Estimation of the pooled mean blood lead levels of Indian children: Evidence from systematic review and meta-analysis

Abstract

A recent systematic review reported very high pooled estimates of blood lead levels (BLLs) for Indian children. Current study aimed at systematically pooling the BLLs of Indian children (aged ≤ 14 years). Further, explore the time trend of BLLs with respect to implementing the ban on the use of Pb-petrol (i.e.2000) and a decade later (2010). Observational studies documenting the BLL in Indian children (aged ≤ 14 years) from PubMed-Medline, Scopus, and Embase digital databases from inception to August 2024 were systematically reviewed. Detailed protocol is available at PROSPERO (ID: CRD42022382835). Pooled mean BLL was estimated using the random-effects model and conventional-I ² statistics to assess the heterogeneity, while the Newcastle Ottawa Scale for bias assessment. Sub-group, sensitivity, and meta-regression analyses were performed where data permitted. Observations from 65 reports (51 original studies) revealed pooled BLL of 10.4 (95 % CI: 9.55-11.2) µg/dL with a trend of gradual reduction during the last 3 decades. Subgroup analysis revealed the high risk (with known Pb exposure) children had BLL of 14.3 (12.3-16.2) µg/dL, while that of the low risk (no known Pb exposure) is 8.71 (7.71-9.71) µg/dL. Only the low risk group exhibited a time trend of a gradual reduction in BLL. Notably, the review observed high heterogeneity. A progressive decline in Pb burden with respect to the national ban on leaded petrol was observed. However, present observations emphasize remedial actions toward non-occupational Pb exposure particularly among high risk Pb group, such as periodic BLL surveys.

Keywords: Environmental intervention; High risk group; Lead poisoning; Time trend analysis; Unknown exposure group.

Graphical abstract

Fig. 1

Forest plot for pooled BLLs among Indian children aged ≤ 14 years (Legends / footnotes) Forest plot demonstrates the pooled Pb levels of Indian children is 10.4 (95 % CI: 9.55–11.2) µg/dL with unacceptably high heterogeneity among the included studies (I² = 99.67 %).

Fig. 2

Forest plot of the subgroup analysis (decade) of studies reporting BLL among children with low risk / unknown Pb exposure (Legends / footnotes) Sub group analysis evaluating the influence of study publication (i.e. before 2000 vs. between 2000 and 2010 vs. after 2010) on the results.