Sleep apnea and risk of osteoporosis – A nationwide population-based study

Rationale The relationship between sleep apnea (SA) and osteoporosis remains controversial. A small Turkish case-control study found decreased bone density in male with obstructive SA, whereas a French study showed higher bone density in elders with obstructive SA. We therefore conducted a study using Taiwan National Health Insurance (NHI) database. Methods From a database of 1 million subjects randomly sampled from individuals enrolled in the NHI system in 2005, we identified adult patients with a diagnosis of SA after polysomnography. We excluded those having osteoporosis prior to SA. Each SA patient was matched to 30 randomly-selected, age- and gender-matched control subjects without any diagnosis of SA. The control subjects were assigned with the same index dates. We used Chi-square test and survival analysis to compare the incidences and cumulative incidences of osteoporosis in both groups and Kaplan-Meier method and log-rank test for cumulative incidences analysis. Results We identified 1764 SA patients and 52920 control subjects. No significant difference was noted in the incidence and the cumulative incidence of osteoporosis between two cohorts (p = 0.4190 and 0.8005, respectively). In multivariable Cox regression analysis, SA was not a significant risk factor or protective factor for the development of osteoporosis after adjusting for age, job and comorbidities (hazard ratio = 1.02 [95% confidence incidence: 0.67 – 1.54], p = 0.9438). Conclusions Our study revealed no significant difference in osteoporosis incidence between SA patients and control subjects, even in subgroup analyses. Further detailed analysis is needed to clarify the association between SA and osteoporosis.