Risk Factors for Lead Toxicity and its Effect on Neurobehavior in Indian Children.

Lead (Pb) is profoundly used heavy metal despite its known toxic effects. Children in particular are more susceptible to Pb toxicity. Thus, the present study was carried out to estimate the prevalence of lead toxicity in Indian children, to observe serum levels of biochemical parameters and to evaluate psychopathological implications of Pb toxicity using population specific scale-Childhood Psychopathological Measurement Schedule (CPMS) in children. Children between 9 and 15 years of age were included in the study (N = 70). Demographic details and information regarding the source of lead exposure were collected using a self-made questionnaire. All biochemical investigations were performed in Beckman Coulter Auto-analyser AU680 and Blood Lead Levels (BLL) were estimated by Graphite Furnace Atomic Absorption Spectrophotometer. The neurobehavioral state of the children was assessed by a population-specific scale i.e., CPMS, which evaluates for neurobehavior under 8 factors, titled, Low intelligence with behavioural problems, Conduct disorder, Anxiety, Depression, Psychotic symptoms, Special symptoms, Physical illness with emotional problems, and Somatization. The median BLL of the study population was 4.9 µg/dL. Habit of frequently consuming roadside food, proximity of residence to vehicular traffic and educational status of the mother were observed to be significant contributing factors for high BLL (≥ 5 µg/dL). Serum alkaline phosphatase (P = 0.02) and phosphorous levels (P = 0.04) were significantly lower in children belonging to high BLL group. A significantly high adverse neurobehavioral score was observed in high BLL group children compared to low BLL group (P < 0.05). There was high prevalence of Pb toxicity with 50% of children having BLL > 5 µg/dL. Further, certain lifestyle characteristics such as proximity of residence to vehicular traffic, frequent consumption of roadside food and lower educational status of the mother could be possible risk factors for higher Pb exposure in children. Evaluation of neurobehavior in children with high BLL revealed a high prevalence of adverse neurobehavior in them when compared to children in low BLL group.

Association Between Circulating Plasmacytoid Dendritic Cell Percentage and Blood Lead Levels in Children.

Lead (Pb) exposure is known to cause T helper 1 (Th1) to T helper 2 (Th2) shift in the immune response. The mechanism responsible for these effects is unclear. Plasmacytoid dendritic cells (pDCs) are known as the principal secretor of type 1 interferons (IFNs), which have a stimulatory effect on Th1 differentiation. However, no previous study has explored the effect of Pb on pDCs. Thus, the present study was conducted to explore the correlation between circulating pDC count, serum IFNα (pan) levels, and blood lead levels (BLLs) in children environmentally exposed to Pb. A total of 82 school-going children were recruited from government and private schools in Jodhpur. BLL, pDC percentages, and serum IFNα (pan) levels were estimated by atomic absorption spectrometry, flow cytometry, and ELISA, respectively, in 82 samples. The participants were divided as per BLL quartiles into 4 groups: (A) BLL < 3 µg/dL (n = 21), (B) BLL = 3-4.08 µg/dL (n = 20), (C) BLL = 4.08-6.17 µg/dL (n = 20), and (D) BLL > 6.17 µg/dL (n = 21). Only in category D, pDC percentages showed a significant positive correlation with BLL (Spearman's R = 0.5). Therefore, this preliminary data suggests that BLL might modulate pDC levels in a dose-dependent manner.