Comment on: Changes in Leisure Activity, All-Cause Mortality, and Functional Disability in Older Japanese Adults: The JAGES Cohort Study

Abstract

We read with great interest the article by Masuko et al. [1] on any leisure activity in older Japanese adults. This article discusses the consequences of starting and continuing any leisure activity regarding all-cause mortality and functional disability in a prospectively designed study (about 6 years follow-up). The findings of this study reveal how behavior management in terms of leisure activities effectively prevents disability increases and all-cause mortality and contain very striking results. This effectively designed and presented research, with such a large sample (n = 38,125) and a long follow-up period on the stated hypothesis, sheds light on many future studies in the literature in this field.

Besides its well-designed presentation, there are a few points we would like to touch on in interpreting the findings of this study. We especially want to draw attention to the group that started leisure activities in 2010 but did not continue doing them in 2013. The fact that the patients in this group stopped doing leisure activities due to additional physical and/or cognitive disability that developed between 2010 and 2013 may be necessary as an additional confounder in the interpretation of the study results. While investigating the causes in this population, the authors evaluated the cessation of leisure activities due to newly diagnosed cancer, newly developed heart diseases and stroke, diabetes, and respiratory diseases between 2010 and 2013. However, in addition to these diseases, we believe that the progressive decrease in cognitive functions and major depression in this patient group are also decisive in not being able to continue leisure activities. When the study findings regarding these conditions are considered, it is noted that the evaluation of depressive symptoms and cognitive complaints was only conducted at the beginning of the study in 2010. We think that the assessment of patients with depressive symptoms and/or mental complaints again in 2013 will be guided in terms of paying attention to the reasons for this behavior in the group that started leisure activities in 2010 and did not continue the activities in 2013. This could be considered an important confounding factor in interpreting this study's results. In the regression models, the authors say that they included five major comorbidities' changes (cardiovascular disorders, hypertension, diabetes, stroke, respiratory diseases, and cancer) between 2010 and 2013 but did not include other comorbidities such as dementia and depression. As mentioned and explained above, this point can be accepted as a limitation of this study. We believe adding these factors to the regression models can strengthen the findings of this study, If possible.

In particular, the relationship between major depression and physical activity level appears to be bilateral; we can say there is a vicious cycle between them. Depressed individuals are generally seen as more passive and sedentary in terms of physical activity [2]. At the same time, low physical activity levels are seen to increase the risk of depression [3]. It has been shown in previous studies that individuals with major depression engage in low levels of physical activity [4, 5].

When the literature is examined, in one study, older individuals were evaluated in terms of dementia severity, gait characteristics, physical functions, and daily physical activities in a geriatric dementia clinic. According to the severity of dementia, individuals in the group without dementia or with suspected dementia showed better physical functions compared to individuals with mild and moderate/severe dementia [6]. Individuals without dementia or with suspected dementia had higher short physical performance battery results compared to individuals with mild and moderate/severe dementia [6]. This group also had faster walking speed, shorter step time, did more physical activity, and stood longer than the other groups [6]. However, these differences were seen to be more pronounced in the moderate/severe dementia group, especially compared to the mild dementia group [6]. It is known that deterioration in physical functions, especially in gait, begins before cognitive function deterioration in dementia [7, 8]. For example, in the study by Hausdorff et al. decreases in both the quantity and quality of walking were observed in patients with mild cognitive impairment (MCI) [9].

The contribution of this study to the literature cannot be ignored, especially in terms of the results of leisure activity, regardless of its subtype, in terms of the reduction in disability and all-cause mortality. Therefore, we congratulate the authors for this well-planned and presented study. It is clearly seen that the decrease in mortality, even in the case of the late start of leisure activity, and the increase in disability seen in the discontinuation of leisure activity despite an early start are very valuable results when the confounding factors we mentioned are excluded. This study will inspire many more studies in the literature in the future.

M.Y.K. and M.C.K. wrote the letter, and all co-authors have read and approved the final version of the manuscript.

The authors declare no conflicts of interest.

This publication is linked to a related article by Masuko et al. To view this article, visit https://doi.org/10.1111/jgs.19453.