Wells Jonathan C K, Marphatia Akanksha A, Manandhar Dharma S, Cortina-Borja Mario, Reid Alice M, Saville Naomi S
Population, Policy and Practice Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, London WC1N 1EH, UK.
Department of Geography, University of Cambridge, Cambridge CB2 3EN, UK.
Evol Med Public Health. 2022 Jul 25;10(1):325-338. doi: 10.1093/emph/eoac025. eCollection 2022.
Women's nutritional status is important for their health and reproductive fitness. In a population where early marriage is common, we investigated how women's nutritional status is associated with their age at marriage (marking a geographical transfer between households), and at first pregnancy.
We used data from a cluster-randomized control trial from lowland Nepal ( = 4071). Outcomes including body mass index (BMI) were measured in early pregnancy and trial endpoint, after delivery. We fitted mixed-effects linear and logistic regression models to estimate associations of age at marriage and age at pregnancy with outcomes, and with odds of chronic energy deficiency (CED, BMI <18.5 kg/m), at both timepoints.
BMI in early pregnancy averaged 20.9 kg/m, with CED prevalence of 12.5%. In 750 women measured twice, BMI declined 1.2 (95% confidence interval 1.1, 1.3) kg/m between early pregnancy and endpoint, when CED prevalence was 35.5%. Early pregnancy was associated in dose-response manner with poorer nutritional status. Early marriage was independently associated with poorer nutritional status among those pregnant ≤15 years, but with better nutritional status among those pregnant ≥19 years.
The primary determinant of nutritional status was age at pregnancy, but this association also varied by marriage age. Our results suggest that natal households may marry their daughters earlier if food insecure, but that their nutritional status can improve in the marital household if pregnancy is delayed. Marriage age therefore determines which household funds adolescent weight gain, with implications for Darwinian fitness of the members of both households.
女性的营养状况对其健康和生殖健康至关重要。在早婚现象普遍的人群中，我们调查了女性的营养状况如何与其结婚年龄（标志着家庭之间的地域转移）以及首次怀孕年龄相关。
我们使用了来自尼泊尔低地的一项整群随机对照试验的数据（n = 4071）。在怀孕早期和分娩后的试验终点测量了包括体重指数（BMI）在内的结果。我们拟合了混合效应线性和逻辑回归模型，以估计结婚年龄和怀孕年龄与各时间点结果以及慢性能量缺乏（CED，BMI <18.5 kg/m²）几率之间的关联。
怀孕早期的BMI平均为20.9 kg/m²，CED患病率为12.5%。在750名被测量两次的女性中，怀孕早期至终点时BMI下降了1.2（95%置信区间1.1，1.3）kg/m²，此时CED患病率为35.5%。怀孕早期与较差的营养状况呈剂量反应关系。早婚在怀孕≤15岁的人群中与较差的营养状况独立相关，但在怀孕≥19岁的人群中与较好的营养状况相关。
营养状况的主要决定因素是怀孕年龄，但这种关联也因结婚年龄而异。我们的结果表明，如果粮食不安全，娘家可能会更早地将女儿嫁出，但如果怀孕延迟，她们在婆家的营养状况可能会改善。因此，结婚年龄决定了哪个家庭为青少年体重增加提供资金，这对两个家庭成员的达尔文适应性有影响。
