Association of Hemoglobin and Hematocrit Levels during Pregnancy and Maternal Dietary Iron Intake with Allergic Diseases in Children: The Japan Environment and Children's Study (JECS).

Limin Yang,Kiwako Yamamoto-Hanada,Minaho Nishizato,Mayako Saito-Abe,Kenji Matsumoto,Yukihiro Ohya,Mizuho Konishi,Hatoko Sasaki,Miori Sato,Hidetoshi Mezawa,Kazue Ishitsuka,Makoto Irahara

doi:10.3390/nu13030810

Limin Yang, Kiwako Yamamoto-Hanada + Show 10 more

Open Access

https://doi.org/10.3390/nu13030810

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Journal: Nutrients	Publication Date: Mar 1, 2021
Citations: 6	License type: CC BY 4.0

Affiliation: National Center For Child Health and Development

Abstract

Few epidemiologic studies have examined the role of maternal iron status in allergic diseases in offspring and findings have been inconsistent. We used a large birth cohort in Japan to explore the association of the markers for maternal iron status (maternal hemoglobin, hematocrit and dietary iron intake during pregnancy) with allergy development in offspring during early childhood. We analyzed information on children age 0–3 years from the Japan Environment and Children’s Study (JECS). We used logistic models and generalized estimating equation models to evaluate the effect of maternal hemoglobin and hematocrit levels and dietary iron intake on allergies in children. Models were also fitted with propensity score-matched datasets. Data were collected for a total of 91,247 mother–child pairs. The prevalence (95% confidence interval) of low hemoglobin and hematocrit was 14.0% (13.7–14.2%) and 12.5% (12.3–12.8%), respectively. After adjusting confounders, low hemoglobin and hematocrit during pregnancy were not associated with childhood allergic outcomes. Findings from models with propensity score-matched datasets also indicated that children born to mothers with low hemoglobin or hematocrit levels during pregnancy did not have a higher risk of developing allergic conditions at 3 years old. We found no meaningful associations between low energy adjusted maternal dietary iron intake and allergies in children. In conclusion, using birth cohort data, we found no evidence supporting an association of low maternal hemoglobin, hematocrit and low dietary iron intake with allergy symptoms during early childhood. Further studies with more suitable proxy markers for blood iron status are needed.

Highlights

Anemia is one of the most common complications in young women, especially during pregnancy
Our study population consisted of children between age 0 to 3 years participating in the Japan Environment and Children’s Study (JECS), a nationwide birth cohort study with 104,062 fetal records [25]
To explore whether a U-shaped relationship existed, we further developed logistic models with hemoglobin, hematocrit and energy adjusted maternal dietary iron intake treated as continuous variables

Summary

Introduction

Anemia is one of the most common complications in young women, especially during pregnancy. Anemia is considered a risk for many adverse maternal and perinatal outcomes, such as prematurity and low size or birth weight, peripartum blood loss, maternal depression, fetal impairment and maternal and fetal mortality. Anemia can be caused by genetic traits, inadequate food consumption, folate, or vitamin B12 and other diseases such as malaria, schistosomiasis, hookworm infection and HIV infection [1]. The most common cause of anemia is iron deficiency, which accounts for 50% of diagnoses [1]. In. 2011, the prevalence of anemia during pregnancy was 38% worldwide [1], of whom about. Pregnant women with a hemoglobin level less than 12 g/dL may experience “physiologic anemia of pregnancy”. It is generally considered that a hemoglobin concentration

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