The mediating role of BMI in the relationship between OSAHS and bone metabolism in male patients with T2DM.

OBJECTIVE

This study aims to investigate the potential association between obstructive sleep apnea hypopnea syndrome (OSAHS) and bone metabolism in male patients with type 2 diabetes mellitus (T2DM), and to further analyze the mediating role of body mass index (BMI) in this relationship. By elucidating the interaction mechanisms between OSAHS and bone metabolism, this study seeks to provide a scientific basis for early screening and intervention of bone metabolism abnormalities in male T2DM patients, thereby improving their clinical outcomes.

METHODS

This study analyzed 418 male T2DM inpatients from the Department of Endocrine and Metabolic Diseases at the First People's Hospital of Changzhou between May 2020 and May 2024. Patients were categorized into the pure T2DM group and the T2DM with OSAHS group based on their apnea-hypopnea index (AHI). Linear correlation and multiple linear regression analyses were employed to evaluate the relationships among OSAHS, BMI, and bone metabolism indicators. Finally, mediation analysis was conducted to assess the mediating effect of BMI.

RESULTS

Among OSAHS indicators, nocturnal lowest oxygen saturation (LSaO2) correlated with total N-terminal propeptide of type I collagen (TP1NP). A 1-SD increase in LSaO2 was associated with a 2.532 ng/ml increase in TP1NP (95% CI: 0.232 ~ 4.832, P < 0.05). While BMI was positively correlated with bone mineral density (BMD), no correlation was found between BMI and bone turnover markers (BTMs). The oxygen desaturation index (ODI) and proportion of cumulative sleep time with oxygen saturation below 90% in total sleep time (T90) was initially correlated with BMD at the different sites, but the association was nullified after adjusting for BMI. Mediation analysis showed that BMI fully mediated the relationship between ODI T90 and BMD, with no influence on the association between LSaO2 and BTMs.

CONCLUSION

OSAHS-induced hypoxia may inhibit osteoblastic activity, which warrants further investigation. Additionally, while BMI fully mediates the relationship between ODI and BMD, further studies are needed to exclude the potential influence of BMI on BMD measurements.