Maternal vitamin A supplementation increases natural antibody concentrations of preadolescent offspring in rural Nepal

Vitamin supplements: Are they associated with immune status?

BACKGROUND & AIMS

Vitamins are essential nutrients, taken in very small amounts (0.01-100 mg a day). Associations between vitamin supplement intake or status and the immune system are far from consensual. Our aim was to understand the association between vitamin supplements and the immune system, namely regarding lymphocyte count and immunoglobulin levels against infectious pathogens.

METHODS

Cross-sectional study using data from the first follow-up of the CoLaus|PsyCoLaus study (April 2009 to September 2012). Participants were categorized as vitamin users and non-users. Serostatus for 15 viruses, six bacteria, and one parasite was assessed. Data for inflammatory markers (hs-CRP, IL-1β, IL-6, and TNF-α) and blood elements were also collected.

RESULTS

Of the initial 5064 participants, 3769 (74.5 %, mean age 58.3 ± 10.5 years, 53.6 % women) were retained for serostatus. On bivariate analysis, participants taking vitamins presented with higher positivity levels in three markers and lower positivity levels in two, but those differences were no longer statistically significant after multivariable analysis. 4489 participants (88.6 %, mean age 57.7 ± 10.5 years, 53.2 % women) had data for inflammatory markers; no association was found between vitamin supplement use and inflammatory markers both on bivariate and multivariable analysis. Finally, 3349 participants (66.1 %, mean age 57.3 ± 10.3 years, 53.1 % women) had data for blood elements; on bivariate analysis, vitamin supplement users had lower levels of haemoglobin and lymphocytes, but those differences were no longer significant after multivariable adjustment.

CONCLUSION

In this cross-sectional, population-based study, we found no association between vitamin supplement use and markers of immune status.

Micronutrient status during pregnancy is associated with child immune status in rural Bangladesh

Background

Poor immune function increases children's risk of infection and mortality. Several maternal factors during pregnancy may affect infant immune function during the postnatal period.

Objectives

We aimed to evaluate whether maternal micronutrients, stress, estriol, and immune status during the first or second trimester of pregnancy were associated with child immune status in the first two years after birth.

Methods

We conducted observational analyses within the water, sanitation, and hygiene (WASH) Benefits Bangladesh randomized controlled trial. We measured biomarkers in 575 pregnant women and postnatally in their children. Maternal biomarkers measured during the first and second trimester of pregnancy included nutrition status via vitamin D (25-hydroxy-D [25(OH)D]), ferritin, soluble transferrin receptor (sTfR), and retinol-binding protein (RBP); cortisol; estriol. Immune markers were assessed in pregnant women at enrollment and their children at ages 14 and 28 mo, including C-reactive protein (CRP), alpha-1-acid glycoprotein (AGP), and 13 cytokines (including IFN-γ). We generated a standardized sum score of log-transformed cytokines. We analyzed IFN-γ individually because it is a critical immunoregulatory cytokine. All outcomes were prespecified. We used generalized additive models and reported the mean difference and 95% confidence intervals at the 25th and 75th percentiles of exposure distribution.

Results

At child age 14 mo, concentrations of maternal RBP were inversely associated with the cytokine sum score in children (-0.34 adjusted difference between the 25th and 75th percentile [95% confidence interval -0.61, -0.07]), and maternal vitamin A deficiency was positively associated with the cytokine sum score in children (1.02 [0.13, 1.91]). At child age of 28 mo, maternal RBP was positively associated with IFN-γ in children (0.07 [0.01, 0.14]), whereas maternal vitamin A deficiency was negatively associated with child AGP (-0.07 [-0.13, -0.02]). Maternal iron deficiency was associated with higher AGP concentrations in children at age 14 mo (0.13 [0.04, 0.23]), and maternal sTfR concentrations were positively associated with child CRP concentrations at age 28 mo (0.18 [0, 0.36]).

Conclusion

Maternal deficiencies in vitamin A or iron during the first 2 trimesters of pregnancy may shape the trajectory of a child's immune status.

