Prenatal and adolescent exposure to metals/metalloids and telomere dynamics at 14 years: Evidence from the Chitwan birth cohort

Telomeres are repetitive non-coding DNA sequences at chromosome ends that progressively shorten with each cell division, serving as markers of cellular aging. Recent studies have suggested that prenatal and postnatal exposure to metals/metalloids may influence telomere length (TL) attrition; however, longitudinal studies spanning the prenatal period to adolescence remain limited. We investigated whether prenatal and adolescent exposure to metals/metalloids (arsenic, lead, selenium, zinc, copper) predicts TL at 14 years of age. In 2008, pregnant mothers (n = 100) were recruited from Bharatpur General Hospital, Chitwan, Nepal, where questionnaire surveys and cord blood samples were collected. After 14 years, in 2022, their children (n = 74) were followed up. Cord blood and urine samples were analyzed for metals/metalloids concentrations using inductively coupled plasma tandem mass spectrometry (ICP-MS). TL was assessed by the quantitative real-time polymerase chain reaction using the dried blood spots and expressed as the T/S ratio. Cord blood concentration of arsenic, lead, selenium, zinc, or copper did not predict TL at 14 years of age. TL was positively associated with urinary selenium (β = 0.29, 95% CI: 0.01-0.58) and perceived neighborhood quality (β = 0.35, 95% CI: 0.10-0.60) in adolescents. Although the small sample size may have limited the power to detect modest associations, our study showed that cumulative or mixture exposure exhibited no significant associations with TL over 14 years of follow-up. In utero exposure to metals/metalloids did not predict TL in adolescence. Growth environment and selenium status emerged as important determinants of biological aging during this developmental stage.