Dietary Iron Intake Predicts All-Cause Mortality in Patients with Diabetes

Abstract

Background: The evidence regarding dietary iron intake and mortality in diabetes is scarce. This study examined the association of dietary iron intake with all-cause and cause-specific mortality among diabetic population. Methods: This study enrolled 5,970 participants with diabetes from the National Health and Nutrition Examination Survey (NHANES) 1999-2014. Baseline data were acquired from questionnaires and examinations. Death status were ascertained from National Death Index records until 31 December 2015. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% CIs for mortality from all causes, cardiovascular disease (CVD) and cancer. Results: The mean iron intake was 14.11 mg daily in the cohort with an average age of 61.3 and 3059 (51.3%) male adults. During 41,425 person-years of follow-up, 1,497 deaths occurred. After multivariable adjustment, iron intake ranging between 11.11 and 14.37 mg was associated with the lowest risk of all-cause mortality (HR 0.83 [0.70, 0.99], p<0.05) compared with the reference group (<8.34 mg). The dose-response curves revealed a L shape in men and a J shape in women in regards of association between iron intake and all-cause mortality. Conclusions: Dietary iron intake was nonlinearly associated with all-cause mortality in diabetic individuals. For men, sufficient iron intake increased all-cause mortality, while it may be protective for women. Funding: None to declare. Declaration of Interest: None to declare. Ethical Approval: The protocol was approved by Ethics Review Board of Hangzhou First People’s Hospital.