Objectively measured sleep parameters and bone health: results from the Human Phenotype Project (HPP) cohort

Using highly precise measurements, we found obstructive sleep apnea (OSA) was linked to poorer bone health at most sites. Higher oxygen saturation, rather than sleep efficiency, was beneficial. Total sleep duration was partially nonlinearly related to bone health. Patients with chronic sleep problems should be screened for low BMD. AIM: Previous studies have shown associations between sleep characteristics and bone health, but findings are inconsistent. This study investigated the relationships between objectively measured sleep characteristics and bone mineral density (BMD) as well as bone mineral content (BMC) using dual-energy X-ray absorptiometry (DXA) measurements at various skeletal sites. METHODS: The analysis included data from 4690 participants aged 40-70 years in the Human Phenotype Project (HPP) cohort. Associations between total sleep time, mean oxygen saturation (%), sleep efficiency, and obstructive sleep apnea (OSA) indices-respiratory disturbance index (RDI), apnea-hypopnea index (AHI), and oxygen desaturation index (ODI)-measured by a sleep apnea monitoring device, and BMD/BMC assessed by DXA imaging of various skeletal components were examined using multivariable linear regression models. All associations were tested for interactions with age. RESULTS: OSA indices (AHI, ODI, RDI) showed linear or non-linear inverse associations with BMD or BMC at most bone sites. The negative associations of AHI and ODI with spine outcomes were non-linear, with stronger effects at higher index ranges. Total sleep time was inversely associated with BMC of the legs, femoral neck, and femoral shaft, with consistent estimates for BMD. U-shaped associations were observed between total sleep time and BMC of both arms and spine L2. Oxygen saturation was positively associated with BMD and BMC of the total body, arms, head, and spine. Sleep efficiency showed no association with any outcomes. Age-stratified analyses revealed stronger estimates in younger participants. CONCLUSIONS: OSA appears to be associated with reduced BMD and BMC, even in individuals without other major health conditions. These findings highlight the need for increased clinical awareness, including BMD screening for OSA patients, and, on the other hand, the detection of sleep problems in patients with osteoporosis or reduced BMD and BMC.