Min Bao1, Jianqian Chao2, Mingxin Sheng1, Ruixue Cai1, Na Zhang1, Hongling Chen1. 1. Key Laboratory of Environmental Medicine Engineering of Ministry of Education, School of Public Health, Southeast University, Nanjing, Jiangsu, China. 2. Key Laboratory of Environmental Medicine Engineering of Ministry of Education, School of Public Health, Southeast University, Nanjing, Jiangsu, China. Electronic address: chaoseu@163.com.
Abstract
BACKGROUND: Evidence regarding the associations between muscle strength in different parts of the body and depression is lacking. This study examined whether poor muscle strength is associated with a higher incidence of depression in a large cohort of middle-aged and older adults. METHODS: In total, 5,228 middle-aged and older adults from the China Health and Retirement Longitudinal Study without depression at baseline were followed for 7 years. Their demographic characteristics, chronic diseases and lifestyle behaviors were assessed. After adjusting for relevant variables, a Cox regression was used to determine the relationship between muscle strength and incident depression. RESULTS: Over 32,544 person-years of follow-up, 1,490 participants developed depression. Low muscle strength at baseline was associated with a higher 7-year incident of depression, even after excluding those who developed depression within 2 years. After adjusting for confounding factors, it was found that a higher baseline relative handgrip strength was a protective factor against depression (HR [95% CI]=0.575 [0.430-0.768] for the lowest quartile vs. the highest quartile; p<0.001). Longer times on the 5TSTS test were a risk factor for depression (HR [95% CI]=1.321 [1.077-1.621] for the lowest quartile vs. the highest quartile; p = 0.007). When the strengths of the upper and lower limbs were considered together, the hazard ratio for depression in people with relatively greater muscle strength was 0.463 (95% CI=0.307-0.699; p<0.001). CONCLUSIONS: Muscle strength could be predictive of depression, and the combined measurement of upper and lower limb muscle strength can improve the predictive ability.
BACKGROUND: Evidence regarding the associations between muscle strength in different parts of the body and depression is lacking. This study examined whether poor muscle strength is associated with a higher incidence of depression in a large cohort of middle-aged and older adults. METHODS: In total, 5,228 middle-aged and older adults from the China Health and Retirement Longitudinal Study without depression at baseline were followed for 7 years. Their demographic characteristics, chronic diseases and lifestyle behaviors were assessed. After adjusting for relevant variables, a Cox regression was used to determine the relationship between muscle strength and incident depression. RESULTS: Over 32,544 person-years of follow-up, 1,490 participants developed depression. Low muscle strength at baseline was associated with a higher 7-year incident of depression, even after excluding those who developed depression within 2 years. After adjusting for confounding factors, it was found that a higher baseline relative handgrip strength was a protective factor against depression (HR [95% CI]=0.575 [0.430-0.768] for the lowest quartile vs. the highest quartile; p<0.001). Longer times on the 5TSTS test were a risk factor for depression (HR [95% CI]=1.321 [1.077-1.621] for the lowest quartile vs. the highest quartile; p = 0.007). When the strengths of the upper and lower limbs were considered together, the hazard ratio for depression in people with relatively greater muscle strength was 0.463 (95% CI=0.307-0.699; p<0.001). CONCLUSIONS: Muscle strength could be predictive of depression, and the combined measurement of upper and lower limb muscle strength can improve the predictive ability.