Applied nutritional investigation
Joint association of magnesium and iron intake with anemia among
Chinese adults
Zumin Shi, M.D., Ph.D.
a,b,
*, Xiaoshu Hu, M.D.
a
, Ka He, M.D., Sc.D.
c
, Baojun Yuan, M.D.
a
,
and Manohar Garg, Ph.D., M.N.D.
b,d
a
Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, China
b
Research Center for Gender, Health and Ageing, Hunter Medical Research Institute, The University of Newcastle, Australia
c
Departments of Nutrition and Epidemiology, Schools of Public Health and Medicine, University of
North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
d
Nutraceuticals Research Group, School of Biomedical Sciences, The University of Newcastle, Australia
Manuscript received January 8, 2008; accepted May 9, 2008.
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 ϭ 0.03) and 52% (P Ͻ 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. © 2008 Elsevier Inc. All rights reserved.
Keywords: Anemia; Magnesium; Iron; Epidemiology; Chinese
Introduction
Anemia is a worldwide health problem, especially in
developing countries [1]. According to a Chinese national
survey conducted in 2002, the prevalence of anemia was
15.2% in China [2]. Among various risk factors, iron defi-
ciency and inflammation are recognized as two important
causes of anemia [1]. Low iron content in food and low
bioavailability of iron intake from plant-based food are the
main nutritional causes of iron deficiency. Iron-fortified
wheat flour and soy sauce have been recommended for the
prevention of iron deficiency anemia (IDA) [1,3].
Studies have suggested that magnesium intake is in-
versely associated with risk of diabetes and metabolic syn-
drome [4–6] and with markers of systemic inflammation
[7–9]. Increased magnesium intake may improve dyslipide-
mia, oxidative stress, and insulin sensitivity in type 2 dia-
betes [10]. Magnesium supplementation reduces the risk of
This work was funded by the Jiangsu Provincial Health Bureau. Dr. Shi
is supported by a fellowship from the Newcastle Institute of Public Health–
Hunter Medical Research Institute through the New South Wales Health
Department Capacity Building and Infrastructure Grant.
* Corresponding author. Tel.: ϩ86-25-8375-9341; fax: ϩ86-25-8375-
9341.
E-mail address: zumins@vip.sina.com (Z. Shi).
Nutrition 24 (2008) 977–984
www.elsevier.com/locate/nut
0899-9007/08/$ – see front matter © 2008 Elsevier Inc. All rights reserved.
doi:10.1016/j.nut.2008.05.002