Lead Exposure and Cardiovascular Disease—A Systematic Review

Abstract

ObjectiveThis systematic review evaluates the evidence on the association between lead exposure and cardiovascular end points in human populations.MethodsWe reviewed all observational studies from database searches and citations regarding lead and cardiovascular end points.ResultsA positive association of lead exposure with blood pressure has been identified in numerous studies in different settings, including prospective studies and in relatively homogeneous socioeconomic status groups. Several studies have identified a dose–response relationship. Although the magnitude of this association is modest, it may be underestimated by measurement error. The hypertensive effects of lead have been confirmed in experimental models. Beyond hypertension, studies in general populations have identified a positive association of lead exposure with clinical cardiovascular outcomes (cardiovascular, coronary heart disease, and stroke mortality; and peripheral arterial disease), but the number of studies is small. In some studies these associations were observed at blood lead levels < 5 μg/dL.ConclusionsWe conclude that the evidence is sufficient to infer a causal relationship of lead exposure with hypertension. We conclude that the evidence is suggestive but not sufficient to infer a causal relationship of lead exposure with clinical cardiovascular outcomes. There is also suggestive but insufficient evidence to infer a causal relationship of lead exposure with heart rate variability.Public Health ImplicationsThese findings have immediate public health implications. Current occupational safety standards for blood lead must be lowered and a criterion for screening elevated lead exposure needs to be established in adults. Risk assessment and economic analyses of lead exposure impact must include the cardiovascular effects of lead. Finally, regulatory and public health interventions must be developed and implemented to further prevent and reduce lead exposure.

Lead reduces tension development and the myosin ATPase activity of the rat right ventricular myocardium

“…Although significant progress has occurred regarding environmental contamination, there are still serious problems produced by heavy metals. The positive correlation between plasma lead concentration and hypertension (6)(7)(8), one of the most prominent cardiovascular problems in many countries, and the increase of all-cause mortality, including circulatory and cancer mortality (5), reinforce the biological significance of lead as an important hazard.…”

“…In the first protocol (strip weight = 24.8 ± 1.64 mg, N = 8), concentration-response curves to increasing concentrations of lead acetate (3,7,10,30,70, 100, and 300 µM) were performed. Tests were performed at Lmax (optimum length for contraction) and peak isometric force, time to peak tension and relaxation time were measured.…”

“…Previous research reported that exposure to low levels of lead causes hypertension in animals and humans (6,7). Analyzing data from the Third National Health and Nutrition Examination Survey (NHANES, 1988(NHANES, -1994, a positive correlation was reported between plasma lead concentration and arterial pressure in black men and women (8).…”

“…To evaluate these effects, force was measured in right ventricular strips that were contracting isometrically in 45 male Wistar rats (250-300 g) before and after the addition of increasing concentrations of lead acetate (3,7,10,30, 70, 100, and 300 µM) to the bath. Changes in rate of stimulation (0.1-1.5 Hz), relative potentiation after pauses of 15, 30, and 60 s, effect of Ca 2+ concentration (0.62, 1.25, and 2.5 mM), and the effect of isoproterenol (20 ng/mL) were determined before and after the addition of 100 µM Pb 2+ .…”

Toxic effects of mercury, lead and gadolinium on vascular reactivity

“…Human beings usually have lead in their organism (8) which, upon sufficient exposure and/or accumulation in the body (32,33), can exert adverse effects. Although having no physiological function, its toxic effects on humans and animals have long been known, affecting almost all organs and systems in the human body.…”