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Obesity and iron deficiency: a quantitative meta‐analysis
Author(s) -
Zhao L.,
Zhang X.,
Shen Y.,
Fang X.,
Wang Y.,
Wang F.
Publication year - 2015
Publication title -
obesity reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.845
H-Index - 162
eISSN - 1467-789X
pISSN - 1467-7881
DOI - 10.1111/obr.12323
Subject(s) - overweight , transferrin saturation , medicine , iron deficiency , obesity , odds ratio , confidence interval , meta analysis , ferritin , body mass index , subgroup analysis , anemia
Summary Hypoferraemia (i.e. iron deficiency) was initially reported among obese individuals several decades ago; however, whether obesity and iron deficiency are correlated remains unclear. Here, we evaluated the putative association between obesity and iron deficiency by assessing the concentration of haematological iron markers and the risks associated with iron deficiency in both obese (including overweight) subjects and non‐overweight participants. We performed a systematic search in the databases PubMed and Embase for relevant research articles published through D ecember 2014. A total of 26 cross‐sectional and case–control studies were analysed, comprising 13,393 overweight/obese individuals and 26,621 non‐overweight participants. Weighted or standardized mean differences of blood iron markers and odds ratio ( OR ) of iron deficiency were compared between the overweight/obese participants and the non‐overweight participants using a random‐effects model. Compared with the non‐overweight participants, the overweight/obese participants had lower serum iron concentrations (weighted mean difference [ WMD ]: −8.37 μg dL −1 ; 95% confidence interval [ CI ]: −11.38 to −5.36 μg dL −1 ) and lower transferrin saturation percentages ( WMD : 2.34%, 95% CI : −3.29% to −1.40%). Consistent with this finding, the overweight/obese participants had a significantly increased risk of iron deficiency ( OR : 1.31; 95% CI : 1.01–1.68). Moreover, subgroup analyses revealed that the method used to diagnose iron deficiency can have a critical effect on the results of the association test; specifically, we found a significant correlation between iron deficiency and obesity in studies without a ferritin‐based diagnosis, but not in studies that used a ferritin‐based diagnosis. Based upon these findings, we concluded that obesity is significantly associated with iron deficiency, and we recommend early monitoring and treatment of iron deficiency in overweight and obese individuals. Future longitudinal studies will help to test whether causal relationship exists between obesity and iron deficiency.