Higher physical activity levels are associated with reduced risk of limb fracture but not vertebral fracture in middle-aged and older Japanese adults: a 12-year cohort study.

BACKGROUND

Physical activity (PA) levels are inversely associated with hip fracture risk, but whether this is the case for other types of fractures, especially vertebral fractures, is unclear. The present study aimed to examine whether PA levels are associated with osteoporotic fracture risk in community-dwelling people.

METHODS

This cohort study analyzed 13,558 Japanese people aged 40-74 years (6,756 women and 6,802 men). Information on demographic characteristics, body size, lifestyle, and disease history was obtained by a self-administered questionnaire conducted in the 2011-2013 baseline survey. Levels of total PA excluding sleep, sitting, and other sedentary activities (TPA) were estimated by the metabolic equivalents score (MET-h/d). Incident limb fractures (distal radius, humeral neck, and hip) and vertebral fractures were identified in medical records. A Cox proportional hazards model was used to calculate hazard ratios (HRs).

RESULTS

During a mean follow-up period of 12.1 years, 966 fractures occurred (725 in women and 241 in men). Higher TPA levels were associated with a lower hazard of limb fracture (P for trend=0.0244), with the highest quintile having a lower HR (HR=0.67; 95%CI, 0.49-0.90) than the reference (lowest quintile). Higher LTPA levels were associated with a lower hazard of limb fracture (P for trend=0.0077), with the highest level having a lower HR (HR=0.73; 95%CI, 0.58-0.92) than the reference. No PA measures were associated with vertebral fracture.

CONCLUSION

Higher levels of PA of any type are associated with a low risk of limb fracture, but not clinical vertebral fracture, in Japanese adults.