Associations between sleep duration and bone mineral density (BMD)^a.

a Values in the table are β coefficients and 95% confidence intervals from regression models, with 8h as the reference category.
b Adjusted for age (years), educational level, smoking status (never smoke, past smoker and current smoker), drinking status (not current drinker, current moderate drinker and current heavy drinker), body mass index (Kg/m2), physical activity score, presence of hypertension (y/n), diabetes (y/n), arthritis (y/n), plasma 25-hydroxyvitamin D concentration (ng/mL), snoring frequency (every/most night, a few nights a week, and occasionally/rare) and osteoporosis medication use (y/n), CES-D score among men, and menopause status(y/n; women alone).
* p<0.05 relative to the reference category (8 h/d).
Associations between sleep duration and bone mineral density (BMD)a.