Aims: A role for iron in the risk of ischaemic heart disease has been supported by in vitro and in vivo studies. We investigated whether dietary haem iron intake is associated with coronary heart disease (CHD) risk in a large population-based cohort of middle-aged women.
Methods and results: We used data of 16 136 women aged 49-70 years at recruitment between 1993 and 1997. Follow-up was complete until 1 January 2000 and 252 newly diagnosed CHD cases were documented. Cox proportional hazards analysis was used to estimate hazard ratios of CHD for quartiles of haem iron intake, adjusted for cardiovascular and nutritional risk factors. We stratified by the presence of additional cardiovascular risk factors, menstrual periods, and antioxidant intake to investigate the possibility of effect modification. High dietary haem iron intake was associated with a 65% increase in CHD risk [hazard ratio (HR)=1.65; 95% confidence interval (CI): 1.07-2.53], after adjustment for cardiovascular and nutritional risk factors. This risk was not modified by additional risk factors, menstruation, or antioxidant intake.
Conclusion: The results indicate that middle-aged women with a relatively high haem iron intake have an increased risk of CHD.