Does low lead exposure affect blood pressure and hypertension?

OBJECTIVES: Historically, little was known about the effects of low blood lead level (BLL < 10 μg/dL) on hypertension (HTN). The purpose of this study was to assess the effects of low BLL on blood pressure (BP) and HTN in lead‐exposed male workers in the Republic of Korea. METHODS: From the year 2000 to 2004, 12,060 male workers underwent an Annual Specialised Medical Check‐up for lead; 7,341 subjects had a peak BLL < 10 μg/dL and were selected for the study. The quartiles of peak BLL in lead‐exposed workers were as follows: first (0.01‐3.68 μg/dL), second (3.69‐5.19 μg/dL), third (5.20‐6.86 μg/dL), and fourth (6.87‐10.00 μg/dL). To examine the relationship between BLL and pre‐HTN (systolic BP [SBP] ≥120‐140 mmHg; diastolic BP [DBP] ≥80‐90 mmHg) and between BLL and HTN (SBP ≥ 140 mmHg; DBP ≥ 90 mmHg), the quartiles of BLL were used as independent variables in multiple logistic regression analysis. RESULTS: In multiple linear regression analyses, SBP (β 0.04, P < .01) and DBP (β 0.06, P < .01) increased in line with a 1 μg/dL increase in BLL. The odds ratio (OR) of HTN in the fourth versus first BLL quartile (1.54; 95% confidence interval [CI]: 1.26, 1.89) was statistically significant. CONCLUSION: SBP and DBP were statistically significantly associated with peak BLL. A BLL ≥ 6.87 μg/dL was associated with HTN; thus, even in workers with low BLLs (<10 μg/dL), management of BP is likely to be necessary. Modulation of the current safety standards for BLLs in workers will be needed.