BMI与腰围对阻塞性睡眠呼吸暂停与2型糖尿病的中介效应

目的  探究BMI和腰围(waist circumference, WC)对阻塞性睡眠呼吸暂停(obstructive sleep apnea, OSA)与2型糖尿病、糖代谢连续测量指标之间的中介效应。方法  纳入分析的1 615名研究对象来自动脉粥样硬化多民族研究(Multi-Ethnic Study of Atherosclerosis, MESA)。OSA评价指标为呼吸暂停低通气指数(apnea-hypopnea index，AHI)，由多导睡眠图测定。糖代谢连续测量指标包括FPG和糖化血红蛋白(glycated hemoglobin，HbA1c)。肥胖指标包括全身肥胖指标BMI和腹型肥胖指标WC。结果  OSA与2型糖尿病显著相关，后者的患病风险随OSA严重程度增加而升高(P < 0.001)。BMI和WC均介导重度OSA与2型糖尿病之间的关联，其中腹型肥胖指标WC的中介效应为1.296(95% CI: 1.182~1.466)，中介效应比例为56.397%；BMI的中介效应为1.291(95% CI: 1.173~1.479)，中介效应比例为55.400%。BMI和WC同样介导重度OSA与FPG、HbA1c之间的关联。结论  OSA与2型糖尿病、FPG和HbA1c的关系，与肥胖程度增加有关。提示OSA患者通过早期的体重干预，特别是控制腹型肥胖对降低糖尿病和心血管并发症的患病率具有重要意义。

Mediating effect of body mass index and waist circumference on the relationship between obstruc-tive sleep apnea and type 2 diabetes

  Objective  To evaluate the mediating effect of BMI and waist circumference (WC)on the relationships between obstructive sleep apnea (OSA) and type 2 diabetes and continuous measures of glucose metabolism.  Methods  A total of 1 615 participants from the Multi-Ethnic Study of Atherosclerosis (MESA) were included in this cross-sectional study. OSA severity was assessed by apnea-hypopnea index (AHI), which was measured by polysomnography. Continuous measures of glucose metabolism were FPG and glycated hemoglobin (HbA1c). And obesity indexes used in this study included general obesity (BMI) and abdominal obesity (WC).  Results  OSA was significantly associated with type 2 diabetes. With increasing the severity of OSA, there was a significant increase in the risk of type 2 diabetes (P < 0.001). Mediation analysis showed that BMI and WC mediated the association between severe OSA and type 2 diabetes, respectively. The indirect effect mediated by WC and BMI were 1.296 (95% CI: 1.182-1.466) and 1.291 (95% CI: 1.173-1.479), and the proportion of mediation were 56.397% and 55.400%, respectively. Similarly, BMI and WC mediated the associations between OSA and FPG and HbA1c.  Conclusions  These findings show that the associations between OSA and type 2 diabetes, FPG and HbA1c are mediated by obesity indexes to a large proportion. It is suggested that weight control, especially reducing abdominal obesity, may have an important role for OSA patients in decreasing the risk of type 2 diabetes and related cardiovascular complications.