Diabetes as a Potential Contributor to Dynapenia in Community‐Dwelling Older Adults in Japan: Sex‐ and Age‐Specific Cross‐Sectional Findings From the Integrated Research Initiative for Living Well With Dementia Cohort Study

AIM: Dynapenia-loss of muscle strength despite preserved muscle mass-is a clinical concern linked to functional decline in older adults. Diabetes may contribute to dynapenia; however, few studies have examined whether this association varies by sex and age. Clarifying these differences may help inform targeted prevention strategies. This study investigated the association between diabetes and dynapenia in community-dwelling older adults in Japan, focusing on sex- and age-specific differences. METHODS: We conducted a cross-sectional analysis using pooled data from four geriatric cohorts in Japan. Participants were classified into three groups: (1) established diabetes (treatment or HbA1c ≥ 6.5%), (2) prediabetes (HbA1c 5.7%-6.4%, no treatment), and (3) non-diabetes (HbA1c < 5.7%, no treatment). Dynapenia was defined per Asian Working Group for Sarcopenia 2019 cutoffs as low grip strength with preserved muscle mass. Sex-stratified logistic regression examined the association between diabetes status and dynapenia, adjusting for age, body fat, comorbidities, lifestyle factors, and cohort. Analyses were also stratified by age group (65-74 and ≥ 75 years). RESULTS: Among 3085 participants (34.8% men; median age: 70 years), the prevalence of dynapenia was 13.0% in both sexes. In women, dynapenia prevalence increased with glycemic status; adjusted ORs were 1.32 (95% CI: 0.97-1.78) for prediabetes and 1.86 (1.27-2.71) for established diabetes. Stratified analyses showed significant associations in men aged 65-74 and women aged ≥ 75. CONCLUSIONS: Diabetes was associated with dynapenia, with distinct patterns by sex and age. Targeted strategies may be needed for younger-old men and older-old women with diabetes.