RESUMO
AIM: To comprehensively examine the associations of childhood and adulthood body size, and child-to-adult body size change with adult leucocyte telomere length (LTL). METHODS: We included 453 602 participants from the UK Biobank. Childhood body size at the age of 10 years was collected through a questionnaire. Adulthood body size was assessed using body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), fat mass index (FMI), and fat-free mass index (FFMI). RESULTS: Individuals with plumper body size in childhood exhibited shorter LTL in adulthood (-0.0086 [-0.0017, -0.0004]). Adulthood BMI (-0.0286 [-0.0315, -0.0258]), WC (-0.0271 [-0.0303, -0.0238]), WHR (-0.0269 [-0.0308, -0.0230]) and FMI (-0.0396 [-0.0438, -0.0351]) were negatively associated with LTL, whereas FFMI (0.0095 [0.0039, 0.0152]) was positively associated with LTL. Compared to individuals consistently having an average/normal weight in both childhood and adulthood, those who maintained or developed overweight/obesity from childhood to adulthood had a shorter adult LTL, regardless of childhood body size. Notably, the LTL shortening effect was not observed in individuals with plumper body size in childhood but normal weight in adulthood. CONCLUSIONS: Childhood and adulthood obesity are both associated with LTL shortening in adulthood. Transitioning to or maintaining overweight/obese status from childhood to adulthood is associated with shorter adult LTL, whereas this effect can be reversed if plumper children become normal weight.
RESUMO
BACKGROUND: Previous studies have linked single metal to hemoglobin levels in children and adolescents; however, studies with regards to metal mixtures are still limited. OBJECTIVE: We aimed to investigate the associations of single metal and metal mixtures with hemoglobin levels in children and adolescents. METHODS: We conducted a cross-sectional study of 2064 children and adolescents aged 6 to 19 years in Liuzhou, China in 2018. The concentrations of 15 metals in urine were determined by inductively coupled plasma mass spectrometry. Generalized linear regression and weighted quantile sum (WQS) regression were used to estimate the associations of single metal and metal mixtures with hemoglobin levels, respectively. RESULTS: The multivariable-adjusted ß-values for the highest versus the first quartiles of urinary metal concentrations were - 1.57 (95 % confidence interval [CI]: -3.01, -0.13) for chromium, -2.47 (95 % CI: -3.90, -1.05) for nickel and 1.88 (95 % CI: 0.49, 3.28) for copper. In addition, we found a significant negative association between the WQS index and hemoglobin levels (adjusted ß = -0.93, 95 % CI: -1.69, -0.19), with nickel contributing the most to the WQS index at 59.0 %. Subgroup analyses showed that exposure to urinary nickel or metal mixtures were associated with decreased hemoglobin levels in adolescents, but not in children (all Pinteration < 0.001). CONCLUSION: Among children and adolescents, urinary chromium and nickel concentrations were associated with decreased hemoglobin levels, while copper showed a positive relationship. Moreover, a negative association was observed between exposure to metal mixtures and hemoglobin levels. These findings need to be further validated in prospective studies.