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Blood lead as a cardiovascular risk factor
1Institute of Social Medicine, University of Copenhagen, Denmark.
Insights
This study suggests a weak causal link between lead exposure and increased blood pressure, cardiovascular disease, and mortality. While the individual impact is small, population-wide risks from lead exposure may be significant.
Area of Science:
- Environmental Health
- Cardiovascular Epidemiology
- Toxicology
Background:
- Epidemiologic and animal studies suggest a link between lead exposure and cardiovascular issues.
- Lead exposure has been hypothesized as a cause of hypertension and cardiovascular disease.
Purpose of the Study:
- To investigate the association between blood lead levels and cardiovascular health outcomes.
- To examine the relationship between changes in blood lead over time and blood pressure.
- To assess the long-term impact of blood lead on mortality and cardiovascular disease.
Main Methods:
- Longitudinal study of 1,052 men and women in Copenhagen County, Denmark, with examinations in 1976 and 1981 (men also in 1987).
- Follow-up for hospital admissions and deaths over 14 years.
- Statistical analysis controlling for confounders.
Main Results:
- Blood lead levels decreased significantly in both men and women over the study period.
- Initial univariate associations between blood lead and blood pressure were observed, but often disappeared after controlling for confounders.
- Blood lead was a significant predictor of total mortality even after adjusting for confounders.
Conclusions:
- The study supports a weak causal association between blood lead and blood pressure, total mortality, and cardiovascular disease.
- The individual health impact of lead exposure is modest, but the population attributable risk may be considerable.
- Public health efforts to reduce environmental lead exposure remain important for cardiovascular health.
Abstract:
Many epidemiologic and experimental animal studies support the hypothesis of there being a causal association between lead exposure and increased blood pressure/cardiovascular disease. This study includes 1,052 men and women from Copenhagen County, Denmark, who were examined in 1976 and 1981; in 1987, only the men were examined. Blood lead fell by approximately 40% for the men during the 11-year period and by approximately 30% for the women during the first 5-year period. There was a univariate association between systolic blood pressure and blood lead for both sexes in 1976, but it disappeared at the following examinations. For women, there was also a significant association with diastolic blood pressure, even after confounders were controlled for at the two examinations. Moreover, the authors found a significant univariate association between changes in blood lead and changes in systolic blood pressure from 1976 to 1987 in the males. All participants taking part in the study in 1976 were followed regarding hospital admissions and deaths throughout a follow-up period lasting for 14 years. There was a significant univariate association with total mortality, coronary heart disease, and cardiovascular disease. However, with regard to coronary heart disease and cardiovascular disease, the associations disappeared when confounders were controlled for. Blood lead was a significant predictor of total mortality after control for relevant confounders. This study supports the hypothesis of there being a weak causal association between blood lead and blood pressure, total mortality, coronary heart disease, and cardiovascular disease. The importance of this association is very modest for the individual, but the population attributable risk may be considerable.