Association between Bone Mineral Density and Sleep Duration in the Korean Elderly Population

BACKGROUND An association between sleep duration and a wide spectrum of diseases has been reported, but little is known about its relationship with bone mineral density (BMD). Previously conducted studies in Korea and abroad have reported results that are controversial. The present study sought to assess whether sleep duration can be considered an independent risk factor of osteoporosis. METHODS We included participants over the age of 60 years with data on self-reported habitual sleep duration and BMD measured with dual X-ray absorptiometry. Comprehensive data on the study sample was obtained from the Korea National Health and Nutritional Survey performed from 2008 to 2010. Sex-stratified multiple regression analyses were conducted with adjustments for possible confounding factors. RESULTS There was a significant inverse dose-dependent association between sleep duration and BMD measured at total hip, femur neck, and lumbar spine for women and total hip and femur neck for men. Sex-stratified regression analyses adjusted for age and body mass index revealed that sleep duration had a negative correlation with BMD at total hip and femoral neck for both women (β = -0.0048; P = 0.0172 for total hip, β = -0.0037; P = 0.0303 for femur neck) and men (β = -0.0057; P = 0.0218 for total hip, β = -0.0057; P = 0.0143 for femur neck). For women, the significance remained after further adjustment of confounding variables. CONCLUSION Prolonged sleep duration appears to have a significant association with lower total hip and femur neck BMD in elderly women but not in elderly men.