Early Life Environmental Exposure to Cadmium, Lead, and Arsenic and Age at Menarche: A Longitudinal Mother-Child Cohort Study in Bangladesh.

BACKGROUND: Several metals act as endocrine disruptors, but there are few large longitudinal studies about associations with puberty onset. OBJECTIVES: We evaluated whether early life cadmium, lead, and arsenic exposure was associated with timing of menarche. METHODS: In a mother-child cohort in rural Bangladesh (n=935), the exposure was assessed by concentrations in maternal erythrocytes in early pregnancy and in girls' urine at 5 and 10 years of age using inductively coupled plasma mass spectrometry. The girls were interviewed twice, at average ages 13.3 [standard deviation (SD)=0.43] and 13.8 (SD=0.43) y, and the date of menarche, if present, was recorded. Associations were assessed using Kaplan-Meier analysis and multivariable-adjusted Cox regression. RESULTS: In total, 77% of the girls (n=717) had reached menarche by the second follow-up. The median age of menarche among all girls was 13.0 y (25th-75th percentiles: 12.4-13.7 y). At 10 years of age, median urinary cadmium was 0.25µg/L (5th-95th percentiles: 0.087-0.72µg/L), lead 1.6µg/L (0.70-4.2µg/L), and arsenic 54µg/L (19-395µg/L). Given the same age, girls in the highest quartile of urinary cadmium at 5 and 10 years of age had a lower rate of menarche than girls in the lowest quartile, with an adjusted hazard ratio of (HR) 0.80 (95% CI: 0.62, 1.01) at 5 years of age, and 0.77 (95% CI: 0.60, 0.98) at 10 years of age. This implies that girls in the highest cadmium exposure quartile during childhood had a higher age at menarche. Comparing girls in the highest to the lowest quartile of urinary lead at 10 years of age, the former had a higher rate of menarche [adjusted HR = 1.23 (95% CI: 0.97, 1.56)], implying lower age at menarche, whereas there was no association with urinary lead at 5 years of age. Girls born to mothers in the highest quartile of erythrocyte arsenic during pregnancy were less likely to have attained menarche than girls born to mothers in the lowest quartile [adjusted HR= 0.79 (95% CI: 0.62, 0.99)]. No association was found with girls' urinary arsenic exposure. DISCUSSION: Long-term childhood cadmium exposure was associated with later menarche, whereas the associations with child lead exposure were inconclusive. Maternal exposure to arsenic, but not cadmium or lead, was associated with later menarche. https://doi.org/10.1289/EHP11121.

A cohort study of the association between prenatal arsenic exposure and age at menarche in a rural area, Bangladesh.

BACKGROUND: Millions of individuals worldwide, particularly in Bangladesh, are exposed to arsenic, mainly through drinking water from tube wells. Arsenic is a reproductive toxicant, but there is limited knowledge of whether it influences pubertal development. OBJECTIVES: We evaluated the association between prenatal arsenic exposure and age at menarche. METHODS: This prospective study was based on data from two studies conducted in Matlab, Bangladesh-the Maternal and Infant Nutrition Interventions in Matlab (MINIMat) trial and the Health Consequences of Arsenic in Matlab (AsMat) study. We included 809 MINIMat girls who participated in assessing age at menarche from July 2016 to June 2017 and had prenatal arsenic exposure data through the AsMat study via measurements in tube well water used by the mothers during pregnancy. The exposure was categorized into <10, 10-49, 50-99, 100-199, and ≥200 µg/L. We used Kaplan-Meier and Cox proportional hazards analyses with adjustment for potential confounders to evaluate the association between arsenic exposure and age at menarche. The results were presented by adjusted hazards ratio (aHR) with a 95% confidence interval (CI). RESULTS: The median arsenic concentration in tube well water consumed by pregnant women was 80 µg/L (interquartile range 2-262 µg/L), and 55% drank water with concentrations above Bangladesh's acceptable value of 50 µg/L. The median age at menarche was 13.0 years. The unadjusted analysis revealed 3.2 months delay in menarche for girls exposed to arsenic concentrations ≥200 µg/L compared with the girl exposed to arsenic concentrations <10 µg/L. Girls exposed to the same higher arsenic concentrations were 23% (aHR 0.77, 95% CI: 0.63-0.95) less likely to have reached menarche than girls exposed to low arsenic concentrations. CONCLUSIONS: Increased levels of prenatal arsenic exposure were associated with older age at menarche. This delay may indicate endocrine disruptions that could potentially result in adverse health consequences in later life. This finding, along with other severe adverse health reinforces the need for arsenic mitigation at the population level.

