膳食铁摄入量对糖尿病患者全因和心血管疾病死亡率的影响

Effect of dietary iron intake on all-cause and cardiovascular mortality in patients with diabetes mellitus

[目的]旨在揭示膳食铁摄入量对糖尿病患者全因和心血管疾病死亡率的影响。[方法]纳入美国健康和营养问卷调查(NHANES)数据库中的5 970例糖尿病患者,从问卷调查和体格检查中获取基线数据,根据国家死亡指数确认生存状态以及死亡原因(截至2015年12月31日)。应用Cox比例风险回归模型估计铁摄入量与全因死亡率以及心血管疾病死亡率的风险比(HR)和95%可信区间(CI)。应用限制性立方样条模型探索是否存在非线性相关性。[结果]纳入研究的受试者平均年龄61.3岁,其中51.3%为男性,他们的平均膳食铁摄入量为每天14.11 mg。在平均6.3年的随访中,总共发生了1 497例死亡。将平均每天膳食铁摄入量<8.34 mg的受试者设为对照组,与对照组相比,膳食铁摄入量在11.11~14.36 mg的糖尿病患者的全因死亡率最低[HR 0.83(0.70~0.99),P<0.05]。限制性立方样条回归发现膳食铁摄入量与全因死亡率呈非线性相关。然而未见膳食铁摄入量与心血管疾病死亡率存在明显的相关关系。[结论]糖尿病患者的膳食铁摄入量与全因死亡率呈“L”型相关,适量的增加铁摄入量会减少全因死亡率。

Aim To investigate the effect of dietary iron intake on all-cause and cardiovascular mortality in diabetic patients.Methods A total of 5970 diabetic patients who participated in the national health and nutrition examination survey(NHANES)database of America were included.Baseline data were obtained from the questionnaire and physical examination,and the survival status and cause of death were confirmed according to the national mortality index(until December 31,2015).Cox proportional survival analysis was used to estimate the hazard ratio(HR)and 95%confidence interval(CI)for iron intake and all-cause and cardiovascular mortality.Restricted cubic spline analysis was used to explore the existence of nonlinear relationship.Results The mean age of the enrolled subjects was 61.3 years old,51.3%of whom were male,and their mean dietary iron intake was 14.11 mg per day.During a mean follow-up of 6.3 years,a total of 1497 deaths occurred.Daily dietary iron intake<8.34 mg was set as control group.Compared with control group,the risk of all-cause mortality was the lowest in diabetic patients with dietary iron intake between 11.11 and 14.36 mg(HR 0.83(0.70~0.99),P<0.05).Restricted cubic spline regression showed that dietary iron intake was nonlinearly associated with all-cause mortality.However,there was no significant association between dietary iron intake and cardiovascular mortality.Conclusion Dietary iron intake is“L-shaped”associated with the all-cause mortality in diabetic patients,and an appropriate increase of iron intake may decrease the all-cause mortality.