Population-based study of environmental lead exposure and hearing loss: a systematic review and meta-analysis

Multiple studies suggest that there is an association between environmental lead exposure and hearing loss. However, the results of studies exploring the relationship between lead exposure and the occurrence of hearing loss are inconsistent. To clarify this issue, we conducted a meta-analysis to determine the association between lead exposure and hearing loss.

This study was a meta-analysis.

A comprehensive literature search was performed using PubMed, Web of Knowledge, Elsevier ScienceDirect, and Springer databases. Eight articles involving 10 studies were included, and a random effect model was used for the meta-analysis. The Agency for Healthcare Research and Quality was used for judging the quality of the articles.

Environmental lead exposure was significantly and substantially associated with hearing loss (combined odds ratio [OR] 1.42; 95% confidence interval [CI] 1.22-1.67) with mild heterogeneity (I² = 47.0%, P = 0.049). Subgroup and sensitivity analyses confirmed the results; however, publication bias was evident. After the 'fill and trim' method, the recalculated OR was 1.36 (95% CI 1.12-1.64).

The results of this study suggest an association between lead exposure and hearing loss. Exposure to a high concentration of lead was positively proportional to the risk of hearing loss. To eliminate the effects of other confounding factors, larger prospective cohort studies are required to further elucidate the relationship between lead exposure and hearing loss.