Yin Shaohua, Zhou Yubo, Li Hongtian, Cheng Zhihao, Zhang Yali, Zhang Le, Liu Jufen, Liu Jianmeng
1Institute of Reproductive and Child Health/National Health Commission Key Laboratory of Reproductive Health, Peking University Health Science Center, No. 38 Xueyuan Rd, Haidian District, Beijing, 100191 China.
2Department of Epidemiology and Biostatistics, School of Public Health, Peking University Health Science Center, Beijing, China.
Nutr Metab (Lond). 2020 Apr 19;17:32. doi: 10.1186/s12986-020-00448-w. eCollection 2020.
Infant anemia is prevalent in low- and middle-income countries. Maternal body mass index (BMI) is associated with serum ferritin in cord blood, but as yet has not been linked to infant anemia. The objective of this study was to examine the association of maternal BMI during early pregnancy with infant hemoglobin levels and anemia at 6 and 12 months in a Chinese birth cohort.
The prospective cohort included 17,193 mother-infant pairs. Maternal weight and height prior to 20 gestational weeks as well as infant hemoglobin at 6 and 12 months were measured following standard procedures, and BMI was calculated as weight in kilograms divided by the square of height in meters. Women were categorized into underweight, normal weight (reference), overweight, and obesity. Infant anemia was defined as hemoglobin < 11.0 g/dl. Fractional polynomial regression was used to examine the relation between maternal BMI and infant hemoglobin, joinpoint regression to identify breakpoints, and logistic regression to estimate odds ratios (ORs).
In the cohort, 1160 (6.8%) were anemic at 6 months and 904 (5.3%) at 12 months. An inverse U-shaped relation of maternal BMI with infant hemoglobin was found at 6 months, at their maximum at maternal BMI of 22.4 kg/m, and a similar relationship found again at 12 months. Maternal obesity rather than underweight was associated with an increased risk of anemia for infants at 6 months (adjusted OR 1.39, 95% CI 1.02, 1.88), but not at 12 months. Maternal anemia during mid-pregnancy augmented the risk at 6 months (adjusted OR 2.91, 95% CI 1.14, 7.46), but did not mediate the association ( = - 1.102, = 0.270).
Maternal BMI during early pregnancy is correlated with infant hemoglobin in an inverse U-shaped profile, and obesity increases infant anemia risk that is aggravated by maternal anemia during pregnancy. This study enriched the epidemiological evidence on the adverse effect of high maternal BMI on long-term health of offspring. Optimizing maternal weight in obstetric care is necessary to improve offspring health.
婴儿贫血在低收入和中等收入国家普遍存在。孕妇体重指数（BMI）与脐血血清铁蛋白有关，但尚未与婴儿贫血相关联。本研究的目的是在中国出生队列中，研究孕早期孕妇BMI与婴儿6个月和12个月时血红蛋白水平及贫血之间的关联。
前瞻性队列包括17193对母婴。按照标准程序测量孕20周前孕妇的体重和身高以及婴儿6个月和12个月时的血红蛋白，并计算BMI（体重千克数除以身高米数的平方）。将女性分为体重过轻、正常体重（参照组）、超重和肥胖。婴儿贫血定义为血红蛋白<11.0 g/dl。采用分数多项式回归分析孕妇BMI与婴儿血红蛋白之间的关系，采用连接点回归确定断点，采用逻辑回归估计比值比（OR）。
在该队列中，6个月时1160例（6.8%）贫血，12个月时904例（5.3%）贫血。发现孕妇BMI与婴儿6个月时的血红蛋白呈倒U形关系，孕妇BMI为22.4 kg/m²时达到最大值，12个月时再次发现类似关系。孕妇肥胖而非体重过轻与婴儿6个月时贫血风险增加有关（校正OR 1.39，95%CI 1.02，1.88），但12个月时无关。孕中期孕妇贫血增加了6个月时的风险（校正OR 2.91，95%CI 1.14，7.46），但未介导这种关联（= -1.102，= 0.270）。
孕早期孕妇BMI与婴儿血红蛋白呈倒U形相关，肥胖增加婴儿贫血风险，孕期孕妇贫血会加重这种风险。本研究丰富了孕妇高BMI对后代长期健康不利影响的流行病学证据。在产科护理中优化孕妇体重对改善后代健康很有必要。