Fat-soluble vitamins: updated review of their role and orchestration in human nutrition throughout life cycle with sex differences

Age and Gender are vital determinants for the micronutrient demands of normal indviduals. Among these micronutrients are vitamins that are required in small amounts for optimum metabolism, homeostasis, and a healthy lifestyle, acting as coenzymes in several biochemical reactions. The majority of previous studies have examined such issues that relates to a specific vitamin or life stage, with the majority merely reporting the effect of either excess or deficiency. Vitamins are classified into water-soluble and fat-soluble components. The fat-soluble vitamins include vitamins (A, D, E, and K). Fat-soluble vitamins were found to have an indisputable role in an array of physiological processes such as immune regulation, vision, bone and mental health. Nonetheless, the fat-soluble vitamins are now considered a prophylactic measurement for a multitude of diseases such as autism, rickets disease, gestational diabetes, and asthma. Herein, in this review, a deep insight into the orchestration of the four different fat-soluble vitamins requirements is presented for the first time across the human life cycle beginning from fertility, pregnancy, adulthood, and senility with an extensive assessment ofthe interactions among them and their underlying mechanistic actions. The influence of sex for each vitamin is also presented at each life stage to highlight the different daily requirements and effects.

Immunodeficiency Accelerates Vitamin A Deficiency

BACKGROUND

Vitamin A deficiency increases susceptibility to infection caused by impaired immune function.

OBJECTIVES

We investigated whether immunodeficiency could facilitate the development of vitamin A deficiency.

METHODS

Vitamin A deficiency was followed in 2 mouse models of immunodeficiency: the athymic nude mouse (nu/nu) and the humoral immunodeficient SENCAR (SENsitive to CARcinogenesis) mouse. Vitamin A deficiency was also monitored in outbred Balb/c and in NIH mice. The monitoring of vitamin A deficiency was done after feeding the mice and their mothers a semisynthetic, vitamin A-deficient diet from birth of the experimental mice. These mice were weaned onto the same deficient diet at 3-4 wk of age, while control groups were fed the same diet containing 3 μg retinoic acid per gram of diet.

RESULTS

The immunodeficient nu/nu and SENCAR mice developed vitamin A deficiency earlier than either the heterozygous nu/+ controls or the Balb/c and NIH strains. In female mice, symptoms included depletion of liver retinol and retinyl palmitate, squamous metaplasia of the uterus, and death. Male mice lost weight more frequently and sooner than female mice, in which mortality generally occurred in the absence of loss of body weight. Pairwise comparisons using Tukey's honest significant difference test of the nu/nu and SENCAR mice versus the Balb/c and NIH mice showed a faster loss of retinol and retinyl palmitate in all pairs (P ≤ 0.0001) except for retinol when comparing nu/nu and NIH strains (P = 0.3383).

CONCLUSIONS

Our findings are consistent with an increased usage of liver retinol and retinyl palmitate in the immunocompromised nu/nu and in the immunodeficient SENCAR mice and suggest that compensatory mechanisms dependent on vitamin A utilization are called upon to rescue immunodeficiency both in the T-cell-deficient phenotype of the nu/nu mice and in the humoral immunodeficient SENCAR mice.

Safety and efficacy of supplements in pregnancy

Pregnancy is a time where expectant mothers often focus on their diet to improve their own health and to preserve the future health of their children. There is much conflicting information in the public domain about the safety and/or efficacy of nutritional supplements during pregnancy. Despite this, the market for supplements is growing. This review discusses the roles of critical nutrients in pregnancy and the available evidence on the use of supplements to reduce risks and improve maternal and fetal outcomes. Recommendations are made for pregnant women, taking into account safety data and tolerable upper intakes set for pregnant women. It is important for dieticians, nutritionists, physicians, and other healthcare providers to be able to offer accurate and evidence-based advice on supplement use in pregnancy. Routine supplementation may not be necessary for all, but individuals at risk are identified.

Preterm neonatal immunology at the intestinal interface

Fetal and neonatal development represents a critical window for setting a path toward health throughout life. In this review, we focus on intestinal immunity, how it develops, and its implications for subsequent neonatal diseases. We discuss maternal nutritional and environmental exposures that dictate outcomes for the developing fetus. Although still controversial, there is evidence in support of an in utero microbiome. Specific well-intentioned and routine applications of antibiotics, steroids, and surgical interventions implemented before, during, and after birth skew the neonate towards pro-inflammatory dysbiosis. Shortly after birth, a consortium of maternal and environmentally derived bacteria, through cross-talk with the developing host immune system, takes center stage in developing or disrupting immune homeostasis at the intestinal interface. We also examine subsequent immunological cross-talks, which involve neonatal myeloid and lymphoid responses, and their potential impacts on health and disease such as necrotizing enterocolitis and sepsis, especially critical disease entities for the infant born preterm.

