Grip Strength as a Marker of Ageing and Health: Evidence from Six Low - PDF document

Grip Strength as a Marker of Ageing and Health: Evidence from Six Low and Middle- Income Countries By P. Arokiasamy and Y. Selvamani Abstract Grip strength is a widely accepted marker of ageing and health. While chronological age is well recognized as a marker of frailty, many studies have investigated the close association between grip strength and frailty. Other studies have shown grip strength as a predictor of disability, morbidity and mortality. The objective of this paper is to assess the association between grip strength, overall and specific dimensions of multidimensional health such as functional loss, general health, cognition, chronic multimorbidity conditions and quality of life among older adults in age 50+. Cross-country analysis is conducte d using the WHO‟s Study on global AGEing and adult health (SAGE) data for Low and Middle-Income Countries (LMICs) of China, China, Ghana India, Mexico, Russia and South Africa. Regression models are estimated to predict the association between grip strength, functional health, multimorbidity, cognition and quality of life incorporating age, health risk factors and SES covariates. Results showed prevalence of morbidity and multi-morbidity conditions are associated with reduced grip strength. Regression analysis revealed significant association of multimorbidity conditions with grip strength in these six countries. Moreover, this association is stronger and consistent among men. We observed a strong association between grip strength and subjective health measures and cognition. Background Low and middle income countries (LIMCs) currently experience high speed of population aging. Consequently, the burden of NCDs is escalating; previous research indicates that NCDs have a disproportionately high impact on low- and middle-income countries. The implications of aging on health and health care are major public health challenge across globe. Aging has greatly contributed to steep increase in the prevalence of chronic morbidity and frailty. Grip strength is a widely accepted marker of ageing and health. While chronological age is well recognized as a marker of frailty, many studies have investigated the close association between grip strength and frailty. Other studies have shown grip strength as a predictor of disability, 1 | P a g e

morbidity and mortality (Giampaoli et al., 1999; Al Snih et al., 2004; Gale et al., 2005; Newman et al., 2006; Leong et al., 2015). Studies have shown combination of one or more diseases, also termed as multimorbidity is a major risk factor for individual survival and quality of life. Multimordity is referred as the presence of one or more morbidity conditions which has strong implication on the health care expenditure (Lee et al., 2015). Multimorbidity has been associated with adverse health outcomes, such as reduced physical function, poor quality of life, poor self-rated health (SRH), increased use of inpatient and ambulatory care and mortality. While, many studies have examined the association of multimorbidity with subjective health, mortality and quality of life (Marengoni et al., 2008; Garin et al., 2014; Arokiasamy et al., 2015), relatively, much less is known about the association of grip strength with ageing and health in LMICs. This study has two objectives; first, to examine the association between multimorbidity and grip strength. Secondly, to study the association of grip strength with the health and quality of life outcomes to understand the role of physical strength in determining later life general health and cognition. Muscle weakness in old age is associated with morbidity and mortality (Rantanen et al., 2000; Rosero-Bixby and Dow, 2012; Leong et al., 2015; Xu and Hao, 2017), disability (Giampaoli et al., 1999; Taekema et al., 2010). Yet, very few studies have examined the role of grip strength on subjective health and cognition measures in developing countries. The aim of this study is to assess the association between grip strength, overall and specific dimensions of multidimensional frailty such as functional loss, chronic multimorbidity conditions and quality of life among older adults using the WHO‟s Study on global AGEing and adult health (SAGE) data for the six Low and Middle Income Countries (LMICs) of China, China, Ghana India, Mexico, Russia and South Africa. Materials and Methods We use data from the WHO’s Study on Global Ageing and Adult Health (SAGE). SAGE is a nationally representative household health survey conducted in six countries: China, Ghana, India, Mexico, the Russian Federation and South Africa. This analysis focussed on sample of older adults aged 50 years and above. The analysis was carried out using the nationally representative sample with the total sample of 30155 older adults in age 50+. Details on sampling and the methodology are available in Kowal et al, 2012. SAGE is nationally representative and cohort study conducted in six countries; India, China, Ghana, Mexico, Russia and South Africa during 2007-10. The aim of the SAGE was to fulfil the data gaps to 2 | P a g e

understand the health and wellbeing of the growing aging population in six low and middle- income countries. SAGE measures are comparable with other studies from high-income countries such as the Health and Retirement Study (HRS), the Survey of Health, Ageing and Retirement in Europe (SHARE). SAGE collects data on self-reported as well as biomarkers data on different domains of health, wellbeing and anthropometric indicators. A detailed information about data description given in Kowal et al. (2012). Definition and Variable Construction Grip strength Grip strength is a measure of muscle strength which is a strong predictor of individual health, functionality and mortality. In WHO-SAGE grip strength was assessed in both the hands using a hand dynamometer. In the analysis, we have taken the best of four measurements. Since, grip strength is one of the main outcome variable in this study, we excluded outliers. The main analysis excluded less than 1 and above 99 percentile of grip strength measurements. Multi-morbidity Mult-morbidity is defined as the presence of one or more chronic condition at the time of data collection. We have included eight chronic health conditions, namely: arthritis, stroke, angina pectoris, diabetes mellitus, asthma, hypertension, chronic lung disease and visual acuity. Among these, for arthritis, angina pectoris, asthma, lung disease, SAGE survey provides two types of measures: First, self-reports of the diagnosis of individual diseases and second is the symptom based assessment or direct health examination of abovementioned diseases. The specific question asked in SAGE for self- reports is: “Have you ever been diagnosed with/told that you have disease name? Thus, we have considered an individual as suffering from these diseases if he/she is found positive in the symptom based assessment. For, stroke and diabetes mellitus we have relied on the self-reports of diagnosis and for hypertension and visual acuity, we have used measured outcomes of blood pressure monitor and vision test. Self-Rated Health (SRH) This study used self-rated health as one of the outcome variables. In SAGE, self-rated health was assessed on a five-point scale with the following question: In general, how would you rate your health today? The response categories were: ‘very good’, ‘good’, ‘moderate’, ‘bad’ and 3 | P a g e