Does low lead exposure affect blood pressure and hypertension?

Objectives Historically, little was known about the effects of low blood lead level (BLL < 10 mu g/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 mu g/dL and were selected for the study. The quartiles of peak BLL in lead-exposed workers were as follows: first (0.01-3.68 mu g/dL), second (3.69-5.19 mu g/dL), third (5.20-6.86 mu g/dL), and fourth (6.87-10.00 mu g/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 (beta 0.04, P < .01) and DBP (beta 0.06, P < .01) increased in line with a 1 mu g/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 mu g/dL was associated with HTN; thus, even in workers with low BLLs (<10 mu g/dL), management of BP is likely to be necessary. Modulation of the current safety standards for BLLs in workers will be needed.