Effects of Maternal Prenatal Multi-Micronutrient Supplementation on Growth and Development until 3 Years of Age

At present, there is insufficient evidence on whether prenatal multi-micronutrient (MM) supplementation can be an antenatal nutritional intervention or not. This study aimed to explore the sustained effect of prenatal MM supplementation on early childhood health. A total of 939 mother–offspring pairs were followed up in the study between 2015 to 2018 in Changsha, China. Information was mainly collected through household surveys at the ages of 1, 3, 6, 8, 12, 18, 24, and 36 months. General linear models and generalized estimating equation models were used to estimate the effects of maternal prenatal MM compared with IFA supplementation on infant growth and development. Offspring of women who used prenatal MM compared with IFA supplements had lower weight-for-age z score (WAZ) (adjusted β: −0.23, 95% CI: (−0.40, −0.06)) and weight-for-length z score (WLZ) (adjusted β: −0.20, 95% CI: (−0.37, −0.02)) at 3 months old, but a reduced risk of obesity at birth (aRR: 0.30, 95% CI: 0.11–0.78) and being overweight at 3 months old (aRR: 0.52, 95% CI: 0.32–0.84). Moreover, offspring of women who used prenatal MM compared with IFA supplements had significantly higher scores for communication (adjusted β: 0.41, 95% CI: 0.61–0.21), gross motor (adjusted β: 0.68, 95% CI: 0.49–0.88), fine motor (adjusted β: 1.64, 95% CI: 1.45–1.84), problem solving (adjusted β: 0.29, 95% CI: 0.10–0.49), and personal–social (adjusted β: 0.90, 95% CI: 0.70–1.10) skills at 36 months old. Prenatal MM supplementation could result in better infant growth in the first few months of life and improve development scores at the age of 3 years compared with IFA supplementation.

Predictors of vitamin A status among pregnant women in Western Brazilian Amazon

Determining the predictors of serum retinol at mid-pregnancy is relevant for planning interventions aimed at improving vitamin A status of pregnant women and their offspring. This prospective study assessed predictors of serum retinol at the beginning of the third trimester of pregnancy. We enrolled 442 pregnant women living in the urban area of Cruzeiro do Sul, Western Brazilian Amazon. Demographic, socio-economic, environmental and clinical characteristics as well as obstetric history, anthropometric, dietary and biochemical data, including serum retinol, were gathered between 16 and 20 gestational weeks. Serum retinol also measured at the beginning of the third trimester of pregnancy (approximately 28 gestational weeks) was the outcome of interest. Multiple linear regression models were used to evaluate associations with the outcome. Overall, the following variables explained serum retinol at the beginning of the third trimester of pregnancy in the adjusted model (R 2 = 11·1 %): seasonality (winter season - November to April; β=0·134; 95 % CI 0·063, 0·206), weekly consumption of Amazonian fruits (β=0·087; 95 % CI 0·012, 0·162) and retinol concentrations between 16 and 20 gestational weeks (β=0·045; 95 % CI 0·016, 0·074) were positively associated, whereas having a smoker in the house was negatively associated (β=-0·087; 95 % CI: -0·166, -0·009). Consumption of pro-vitamin A-rich fruits by pregnant women should be encouraged. Passive smoking may play a role in decreasing vitamin A status as a proxy of smoking exposure during pregnancy.

Ethical implications of excessive cluster sizes in cluster randomised trials

The cluster randomised trial (CRT) is commonly used in healthcare research. It is the gold-standard study design for evaluating healthcare policy interventions. A key characteristic of this design is that as more participants are included, in a fixed number of clusters, the increase in achievable power will level off. CRTs with cluster sizes that exceed the point of levelling-off will have excessive numbers of participants, even if they do not achieve nominal levels of power. Excessively large cluster sizes may have ethical implications due to exposing trial participants unnecessarily to the burdens of both participating in the trial and the potential risks of harm associated with the intervention. We explore these issues through the use of two case studies. Where data are routinely collected, available at minimum cost and the intervention poses low risk, the ethical implications of excessively large cluster sizes are likely to be low (case study 1). However, to maximise the social benefit of the study, identification of excessive cluster sizes can allow for prespecified and fully powered secondary analyses. In the second case study, while there is no burden through trial participation (because the outcome data are routinely collected and non-identifiable), the intervention might be considered to pose some indirect risk to patients and risks to the healthcare workers. In this case study it is therefore important that the inclusion of excessively large cluster sizes is justifiable on other grounds (perhaps to show sustainability). In any randomised controlled trial, including evaluations of health policy interventions, it is important to minimise the burdens and risks to participants. Funders, researchers and research ethics committees should be aware of the ethical issues of excessively large cluster sizes in cluster trials.

