engleski

Bone metabolism and trabecular bone structure in patients with obstructive sleep apnea

Introduction: Obstructive sleep apnea (OSA) is a condition associated with numerous metabolic, cardiovascular and endocrine comorbidities. It is characterized by intermittent hypoxemia and sleep fragmentation that directly affect metabolic processes in the body and might have a negative impact on bone mass and trabecular microarchitecture. The purpose of this study was to determine the differences in bone turnover markers, bone mineral density (BMD) and trabecular bone score (TBS) in patients with newly diagnosed OSA compared to healthy individuals. Materials and methods: A total of 28 male patients with average age of 53.2 years, diagnosed with OSA (apnea-hypopnea index (AHI) 40.5±18.1 events/h), underwent a full- night polysomnography and blood sampling for bone turnover markers. Lumbar spine (L1-L4) BMD and TBS, femoral neck and total hip BMD were measured using dual energy X-ray absorptiometry. All findings were compared to 21 healthy controls matched in age and body mass index (BMI). Results: Statistical analysis showed significantly lower lumbar spine (L1-L4) TBS values in OSA group compared with control group (1.24±0.17 vs. 1.42±0.13, P=0.001), while lumbar spine (L1-L4), femoral neck and total hip area BMD and T-score showed no significant difference. Patients with OSA had statistically higher values of serum total alkaline phosphatase (ALP-T), bone- specific alkaline phosphatase (ALP-B), osteocalcin (OC), amino pro-peptide of type 1 collagen (P1NP) and beta- CrossLaps (beta-CTx) compared with control group. Significant positive correlations were found between AHI and ALP-T (r=0.386, P=0.042), as well as ALP-B (r=0.563, P=0.001) and P1NP (r=0.474, P=0.011), while significant negative correlation was found between AHI and lumbar spine (L1-L4) TBS values (r=-0.493, P=0.007). Conclusions: Our study showed that lumbar spine TBS is significantly lower in OSA patient group compared to controls, while total bone turnover metabolism is heightened. Acknowledgements: Study was funded by Croatian Science Foundation project #5935.

obstructive sleep apnea ; trabecular bone structure ; bone metabolism

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