Association between habitual coffee consumption and skeletal muscle mass in middle-aged and older Japanese people

AIMS Coffee consumption has been suggested, in animal studies, to inhibit the progression of sarcopenia, possibly through its anti-inflammatory effects; however, few studies have been carried out in humans. We aimed to examine whether coffee consumption was related to indicators of sarcopenia in a Japanese population, and whether the association was mediated by reduced inflammation. METHODS This study was a cross-sectional design. Participants were community residents (n = 6369) aged 45-74 years. We measured skeletal muscle mass index (SMI; kg/m2 ) by a bioelectrical impedance method, and grip strength with a Smedley-type dynamometer. Habitual coffee consumption was assessed by a self-administered questionnaire. Serum high-sensitivity C-reactive protein was measured as an inflammatory marker. The association between habitual coffee consumption and SMI or grip strength was analyzed with a linear regression model adjusted for covariates. RESULTS A significant positive association was found between coffee consumption and SMI (men: β = 0.023; Ptrend = 0.004, women: β = 0.011; Ptrend = 0.012). Further adjustment for high-sensitivity C-reactive protein did not materially alter the results (men: β = 0.023; Ptrend = 0.005, women: β = 0.009; Ptrend = 0.024). The relationship between coffee consumption and grip strength did not reach statistical significance; however, a positive trend was observed (men: β = 0.208; Ptrend = 0.085, women: β = 0.092; Ptrend = 0.167). CONCLUSIONS We found that coffee consumption was positively associated with SMI independently of inflammation in middle-aged and older Japanese people. Reduced inflammation by coffee does not seem to be an important mediator, and further investigations are required to explore the mechanisms of this association. Geriatr Gerontol Int 2021; 21: 950-958.