The Relationship between Blood Lead, Blood Pressure, Stroke, and Heart Attacks in Middle-Aged British Men

• Published in: Environmental health perspectives 1988-06, Vol.78, p.23-30
• Main Authors: Pocock, S. J., Shaper, A. G., Ashby, D., Delves, H. T., Clayton, B. E.
• Format: Article
• Language: English
• Subjects: Adult; Alcohol drinking; Blood; Blood pressure; Blood Pressure - drug effects; Body mass index; Cerebrovascular Disorders - epidemiology; Cerebrovascular Disorders - etiology; Cigarette smoking; Diastolic blood pressure; Health Surveys; Humans; Lead; Lead - blood; Lead - pharmacology; Male; Middle Aged; Myocardial Infarction - epidemiology; Myocardial Infarction - etiology; Pipe smoking; Strokes; Symposium on Lead-Blood Pressure Relationships. April 27-29, 1987. Chapel Hill, North Carolina; Systolic blood pressure; United Kingdom
• ISSN: 0091-6765; 1552-9924
• DOI: 10.1289/ehp.887823

The relationship between blood lead concentration and blood pressure is examined in a survey of 7371 men aged 40 to 59 from 24 British towns. After allowance for relevant confounding variables, including town of residence and alcohol consumption, there exists a very weak but statistically significant positive association between blood lead and both systolic and diastolic blood pressure. These cross-sectional data indicate that an estimated mean increase of 1.45 mm Hg in systolic blood pressure occurs for every doubling of blood lead concentration with a 95% confidence interval of 0.47 to 2.43 mm Hg. After 6 years of follow-up, 316 of these men had major ischemic heart disease, and 66 had a stroke. After allowance for the confounding effects of cigarette smoking and town of residence there is no evidence that blood lead is a risk factor for these cardiovascular events. However, as the blood lead-blood pressure association is so weak, it is unlikely that any consequent association between lead and cardiovascular disease could be demonstrated from prospective epidemiological studies. An overview of data from this and other large epidemiological surveys provides reasonably consistent evidence on lead and blood pressure. While NHANES II data on 2254 U.S. men indicate a slightly stronger association between blood lead and systolic blood pressure, data from two Welsh studies on over 2000 men did not show a statistically significant association. However, the overlapping confidence limits for all these studies suggest that there may be a weak positive statistical association whereby systolic blood pressure is increased by about 1 mm Hg for every doubling of blood lead concentration. Nevertheless, such statistical association cannot be taken as establishing a causal effect of low-level lead exposure on blood pressure, particularly since there are important confounders, e.g., alcohol consumption, which are much more strongly related to blood pressure.