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BACKGROUND: Manganese (Mn) plays a significant role in both human health and global industries. Epidemiological studies of exposed populations demonstrate a dose-dependent association between Mn and neuromotor effects ranging from subclinical effects to a clinically defined syndrome. However, little is known about the relationship between early life Mn biomarkers and adolescent postural balance. OBJECTIVES: This study investigated the associations between childhood and adolescent Mn biomarkers and adolescent postural balance in participants from the longitudinal Marietta Communities Actively Researching Exposures Study (CARES) cohort. METHODS: Participants were recruited into CARES when they were 7-9 y old, and reenrolled at 13-18 years of age. At both time points, participants provided samples of blood, hair, and toenails that were analyzed for blood Mn and lead (Pb), serum cotinine, hair Mn, and toenail Mn. In adolescence, participants completed a postural balance assessment. Greater sway indicates postural instability (harmful effect), whereas lesser sway indicates postural stability (beneficial effect). Multivariable linear regression models were conducted to investigate the associations between childhood and adolescent Mn biomarkers and adolescent postural balance adjusted for age, sex, height--weight ratio, parent/caregiver intelligence quotient, socioeconomic status, blood Pb, and serum cotinine. RESULTS: CARES participants who completed the adolescent postural balance assessment (n=123) were 98% White and 54% female and had a mean age of 16 y (range: 13-18 y). In both childhood and adolescence, higher Mn biomarker concentrations were significantly associated with greater adolescent sway measures. Supplemental analyses revealed sex-specific associations; higher childhood Mn biomarker concentrations were significantly associated with greater sway in females compared with males. DISCUSSION: This study found childhood and adolescent Mn biomarkers were associated with subclinical neuromotor effects in adolescence. This study demonstrates postural balance as a sensitive measure to assess the association between Mn biomarkers and neuromotor function. https://doi.org/10.1289/EHP13381, Introduction Manganese (Mn) is an element that exists ubiquitously in the environment, often in combination with other elements. (1) Mn plays a significant role in both human health and global [...]

Objective Exposure to ultrafine particles (UFP) in secondhand smoke (SHS) and traffic-related air pollution (TRAP) may elicit chronic inflammation. It was hypothesized that the association between these exposures would be potentiated in overweight versus normal-weight children. Methods Average lifetime exposure to TRAP and SHS and objective, physician-diagnosed asthma were determined for 575 children at age 7. Overweight was defined as having a body mass index (BMI) >85th percentile for age and gender. The association between TRAP and SHS exposure and asthma was examined by logistic regression stratified by BMI. Results A total of 131 children were overweight; the prevalence of asthma was 24.4% and 14.2% among overweight and normal-weight children, respectively. Exposure to SHS was significantly associated with asthma among overweight (adjusted odds ratio [adjOR] = 3.0; 95% confidence interval [CI] = 1.2, 7.4) but not normal-weight children (adjOR = 1.1; 95% CI = 0.4, 2.7). In contrast, TRAP was significantly associated with asthma among normal-weight (adjOR = 1.8; 95% CI = 1.0, 3.4) but not overweight children (adjOR = 0.7; 95% CI = 0.4, 2.7). Conclusions The association between SHS and TRAP exposure and asthma is modified by children's weight. Children's time-activity patterns, including time spent indoors or outdoors, may vary by weight and play an important role in these UFP exposures. [ABSTRACT FROM AUTHOR]