Effect of grip strength on mental health

Highlights

• Participants with lower grip strength were at greater risk of developing mental illness.

• Lower grip strength may be a causative factor in the risk of mental illness.

• Stronger association in 65 years or more participants than 64 years or less for cognitive function is showed.

Abstract

Background

This study is to longitudinally investigate the association between grip strength and mental health disorders in middle aged and aged population from the Korean Longitudinal Study of Aging.

Methods

Data from the Korean Longitudinal Study of Aging (KLoSA) from 2006 to 2016 was assessed using longitudinal data analysis and out of the 9279 research subjects gathered 1549 (16.7%) participants were reported as Q1 group and 2074 (22.4%) participants were reported as Q5 group. To analyze the association between grip strength and mental health disorders, generalized estimating equation (GEE) model was used.

Results

The association between grip strength and cognitive decline was statistically significant, with the following Odds ratio (OR) predicting decreased cognitive decline: OR = 4.99 (p < .0001) for Q1 group vs. Q5 group. The association between grip strength and MMSE and CESD was also statistically significant, with the following estimate (B) predicting decreased MMSE score: B = −0.12 (p < .0001) for Q1 group vs. Q5 group. In terms of CESD, CESD score was higher for Q1 group (B = 0.34, p < .0001) compared to Q5 group.

Conclusion

This study shows a significant association between grip strength and risk of mental illness in Korean middle aged and aged population. Therefore, grip strength should be given more focus in terms of resistance training programs.

Introduction

In modern society, mental illness is a major concern, because it is one of the leading causes of years lived with disability globally (Whiteford et al., 2015). Furthermore, the World Health Organization (WHO) reported that the total number of people with mental illness exceeded 300 million in 2015 (World Health Organization. Depression and Other Common Mental Disorders: Global Health Estimates. Geneva: WHO, 2017).

Those with mental illness such as depression or dementia may show non‐cognitive features such as decreased physical function (Scarmeas et al., 2005, Vancampfort et al., 2017) and objective physical performance (Dalle Carbonare et al., 2009), suggesting that a decline in physical function might predict the risk of having mental illness (Yanagita et al., 2006). Previous studies revealed that those with a decline in physical function are at greater risk of falls, health care use, level of dependency, admissions to residential care, mortality (Freedman et al., 2002), cardiovascular disease and other complications (Brown et al., 2005, Landi et al., 2012, Studenski et al., 2011, Yanagita et al., 2006).

The nature of the association between physical function and mental illness is still uncertain, but shared age‐related muscular weakness has been suggested (Christensen et al., 2001, Mehta et al., 2002). Low grip strength is a well‐recognized feature of decreased age‐related physical function (Veronese et al., 2017). Moreover, grip strength, one of the promising candidates for the brief evaluation of physical function, is used to predict future activities of daily life (Rantanen et al., 1999). Several studies have shown that grip strength is a valid and a non-invasive measure of physical performance that has been widely used in research and clinical settings (Giampaoli et al., 1999, Onder et al., 2005).

Some studies have shown the protective influence of grip strength on mental illness (Fukumori et al., 2015, Hamer et al., 2015). However, because these findings were derived from somewhat small sample sizes that were collected over twenty year ago, there is a need to demonstrate the replicability of these findings using larger population samples. In addition, although several studies have found that low grip strength is associated with risk of mental illness in Western populations, few studies have been carried out in Asian populations (Alfaro-Acha et al., 2006, Buchman et al., 2007). Finally, while previous studies have suggested a cross sectional association between grip strength and mental illness (Gale et al., 2011, van Milligen et al., 2011), the relationship between low grip strength and increased risk of mental illness using longitudinal database has not been evaluated.

Therefore, taking these points into account, we aimed to explore grip strength and mental health disorders in middle aged and aged population from the Korean Longitudinal Study of Aging.