Stunting, recovery from stunting and puberty development in the MINIMat cohort, Bangladesh.

AIM: This paper aimed to analyse the association between small for size at birth, stunting, recovery from stunting and pubertal development in a rural Bangladeshi cohort. METHODS: The participants were 994 girls and 987 boys whose mothers participated in the Maternal and Infant Nutrition Interventions in Matlab trial. The birth cohort was followed from birth to puberty 2001-2017. Pubertal development according to Tanner was self-assessed. Age at menarche was determined and in boys, consecutive height measurements were used to ascertain whether pubertal growth spurt had started. The exposures and outcomes were modelled by Cox's proportional hazards analyses and logistic regression. RESULTS: There was no difference in age at menarche between girls that were small or appropriate for gestational age at birth. Boys born small for gestational age entered their pubertal growth spurt later than those with appropriate weight. Children who were stunted had later pubertal development, age at menarche and onset of growth spurt than non-stunted children. Children who recovered from infant or early childhood stunting had similar pubertal development as non-stunted children. CONCLUSION: Infant and childhood stunting was associated with a later pubertal development. Recovery from stunting was not associated with earlier puberty in comparison with non-stunted children.

[The MINIMat study in Bangladesh: International research collaboration and research training with a perspective from foetus to future health]. / Från foster till framtida hälsa - MINIMat-studien i Bangladesh har halverat dödligheten hos spädbarn och gett bättre tillväxt och metabola markörer.

In South Asia, maternal and child undernutrition is common with consequences for short- and long-term health. In the MINIMat trial (Maternal and Infant Nutrition Interventions in Matlab) in Bangladesh 4436 pregnant women were allocated to early or later start of food supplements and different micronutrient alternatives. Children of mothers who received food supplementation from week 9 combined with multiple micronutrients showed a halved infant mortality rate. The early initiation of prenatal food supplementation reduced the risk of stunting up to five years and was associated with more favourable metabolic markers. The MINIMat study is run by icddr,b in Bangladesh and Uppsala University in collaboration with seven other universities. Twenty Ph.D. students have so far defended their theses and more than 100 scientific papers have been published.

Relative importance of prenatal and postnatal determinants of stunting: data mining approaches to the MINIMat cohort, Bangladesh.

INTRODUCTION: WHO has set a goal to reduce the prevalence of stunted child growth by 40% by the year 2025. To reach this goal, it is imperative to establish the relative importance of risk factors for stunting to deliver appropriate interventions. Currently, most interventions take place in late infancy and early childhood. This study aimed to identify the most critical prenatal and postnatal determinants of linear growth 0-24 months and the risk factors for stunting at 2 years, and to identify subgroups with different growth trajectories and levels of stunting at 2 years. METHODS: Conditional inference tree-based methods were applied to the extensive Maternal and Infant Nutrition Interventions in Matlab trial database with 309 variables of 2723 children, their parents and living conditions, including socioeconomic, nutritional and other biological characteristics of the parents; maternal exposure to violence; household food security; breast and complementary feeding; and measurements of morbidity of the mothers during pregnancy and repeatedly of their children up to 24 months of age. Child anthropometry was measured monthly from birth to 12 months, thereafter quarterly to 24 months. RESULTS: Birth length and weight were the most critical factors for linear growth 0-24 months and stunting at 2 years, followed by maternal anthropometry and parental education. Conditions after birth, such as feeding practices and morbidity, were less strongly associated with linear growth trajectories and stunting at 2 years. CONCLUSION: The results of this study emphasise the benefit of interventions before conception and during pregnancy to reach a substantial reduction in stunting.

Time trends and sociodemographic determinants of preterm births in pregnancy cohorts in Matlab, Bangladesh, 1990-2014.

