Association Between Obstructive Sleep Apnea and Osteoporosis: A Systematic Review and Meta-Analysis.

Context: Hypoxia reduces osteoblast growth resulting in bone thinning and osteoporosis. Although obstructive sleep apnea (OSA) with recurrent hypoxia might be a contributing factor for osteoporosis development, whether OSA is a risk or protective factor for osteoporosis has not been demonstrated. Objectives: This systematic review and meta-analysis evaluated the association between OSA and osteoporosis using published observational studies. Data Sources: PubMed/MEDLINE and EMBASE databases Study Selection: We completed a systematic review and meta-analysis of published observational studies that evaluated incidence or prevalence of osteoporosis or bone mineral density in obstructive sleep apnea compared with controls. Severity of OSA was char- acterized using the apnea-hypopnea index (AHI). Data Extraction: Primary outcomes were incidence, prevalence, or odds ratio of having osteoporosis, defined as bone mineral density T-score < -2.5 SD. Results: Of 353 articles, 344 articles were excluded, 9 underwent full-length review and data were extracted from 7 studies consisting of 113,558 patients. Finally, 3 extracted studies were included in the meta-analysis of osteoporosis. Among cohort studies, the pooled odds ratio of osteoporosis in patients with OSA was 1.92 (95% confidence interval (CI): 1.24 - 2.97) compared with controls. Among cross-sectional studies, odds of osteoporosis was higher in controls compared with patients with OSA (OR = 0.60, 95% CI: 0.42 - 0.87). In subgroup analysis by gender and study design, in both sexes, only cohort studies had higher odds of osteoporosis compared with controls. Conclusions: There was significant association between OSA and osteoporosis in studies with cohort design. Further prospec- tive studies with large numbers of patients adjusted for the eects of age, sex, or BMI are required to comprehensively determine whether OSA is a risk factor for osteoporosis.