Sarcopenia is Associated With Decreased Brain Volume in the General Population: A Longitudinal Cohort Study

Abstract

Background: Substantial evidence supports an association between physical activity and cognitive function. However, the role of muscle mass and function in brain structural changes is not well known. This study investigated whether sarcopenia, defined as low muscle mass and strength, affects brain atrophy in the general middle-to-later aged population. Methods: A total of 1284 participants with sarcopenic measurements and baseline and 4-year follow-up brain magnetic resonance images were recruited from the Korean Genome and Epidemiology Study. Muscle mass was represented as appendicular skeletal muscle mass divided by the body mass index. Muscle function was measured by handgrip strength. The low mass and strength groups were defined as being in the lowest quintile of each variable for one’s sex. Sarcopenia was defined as being in the lowest quintile for both muscle mass and strength. Findings: Of the 1284 subjects, 12·6%, 10·8%, and 5·4% were classified as the low mass, low strength, and sarcopenia groups, respectively. All three groups presented greater loss in gray matter (GM) volume than the control group. The adjusted mean changes of GM volume during 4-year follow-up period were -9·6 mL in the control group, whereas -11·6 mL in the other three groups (P < 0·001). For lobar brain volumes, the low mass group presented greater atrophy in frontal and occipital GM. The significantly faster atrophy in parietal GM was observed in the sarcopenia group compared with the control group, mostly driven by atrophy in the left inferior parietal lobule. In a joint regression model, low muscle mass, but not muscle strength, was an independent factor associated with rapid GM atrophy. Interpretation: Sarcopenia is associated with rapid declines in GM volume, especially parietal GM volume, in the general population. Maintaining good levels of muscle mass could be important for brain health in later adulthood. Funding Statement: This research was supported by funds (2009-E71002-00, 2010-E71001-00, 2011-E71004-00, 2012-E71005-00, 2013-E71005-00, 2014-E71003-00, 2015-P71001-00, 2016-E71003-00, 2017-E71001-00, 2018-E7101-00) from the Korean Centers for Disease Control and Prevention, the Bio & Medical Technology Development Program of the National Research Foundation (NRF) funded by the Korean government (MSIT) (NRF-2019M3E5D3073102,2019R1H1A2039682, 2020R1F1A1074265), a Korea University Grant (K1824431), Ansan-Si hidden champion fostering and supporting project funded by Ansan city, and computational resources provided by the University of Iowa, Iowa City, Iowa. . Declaration of Interests: No potential conflicts of interest relevant to this article are reported. Ethics Approval Statement: Each participant signed an informed consent form. This study was performed according to the principles of the Declaration of Helsinki of the World Medical Association and was approved by the Institutional Review Board of Korea University Ansan Hospital.