Assessment of thyroid function in male workers of battery recycling factory occupationally exposed to lead

The association of long-term exposure to inorganic lead with harmful effects on thyroid function has not been well studied yet. During the present cross-sectional study, the authors investigated 195 male workers in a battery recycling factory in Iran. Thyroid function parameters were evaluated in relation to Blood Lead Level (BLL) and chelatable lead then compared in two subgroups of blood lead level based on Occupational Safety and Health Administration (OSHA) standards(<40 and g40 íg dL-1) and two subgroup of chelatable lead. Mean of BLL in study subjects was 43.44 íg dL-1 (14.2-85.6). No correlation between blood lead level and chelatable lead was found with thyroid indexes. There was no statistically significant difference in thyroid indexes between workers with BLL<40 and workers with BLL g 40. Similarly, no statistically significant difference was seen in thyroid indexes between workers with chelatable lead g705 íg dL-1 and workers with chelatable lead >705 íg dL-1. No evidence of linear correlation between blood lead level, chelatable lead and thyroid function parameters was observed after adjustment for potential confounders (age, BMI, cigarette smoking, duration of exposure). The authors concluded that in contrast to some studies with evidence of thyroid dysfunction in occupational lead exposure, this study showed no thyroid dysfunction in different levels of blood lead level up to 85 íg dL-1.