They Are What You Eat: Can Nutritional Factors during Gestation and Early Infancy Modulate the Neonatal Immune Response?

The ontogeny of the human immune system is sensitive to nutrition even in the very early embryo, with both deficiency and excess of macro- and micronutrients being potentially detrimental. Neonates are particularly vulnerable to infectious disease due to the immaturity of the immune system and modulation of nutritional immunity may play a role in this sensitivity. This review examines whether nutrition around the time of conception, throughout pregnancy, and in early neonatal life may impact on the developing infant immune system.

A retrospective analysis of a societal experiment among the Danish population suggests that exposure to extra doses of vitamin A during fetal development may lower type 2 diabetes mellitus (T2DM) risk later in life

Vitamin A deficiency has been associated with impaired fetal pancreatic development and increased risk of developing type 2 diabetes mellitus (T2DM). In 1962, mandatory margarine fortification with vitamin A was increased by 25 % in Denmark. We aimed to determine whether offspring of mothers who had been exposed to the extra vitamin A from fortification during pregnancy had a lower risk of developing T2DM in adult life, compared with offspring of mothers exposed to less vitamin A. Individuals from birth cohorts with the higher prenatal vitamin A exposure (born 1 December 1962-31 March 1964) and those with lower prenatal exposure (born 1 September 1959-31 December 1960) were followed up with regard to development of T2DM before 31 December 2012 in the Danish National Diabetes Registry and National Patient Register. Logistic and Cox regression analyses were performed to determine the risk of T2DM by vitamin A exposure level. A total of 193 803 individuals were followed up until midlife. Our results showed that individuals exposed prenatally to extra vitamin A from fortified margarine had a lower risk of developing T2DM than those exposed to lower levels: OR 0·88; 95 % CI 0·81, 0·95, P=0·001, after adjustment for sex. Fetal exposure to small, extra amounts of vitamin A from food fortification may reduce the risk of T2DM. These results may have public health relevance, as they demonstrate that one of the most costly chronic diseases may be prevented by food fortification - a simple and affordable public health nutrition intervention.

Role of Vitamin A/Retinoic Acid in Regulation of Embryonic and Adult Hematopoiesis

Vitamin A is an essential micronutrient throughout life. Its physiologically active metabolite retinoic acid (RA), acting through nuclear retinoic acid receptors (RARs), is a potent regulator of patterning during embryonic development, as well as being necessary for adult tissue homeostasis. Vitamin A deficiency during pregnancy increases risk of maternal night blindness and anemia and may be a cause of congenital malformations. Childhood Vitamin A deficiency can cause xerophthalmia, lower resistance to infection and increased risk of mortality. RA signaling appears to be essential for expression of genes involved in developmental hematopoiesis, regulating the endothelial/blood cells balance in the yolk sac, promoting the hemogenic program in the aorta-gonad-mesonephros area and stimulating eryrthropoiesis in fetal liver by activating the expression of erythropoietin. In adults, RA signaling regulates differentiation of granulocytes and enhances erythropoiesis. Vitamin A may facilitate iron absorption and metabolism to prevent anemia and plays a key role in mucosal immune responses, modulating the function of regulatory T cells. Furthermore, defective RA/RARα signaling is involved in the pathogenesis of acute promyelocytic leukemia due to a failure in differentiation of promyelocytes. This review focuses on the different roles played by vitamin A/RA signaling in physiological and pathological mouse hematopoiesis duddurring both, embryonic and adult life, and the consequences of vitamin A deficiency for the blood system.

Maternal Micronutrient Supplementation and Long Term Health Impact in Children in Rural Bangladesh

Background

Limited data is available on the role of prenatal nutritional status on the health of school-age children. We aimed to determine the impact of maternal micronutrient supplementation on the health status of Bangladeshi children.

