Association between serum ferritin, hemoglobin, iron intake, and diabetes in adults in Jiangsu, China.

OBJECTIVE To investigate the association between iron status, iron intake, and diabetes among Chinese adults. RESEARCH DESIGN AND METHODS This cross-sectional household survey was carried out in 2002 in Jiangsu Province, China. The sample contained 2,849 men and women aged > or =20 years with a response rate of 89.0%. Iron intake was assessed by food weighing plus consecutive individual 3-day food records. Fasting plasma glucose (FPG), serum ferritin, and hemoglobin were measured. RESULTS The prevalence of anemia was 18.3% in men and 31.5% in women. Mean hemoglobin and serum ferritin increased across groups with increasing FPG. The prevalence of anemia among women was 15.0% in individuals with FPG >7.0 mmol/l compared with 32.6% in individuals with FPG <5.6 mmol/l. There was a similar, however not significant, trend among men. In women, after adjusting for known risk factors, the odds ratio (OR) of diabetes was 2.15 (95% CI 1.03-4.51) for subjects in the upper quartile of hemoglobin compared with the rest, and the corresponding OR for the upper quartile of serum ferritin was 3.79 (1.72-8.36). Iron intake was positively associated with diabetes in women; fourth quartile intake of iron yielded an OR of 5.53 (1.47-20.44) compared with the first quartile in the multivariate analyses. In men, similar trends were suggested, although they were not statistically significant. CONCLUSIONS Iron status and iron intake was independently associated with risk of diabetes in Chinese women but not in men.