Fig. 3

Association between sleep duration and BMD. A overall population; B individuals aged < 60 years; C individuals aged ≥ 60 years; D men; E non-postmenopausal women; F postmenopausal women. Model 1: unadjusted model; Model 2: age, sex/menopause status, race, and BMI were adjusted; Model 3: age, sex/menopause status, race, income level, BMI, smoking status, alcohol drinking status, physical activity level, fractures history, glucocorticoid use, family history of osteoporosis, CCI, calcium intake, vitamin D intake, and serum 25-hydroxyvitamin D were adjusted. Group 1: SD = 7–8 h/day; Group 2: SD = 6 h/day; Group3: SD < 6 h/day; Group 4: SD > 8 h/day. BMD, bone mineral density; BMI, body mass index; CCI, Charlson Comorbidity Index; FN, femoral neck; SD, sleep duration; TF, total femur; TS, total spine. * p < 0.05; ** p < 0.01