Methods

Children (8.6–9.6 years; n = 540) were enrolled from a longitudinal mother-child cohort, where mothers were supplemented daily with either 30mg iron and 400μg folic acid (Fe30F), or 60mg iron and 400μg folic acid (Fe60F), or Fe30F including 15 micronutrients (MM), in rural Matlab. Blood was collected from children to determine the concentration of hemoglobin (Hb) and several micronutrients. Anthropometric and Hb data from these children were also available at 4.5 years of age and mothers at gestational week (GW) 14 and 30.

Results

MM supplementation significantly improved (p≤0.05) body mass index-for-age z-score (BAZ), but not Hb levels, in 9 years old children compared to the Fe30F group. MM supplementation also reduced markers of inflammation (p≤0.05). About 28%, 35% and 23% of the women were found to be anemic at GW14, GW30 and both time points, respectively. The prevalence of anemia was 5% and 15% in 4.5 and 9 years old children, respectively. The adjusted odds of having anemia in 9 year old children was 3-fold higher if their mothers were anemic at both GW14 and GW30 [Odds Ratio (OR) = 3.05; 95% Confidence Interval (CI) 1.42, 6.14, P = 0.002] or even higher if they were also anemic at 4.5 years of age [OR = 5.92; 95% CI 2.64, 13.25; P<0.001].

Conclusion

Maternal micronutrient supplementation imparted beneficial effects on child health. Anemia during pregnancy and early childhood are important risk factors for the occurrence of anemia in school-age children.

Vitamin supplementation for preventing miscarriage

BACKGROUND

Miscarriage is a common complication of pregnancy that can be caused by a wide range of factors. Poor dietary intake of vitamins has been associated with an increased risk of miscarriage, therefore supplementing women with vitamins either prior to or in early pregnancy may help prevent miscarriage.

OBJECTIVES

The objectives of this review were to determine the effectiveness and safety of any vitamin supplementation, on the risk of spontaneous miscarriage.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (6 November 2015) and reference lists of retrieved studies.

SELECTION CRITERIA

All randomised and quasi-randomised trials comparing supplementation during pregnancy with one or more vitamins with either placebo, other vitamins, no vitamins or other interventions. We have included supplementation that started prior to conception, periconceptionally or in early pregnancy (less than 20 weeks' gestation).

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed trials for inclusion, extracted data and assessed trial quality. We assessed the quality of the evidence using the GRADE approach. The quality of evidence is included for numerical results of outcomes included in the 'Summary of findings' tables.

MAIN RESULTS

We included a total of 40 trials (involving 276,820 women and 278,413 pregnancies) assessing supplementation with any vitamin(s) starting prior to 20 weeks' gestation and reporting at least one primary outcome that was eligible for the review. Eight trials were cluster-randomised and contributed data for 217,726 women and 219,267 pregnancies in total.Approximately half of the included trials were assessed to have a low risk of bias for both random sequence generation and adequate concealment of participants to treatment and control groups. Vitamin C supplementation There was no difference in the risk of total fetal loss (risk ratio (RR) 1.14, 95% confidence interval (CI) 0.92 to 1.40, seven trials, 18,949 women; high-quality evidence); early or late miscarriage (RR 0.90, 95% CI 0.65 to 1.26, four trials, 13,346 women; moderate-quality evidence); stillbirth (RR 1.31, 95% CI 0.97 to 1.76, seven trials, 21,442 women; moderate-quality evidence) or adverse effects of vitamin supplementation (RR 1.16, 95% CI 0.39 to 3.41, one trial, 739 women; moderate-quality evidence) between women receiving vitamin C with vitamin E compared with placebo or no vitamin C groups. No clear differences were seen in the risk of total fetal loss or miscarriage between women receiving any other combination of vitamin C compared with placebo or no vitamin C groups. Vitamin A supplementation No difference was found in the risk of total fetal loss (RR 1.01, 95% CI 0.61 to 1.66, three trials, 1640 women; low-quality evidence); early or late miscarriage (RR 0.86, 95% CI 0.46 to 1.62, two trials, 1397 women; low-quality evidence) or stillbirth (RR 1.29, 95% CI 0.57 to 2.91, three trials, 1640 women; low-quality evidence) between women receiving vitamin A plus iron and folate compared with placebo or no vitamin A groups. There was no evidence of differences in the risk of total fetal loss or miscarriage between women receiving any other combination of vitamin A compared with placebo or no vitamin A groups. Multivitamin supplementation There was evidence of a decrease in the risk for stillbirth among women receiving multivitamins plus iron and folic acid compared iron and folate only groups (RR 0.92, 95% CI 0.85 to 0.99, 10 trials, 79,851 women; high-quality evidence). Although total fetal loss was lower in women who were given multivitamins without folic acid (RR 0.49, 95% CI 0.34 to 0.70, one trial, 907 women); and multivitamins with or without vitamin A (RR 0.60, 95% CI 0.39 to 0.92, one trial, 1074 women), these findings included one trial each with small numbers of women involved. Also, they include studies where the comparison groups included women receiving either vitamin A or placebo, and thus require caution in interpretation.We found no difference in the risk of total fetal loss (RR 0.96, 95% CI 0.93 to 1.00, 10 trials, 94,948 women; high-quality evidence) or early or late miscarriage (RR 0.98, 95% CI 0.94 to 1.03, 10 trials, 94,948 women; moderate-quality evidence) between women receiving multivitamins plus iron and folic acid compared with iron and folate only groups.There was no evidence of differences in the risk of total fetal loss or miscarriage between women receiving any other combination of multivitamins compared with placebo, folic acid or vitamin A groups. Folic acid supplementation There was no evidence of any difference in the risk of total fetal loss, early or late miscarriage, stillbirth or congenital malformations between women supplemented with folic acid with or without multivitamins and/or iron compared with no folic acid groups. Antioxidant vitamins supplementation There was no evidence of differences in early or late miscarriage between women given antioxidant compared with the low antioxidant group (RR 1.12, 95% CI 0.24 to 5.29, one trial, 110 women).

