Association Between Magnesium : Iron Intake Ratio And Diabetes In Chinese Adults In Jiangsu Province

Z.-M. Shi*†, X.-S. Hu*, B.-J. Yuan*, R. Gibson†, Y. Dai* and M. Garg†‡  *Jiangsu Provincial Centre for Disease Control and Prevention, Nanjing, China,   †Research Centre for Gender, Health and Ageing, Hunter Medical Research Institute and   ‡Nutraceuticals Research Group, School of Biomedical Sciences, University of Newcastle, NSW, Australia

Correspondence to: Zu-Min Shi MD PhD, Department of Nutrition and Food Hygiene, Jiangsu Provincial Center for Disease Control and Prevention, 172 Jiangsu Road, Nanjing 210009, China. E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it

Copyright Journal compilation © 2008 Diabetes UK.  Diabet. Med. 25, 1164–1170 (2008)

ABSTRACT

Background  The intake of iron is positively related to the risk of diabetes, whilst magnesium intake is inversely related. However, it is unknown whether there is an interaction between dietary magnesium and iron expressed as a ratio and diabetes.

Methods  This is a cross-sectional household survey carried out in 2002 in Jiangsu Province, China. A total of 2849 men and women aged ≥ 20 years participated (participation rate 89.0%). Iron and magnesium intake was assessed by 3-day weighed food records. Fasting plasma glucose, serum ferritin and haemoglobin were measured.

Results  The mean intake of iron and magnesium was 25 mg/day and 332 mg/day, respectively. The prevalence of diabetes was 3.0% in men and 2.6% in women. Magnesium intake was negatively associated with diabetes when adjusted for age and sex, but not in a fully adjusted model. A strong inverse association between magnesium : iron intake ratio and diabetes was observed. In the fully adjusted model, the odds ratios of diabetes across quartiles of magnesium : iron intake ratio were: 1.0, 0.63 [95% confidence interval 0.32–1.25], 0.36 (0.16–0.81) and 0.48 (0.20–1.14) (P for trend 0.038). There was an interaction between central obesity and magnesium : iron ratio.

Conclusion:   Magnesium : iron intake ratio is an independent risk marker for diabetes in Chinese adults. As this is a cross-sectional study, we cannot establish any causal relationship.

Abstract

Objective:  Inflammation and iron deficiency are two important causes of anemia. Magnesium intake is inversely associated with inflammation. However, little is known as to whether magnesium intake is related to anemia. We assessed the joint association of magnesium and iron intake with anemia among Chinese adults.

Methods  A cross-sectional household survey of 2849 men and women 20 y of age or older was conducted in 2002. Nutrient intakes were assessed by 3-d weighed food records. Serum ferritin and hemoglobin concentrations were measured.

Results  The prevalence of anemia was 18.3% in men and 31.5% in women. Magnesium and iron intakes were positively associated with hemoglobin levels and inversely related to the prevalence of anemia. The risks of anemia were reduced by 26% (P for trend = 0.03) and 52% (P < 0.01), respectively, for iron and magnesium intake comparing the fourth quartile with the first with adjustment for potential confounders. The lowest risk of anemia was observed among participants with the highest intakes of magnesium and iron (odds ratio 0.46, 95% confidence interval 0.31–0.68). The inverse association of iron intake and anemia but not the association of magnesium intake and anemia was modified by serum ferritin levels. The observed relations were not appreciably modified by gender.

Conclusion:  This study suggests that magnesium is a potent predictor of anemia in Chinese adults.