INTRODUCTION: Preterm birth is the major cause of under-five mortality. Population-based data on determinants and proportions of children born preterm are limited, especially from low-income countries. This study aimed at assessing time trends and social, reproductive and environmental determinants of preterm births based on a population-based pregnancy cohort over 25 years in rural Bangladesh. METHODS: In this cohort study in Matlab, a rural area in Bangladesh, we used data from the Health and Demographic Surveillance System from 1990 to 2014. Gestational age at birth was based on the reported last menstrual period and verified by ultrasound assessments. Preterm birth proportions were assessed within strata of social and reproductive characteristics, and time series analysis was performed with decomposition for trend and seasonality. We also determined the prevented fractions of preterm birth reduction associated with social and demographic changes during the follow-up period. RESULTS: Analyses were based on 63 063 live births. Preterm birth decreased from 29% (95% CI 28.6 to 30.1) in 1990-1994 to 11% (95% CI 10.5 to 11.6) in 2010-2014. Low education, older age and multi-parity were associated with higher proportions of preterm births across the study period. Preterm births had a marked seasonal variation. A rapid increase in women's educational level and decrease in parity were associated with the decline in preterm births, and 27% of the reduction observed from 1990 to 2014 could be attributed to these educational and reproductive changes. CONCLUSION: The reduction in preterm birth was to a large extent associated with the sociodemographic transition, especially changes in maternal education and parity. The persistent seasonal variation in the proportion of preterm birth may reflect the environmental stressors for pregnant women across the study period. Continued investments in girls' education and family planning programmes may contribute to further reduction of preterm births in Bangladesh.

Cost-effectiveness of prenatal food and micronutrient interventions on under-five mortality and stunting: Analysis of data from the MINIMat randomized trial, Bangladesh.

INTRODUCTION: Nutrition interventions may have favourable as well as unfavourable effects. The Maternal and Infant Nutrition Interventions in Matlab (MINIMat), with early prenatal food and micronutrient supplementation, reduced infant mortality and were reported to be very cost-effective. However, the multiple micronutrients (MMS) supplement was associated with an increased risk of stunted growth in infancy and early childhood. This unfavourable outcome was not included in the previous cost-effectiveness analysis. The aim of this study is to evaluate whether the MINIMat interventions remain cost-effective in view of both favourable (decreased under-five-years mortality) and unfavourable (increased stunting) outcomes. METHOD: Pregnant women in rural Bangladesh, where food insecurity still is prevalent, were randomized to early (E) or usual (U) invitation to be given food supplementation and daily doses of 30 mg, or 60 mg iron with 400 µg of folic acid, or MMS with 15 micronutrients including 30 mg iron and 400 µg of folic acid. E reduced stunting at 4.5 years compared with U, MMS increased stunting at 4.5 years compared with Fe60, while the combination EMMS reduced infant mortality compared with UFe60. The outcome measure used was disability adjusted life years (DALYs), a measure of overall disease burden that combines years of life lost due to premature mortality (under five-year mortality) and years lived with disability (stunting). Incremental cost effectiveness ratios were calculated using cost data from already published studies. RESULTS: By incrementing UFe60 (standard practice) to EMMS, one DALY could be averted at a cost of US$24. CONCLUSION: When both favourable and unfavourable outcomes were included in the analysis, early prenatal food and multiple micronutrient interventions remained highly cost effective and seem to be meaningful from a public health perspective.

Stunted at 10 Years. Linear Growth Trajectories and Stunting from Birth to Pre-Adolescence in a Rural Bangladeshi Cohort.

BACKGROUND: Few studies in low-income settings analyse linear growth trajectories from foetal life to pre-adolescence. The aim of this study is to describe linear growth and stunting from birth to 10 years in rural Bangladesh and to analyse whether maternal and environmental determinants at conception are associated with linear growth throughout childhood and stunting at 10 years. METHODS AND FINDINGS: Pregnant women participating in the MINIMat trial were identified in early pregnancy and a birth cohort (n = 1054) was followed with 19 growth measurements from birth to 10 years. Analyses of baseline predictors and mean height-for-age Z-scores (HAZ) over time were modelled using GLMM. Logistic regression analysis was used to investigate the associations between baseline predictors and stunting (HAZ<-2) at 10 years. HAZ decreased to 2 years, followed by an increase up to 10 years, while the average height-for-age difference in cm (HAD) to the WHO reference median continued to increase up to 10 years. Prevalence of stunting was highest at 2 years (50%) decreasing to 29% at 10 years. Maternal height, maternal educational level and season of conception were all independent predictors of HAZ from birth to pre-adolescence (p<0.001) and stunting at 10 years. The highest probability to be stunted at 10 years was for children born by short mothers (<147.5 cm) (ORadj 2.93, 95% CI: 2.06-4.20), mothers with no education (ORadj 1.74, 95% CI 1.17-2.81) or those conceived in the pre-monsoon season (ORadj 1.94, 95% CI 1.37-2.77). CONCLUSIONS: Height growth trajectories and prevalence of stunting in pre-adolescence showed strong intergenerational associations, social differentials, and environmental influence from foetal life. Targeting women before and during pregnancy is needed for the prevention of impaired child growth.