AUTHORS' CONCLUSIONS

Taking any vitamin supplements prior to pregnancy or in early pregnancy does not prevent women experiencing miscarriage. However, evidence showed that women receiving multivitamins plus iron and folic acid had reduced risk for stillbirth. There is insufficient evidence to examine the effects of different combinations of vitamins on miscarriage and miscarriage-related outcomes.

Micronutrient deficiencies in pregnancy worldwide: health effects and prevention

Micronutrients, vitamins and minerals accessible from the diet, are essential for biologic activity. Micronutrient status varies widely throughout pregnancy and across populations. Women in low-income countries often enter pregnancy malnourished, and the demands of gestation can exacerbate micronutrient deficiencies with health consequences for the fetus. Examples of efficacious single micronutrient interventions include folic acid to prevent neural tube defects, iodine to prevent cretinism, zinc to reduce risk of preterm birth, and iron to reduce the risk of low birth weight. Folic acid and vitamin D might also increase birth weight. While extensive mechanistic and association research links multiple antenatal micronutrients with plausible materno-fetal health advantages, hypothesized benefits have often been absent, minimal or unexpected in trials. These findings suggest a role for population context in determining health responses and filling extensive gaps in knowledge. Multiple micronutrient supplements reduce the risks of being born with low birth weight, small for gestational age or stillborn in undernourished settings, and justify micronutrient interventions with antenatal care. Measurable health effects of gestational micronutrient exposure might persist into childhood but few data exists on potential long-term benefits. In this Review, we discuss micronutrient intake recommendations, risks and consequences of deficiencies, and the effects of interventions with a particular emphasis on offspring.

Sex differences in the early life correlates of natural antibody concentrations

Innate-like B1a lymphocytes arise from long-lived progenitors produced exclusively by fetal stem cells. Any insults coinciding with this early lymphopoietic wave could have a permanent impact on the B1a population and its unique protein products, the natural antibodies (NAb). We investigated early life nutritional influences on NAb concentrations of pre-adolescent children (n=290) in rural Nepal for whom we had extensive information on exposures from pregnancy and early infancy. Infant size and growth were strongly associated with NAb concentrations at 9-13 years of age among males (e.g., for neonatal weight: βBOYS=0.43; P<0.001), but not females (e.g., for neonatal weight: βGIRLS=-0.16; P=0.26). In females, season of birth was associated with NAb concentrations, with marked reductions among girls born during the pre-monsoon (March-May; βGIRLS=-0.39; P=0.01) and pre-harvest (September-November; βGIRLS=-0.35; P=0.03) seasons. Our findings suggest that nutritional or other environmental influences on immune development may vary by sex, with potential consequences for immune function during infancy and long-term risk of immune-mediated disease.