Evaluation of an association between lead exposure and hypertension and the role of the renin-angiotensin system among occupationally exposed individuals

Background: Lead (Pb), a ubiquitous environmental toxin linked with various illnesses, including hypertension (HTN). Though preclinical models have proposed various mechanisms, few epidemiological studies explored the operative pathway(s) demonstrating HTN associated with chronic Pb exposure. The present study examined the association between occupational Pb exposure and hypertension, while also investigating the role of the renin-angiotensin system (RAS) in this association. Methods: Occupationally Pb-exposed individuals recruited in the study during their periodic medical examination. Demographic details were collected by pre-standardized semi-structured questionnaires. Blood-Pb levels (BLL) were determined using microwave-assisted acid digestion and ICP-MS. Blood pressure (BP) was measured using a pre-calibrated digital BP instrument. The role of the RAS was investigated among Pb-exposed workers (BLL >= 40 mu g/dL) with (group-1 with BP >= 140/90 mmHg) and without (group-2 with BP < 140/90 mmHg) HTN. Renin levels and angiotensin-I converting enzyme (ACE) activity were determined using the standard ELISA method. The data was analyzed using SPSS software version 24.0. Result: The study group (n = 250) observed a mean BLL of 36.79 +/- 14.79 mu g/dL, with an overall 34.80 % prevalence of HTN. The SBP (Systolic Blood Pressure) & DBP (Diastolic Blood Pressure) were significantly higher among the individuals with BLL >= 40 mu g/dL (n = 104; upper acceptable limit by OSHA) as compared to those with BLL <40 mu g/dL (n = 146). The ACE activity was significantly higher (p < 0.001) among group-1 (n = 25) as compared to group-2 (n = 25). Conclusion: The study observed an association between BLL and HTN status in occupationally exposed individuals with BLL >= 40 mu g/dL. The changes observed in RAS parameters suggest the potential involvement of RAS in the Pb-induced HTN among occupationally exposed individuals with BLL >= 40 mu g/dL.