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.

Sociocultural Influences on Dietary Practices and Physical Activity Behaviors of Rural Adolescents-A Qualitative Exploration.

In the aftermath of nutrition transition and ever-increasing sedentarism, adolescents globally are exposed to negative health consequences. Diverse sociocultural influences play a critical role in their adoption of unhealthy dietary practices and suboptimal physical activity behaviors. Context-specific understandings of how these sociocultural influences shape adolescents' dietary and physical activity patterns in a rural, resource-limited setting remained elusive. Aiming to address the gap, this qualitative study explored adolescents' and mothers' perception of broader sociocultural aspects that sculpt the food choices, eating habits and physical activity behaviors of adolescents in Matlab, Bangladesh. Six digitally-recorded focus group discussions were transcribed verbatim, translated into English and analyzed thematically. Marked taste-driven dietary preference of adolescents and its prioritization within family by the mothers, popularity of street foods, better understanding of the importance of food hygiene and safety contrasting with narrow perception of balance and diversity in diet, peer influence along with deficient school and community food environment, internalization and rigidity of gender norms were found to be exerting major influence. The findings highlighted key targets for community-based nutrition interventions and endorsed thorough consideration of socio-cultural factors in formulating strategies to promote healthful eating and physical activity behaviors among the adolescents.