Lifestyle-related factors associated with mobility decline in middle-aged adults: A 7-year longitudinal observation of health checkup database.

BACKGROUND: Mobility decline increases risks of falls, long-term care, and mortality, yet it may start in midlife. We examined lifestyle-related factors for the incident mobility decline in middle-aged adults. METHODS: We conducted a 7-year cohort study using a health checkup database from an urban area of Japan (2016-2023). Participants without baseline mobility limitation were included; those without 2023 follow-up or with missing data were excluded. Mobility was assessed at baseline and follow-up using locomotive syndrome (LS) risk tests, including two-step and stand-up tests and the Geriatric Locomotive Function Scale-25. Baseline lifestyle habits and lifestyle-related conditions were collected. The main outcome was incident LS at follow-up. Multivariable logistic regression assessed associations between baseline factors and LS development. RESULTS: Among 10,445 participants (median age 47 years [interquartile range 42-53]; 3949 [38%] female), 1205 (12%) developed LS over 7 years, mainly due to deterioration in the stand-up test (681, 6%) and Geriatric Locomotive Function Scale-25 (566, 6%). In analyses stratified jointly by age group and sex, high waist circumference was associated with incident LS in women across all age groups and in men aged 40-49 and 50-59 years. Diabetes was associated with incident LS in men aged 40-49 and 50-59 years. However, interaction analyses did not provide statistical evidence that these associations differed across age-sex subgroups. CONCLUSIONS: High waist circumference and diabetes in midlife were associated with incident LS over 7 years, although residual confounding factors and potential informative censoring due to loss to follow-up may have influenced these associations.