Correlates of HandGrip Strength and Activities of Daily Living in Elderly Sri Lankans

To the Editor: Sri Lanka is one of the most rapidly aging countries in Asia. As life expectancy continues to increase, projected to reach 71.1 for men and 80.8 for women by 2016,1 it is important to better understand which factors affect the health of its elderly population. Handgrip strength (HGS) and activities of daily living (ADLs) are measures of physical strength and functional capability that are correlated with overall health in elderly adults.2 Sex, age, education, psychological distress, cognitive function, self-rated health (SRH), and comorbidities have frequently been associated with HGS and ADL in Western populations,3-5 but it is unclear whether these associations are present in Sri Lanka's elderly adults, especially because ethnic differences have been found in previous studies,6 and no studies have assessed these associations in this population. Therefore, the aim of the current study was to determine the extent to which characteristics found to be significant predictors of HGS and ADL in other populations are also important correlates in elderly Sri Lankans. A cross-sectional survey was conducted in 252 individuals aged 60 to 92 living in the Galle district of Sri Lanka. Outcome measures were HGS (measured using a handgrip meter) and ADL score (sum of instrumental and basic ADL scores, range 0–28, higher scores indicating better functional capability). Eight potential correlates of HGS and ADL (sex, education (≤ vs >secondary school), age, cognitive function (Montreal Cognitive Assessment (MoCA)), psychological distress (Kessler Psychological Distress Scale), recent injury (yes vs no), number of physical illnesses, and SRH (very good, good, moderate, bad, very bad) were assessed according to self-report. Potential correlates were assessed using multivariate linear regression analysis (forward selection method). Mean age was 71.7 ± 8.2, 67% were female, 67% had a secondary level education or less, 23% had suffered an injury in the last 60 days, and 48% rated their health to be moderate and 31% bad. There was a positive correlation between HGS and ADL score (correlation coefficient = 0.5, P < .001). Table 1 shows the results of the multivariate analyses. Model A, which included only the significant correlates of HGS, shows that better SRH was positively correlated with HGS. Model B, which included only the significant correlates of ADLs, shows that psychological distress is negatively correlated with ADL function. Both models show that age is a significant negative correlate and cognitive function a significant positive correlate of HGS and ADL. As previously reported, HGS and ADL score were significantly correlated with each other.2 Of the significant correlates of HGS and ADL, cognitive function, SRH, and psychological distress are to some extent modifiable. One explanation for the association between low HGS and poor cognitive function is the presence of shared pathogenesis, such as oxidative stress and high inflammatory markers, which may contribute to muscle loss and cognitive decline.7 Assessment of inflammatory markers could be a potential target of intervention. Another possible explanation for this association is difficulty with comprehension, which could also explain the association between ADL and cognitive function because some of the tasks (e.g., managing finances) require complex cognitive processes to perform.8 A possible explanation for the association between SRH and HGS is that SRH could better capture disease conditions than other variables (e.g., number of illnesses) because it takes into account a broader range of information (e.g., disease symptoms) that could be excluded using standardized measures.9 Regarding psychological distress and its association with ADLs, it is possible that symptoms caused by psychological distress (e.g., insomnia and fatigue), could increase susceptibility to disease and lead to functional decline over time.10 Empirical evidence has pointed to the risks and protective factors for psychological distress, which fall into three categories, sociodemographic and stress-related factors (e.g., poverty) and personal resources (e.g., income).10 Improvement of these factors could help alleviate symptoms of psychological distress and ultimately mitigate its adverse effects on functional capability. Although its small sample size and cross-sectional design limit this study, to the knowledge of the authors, it is the first conducted in elderly adults in Sri Lanka on HGS and ADL and their correlates. Given Sri Lanka's increasing life expectancy, rapidly growing elderly population, and limited resources, there is value in encouraging policy-makers to emphasize maintaining cognitive function and SRH and reducing psychological distress in Sri Lanka's elderly adults. We are thankful to the National Institutes of Health/Fogarty IC (R21 TW009151) for funding the research upon which this article is based. Conflict of Interest: The editor in chief has reviewed the conflict of interest checklist provided by the authors and has determined that the authors have no financial or any other kind of personal conflicts with this paper. Author Contributions: All authors: concept and design or analysis and interpretation of data, drafting of the article or revising it critically for important intellectual content, and final approval of the version to be published. Sponsor's Role: The sponsors had no role in the concept, design, analysis, interpretation of data, or in the drafting, revising, or final approval of the version to be published.