a cross-sectional study. Participants in this study are 2,947 community-dwelling adults older than 65 years old. Measurements of mini-mental examination (MMSE) score, go-to-bed time, wake-up time, nocturnal sleep duration, prolonged sleep latency, napping, and insomnia were done. The mean (standard deviation) nocturnal sleep hours was 7.96 (1.39) h. Twenty-one percent and 16.2% of the participants complained of prolonged sleep latency longer than 1 h and insomnia, respectively. Fifty-six percent of the participants napped once or more than once weekly. With advancing age, the participants reported longer sleep duration (p < 0.001), went to bed earlier, and woke up earlier, which were significant both before and after adjustment. The participants who had lower MMSE score went to bed earlier and woke up earlier, which were statistically significant both before and after adjustment. An inverted U-shaped relationship was observed between MMSE score and napping frequency, p for tend 0.026.The MMSE score decreased when the sleep duration prolonged from 7 h to ≧10 h (p for trend 0.006). No trend was observed from the sleep duration p for trend 0.500). Modest age-independent phase advance of the sleep–wake rhythm is associated with lower cognitive function. Whether this is a manifestation of early pre-clinical dementia and whether its recognition with early stabilization can slow cognitive decline remain elusive.

In contrast to that in the middle-aged, higher body mass index (BMI) in older people is associated with higher survival rates. Yet, BMI makes no distinction between fat elsewhere and abdominal fat, the latter being metabolically more harmful. We hypothesized that overall adiposity might be protective in old age, but that central fat might offset that benefit and remained harmful as in the middle-aged. Three thousand nine hundred seventy-eight Chinese elderly ≥65 years had demographics, medical conditions, physical activity, and body composition by DXA recorded at baseline. Overall adiposity was measured as whole body fat%, and abdominal adiposity as waist circumference, waist–hip ratio, and relative abdominal fat (RAF) (relative abdominal fat = abdominal fat according to anatomical landmarks/whole body fat). Deaths within 1 year from baseline were excluded from analysis. All-cause and cardiovascular mortality were analyzed using Cox regression, adjusted for covariates. The lowest quintile of adiposity measurements was used for comparison. After a mean follow-up of 72.3 months, 13.7% men and 4.5% women had died. In men, the highest two quintiles of whole body fat % and the upper four quintiles of RAF were associated with significantly lower all-cause mortality, and adjusted hazard ratio (95% CI) in ascending quintiles of RAF compared with the lowest quintile was 0.62 (0.43–0.89), 0.58 (0.4–0.85), 0.52 (0.36–0.77), and 0.67 (0.47–0.96). No relationship was found between abdominal adiposity and cardiovascular mortality in both genders. Higher whole body fat % as well as higher proportion of abdominal fat was associated with lower all-cause mortality in men. No such relation was found in women.

Background: height loss beginning in mid-life and post-menopausal period was associated with adverse health outcomes. However, height loss occurring after old age has been little studied. We examined how height loss was related to bone mineral density (BMD) change, fracture incidence and cause-specific mortality in older adults. Methods: the stature and BMD of 3145 community-dwelling men and women aged ≥65 were measured at baseline and after 4 years. All fracture and cause-specific mortality events were searched in a territory-wide clinical information database and death registry. Results: twenty-five (1.6%) men and 64 (4.0%) women lost >2 cm after 4 years. In women, the BMD decline was faster in the rapid height losers (adjusted difference = 4.18%, P < 0.001). There was no corresponding difference observed in men. Rapid height loss was associated with excess all fractures and hip fractures (adjusted HR for all fractures = 2.86, P < 0.001; adjusted HR for hip fractures = 4.74, P < 0.01) in women but only hip fractures (adjusted HR = 4.93, P < 0.05) in men. The all-cause (adjusted HR = 3.43, P < 0.01) and respiratory disease mortality (adjusted HR = 5.64, P < 0.05) were higher in men with rapid height loss, whereas those in women were insignificant. Conclusions: modest height loss occurring after old age, >2 cm in 4 years, was associated with excess hip fracture, total and respiratory disease mortality in older men. In women, it was associated with excess BMD decline, all fractures and hip fractures but not mortality. Further research is needed to determine the usefulness of regular stature measurement as an indicator of bone health in the primary-care setting in older adults.