Decreased iron stores are associated with cardiovascular disease in patients with type 2 diabetes both cross-sectionally and longitudinally

Background and aims: The possible contribution of iron to cardiovascular complications of type 2 diabetes (T2D) has been scarcely investigated. We aimed to study whether serum ferritin is linked to prevalent/incident cardiovascular disease (CVD) in T2D. Methods: The prevalence of coronary heart disease (CHD), cerebrovascular disease (CEVD) and CVD was evaluated in the SIDIAP study (n = 38,617) and prevalence and 7-year incidence were analysed in the Edinburgh Type 2 Diabetes Study (ET2DS) (n = 821). Logistic and Cox regressions were used to describe associations between serum ferritin and CVD adjusting for confounding variables. Results: Increase of 1 SD unit in log-ferritin was associated with lower CVD prevalence in fully-adjusted models (ET2DS odds ratio (OR) 95% confidence interval (CI): 0.81 (0.68–0.96), p = 0.018; SIDIAP study: 0.91 (0.88–0.94), p < 0.001). In ET2DS, ferritin in the highest (vs. the lowest) quintile was associated with lower incidence of CVD (fully adjusted HR 95% CI: 0.46 (0.26–0.83), p = 0.010). This association persisted after removing subjects with CVD at baseline (n = 536) (HR 95% CI: 0.34 (0.14–0.81), p = 0.016). Conclusions: Low iron status was associated with CVD risk in T2D. This pattern was consistent in populations at different cardiovascular risk. Low iron status seems to be harmful for cardiovascular health in T2D and it may be a target for intervention.