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: ß = 0.023; Ptrend  = 0.004, women: ß = 0.011; Ptrend  = 0.012). Further adjustment for high-sensitivity C-reactive protein did not materially alter the results (men: ß = 0.023; Ptrend  = 0.005, women: ß = 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: ß = 0.208; Ptrend  = 0.085, women: ß = 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.

Inverse association between coffee drinking and the risk of hepatocellular carcinoma: a case-control study in Japan.

Coffee use has consistently been associated with lower serum liver enzyme levels and a reduced risk of liver cirrhosis. A limited number of cohort and case-control studies also suggest a decreased risk of hepatocellular carcinoma (HCC) among coffee drinkers, but mostly without consideration of hepatitis virus infection. In the present case-control study, we recruited 209 incident HCC cases and three different controls (1308 community controls, 275 hospital controls, and 381 patients with chronic liver disease [CLD] without HCC), all of whom were aged 40-79 years and residents of Saga Prefecture, Japan. A questionnaire survey elicited information on coffee use during the last 1-2 years and 10 years before, and plasma hepatitis B surface antigen and antibodies to hepatitis C virus were tested for all but community controls. After adjustment for sex, age, heavy alcohol use, smoking status and hepatitis virus markers (except for community controls), coffee use during the last 1-2 years was associated with a decreased risk against any control group. For coffee use 10 years before, comparison between HCC cases and either community controls or CLD patients revealed a decreased risk; adjusted odds ratios for occasional use, 1-2 cups/day and > or =3 cups/day compared with no use were 0.33, 0.27 and 0.22 (P trend < 0.001), respectively, against community controls, and 0.86, 0.62 and 0.53 (P trend = 0.05), respectively, against CLD patients. These results suggest that coffee may protect against the development of HCC, yet further elaborate studies (hopefully, intervention studies) are warranted to corroborate these findings.