Lead, blood pressure, and cardiovascular disease in men and women.

Abstract

Lead has been shown to be associated with elevated blood pressure in males in the NHANES II survey and in numerous other studies. This study confirms the association in males aged 20 to 74 and documents a significant, although weaker, association in females as well. Prospective cardiovascular disease studies such as the Framingham study indicate that increases in blood pressure should be associated with increased risk of cardiovascular disease. Using electrocardiogram data from NHANES II, this study confirms the expected association of lead with left ventricular hypertrophy (p < 0.01). Such an association with permanent cardiovascular changes adds weight to the blood pressure findings. The logistic risk coefficients from the Framingham study can be combined with the study's association between lead and blood pressure to examine its implication for more serious outcomes. The results suggest that a halving of the population mean blood lead level would reduce myocardial infarctions by approximately 24,000 events per year and incidence of all cardiovascular disease by over 100,000. These numbers suggest a small attributable risk compared to the vast incidence of cardiovascular disease in the U.S., but a large attributable risk compared to most environmental toxins. Several biological mechanisms have been identified, with different implications for the use of bone lead as an exposure measure.

Lead effect on blood pressure in moderately lead‐exposed male workers

“…This may explain why blood pressure effect was not identified in some studies of Pb-exposed workers, particularly if a reference group had relatively high BPb levels, which is the case in the present study. Furthermore, the group of Pb workers had significantly lower BMI and relatively high smoking intensity (the number of cigarettes per day) as compared to the reference group (Table I), each of which was previously reported to decrease human blood pressure [Tyroler, 1988;Schwartz, 1991;Menditto et al, 1994;Telišman et al, 2001]. No significant association was found between current BPb and blood pressure levels in the group of Pb workers (Tables II and III).…”

“…For example, an inverse association between blood pressure and SZn levels [Thind and Fischer, 1974;Harlan, 1988;Arora et al, 1989;Morvai, 1996;Bergomi et al, 1997], and a positive association between blood pressure and SCu levels [Morvai, 1996;Bergomi et al, 1997] was reported in subjects with no occupational exposure to metals. An independent effect of both increasing BPb and decreasing SZn to an increase in diastolic blood pressure was reported in males and in females [Schwartz, 1991]. The present study evaluates possible influence factors of BMI, Hct, age, smoking habits, and alcohol consumption on blood pressure, bearing in mind that they commonly correlate with biomarkers of Pb, Cd, Zn, or Cu in humans.…”

Mortality and cancer incidence among secondary lead smelter workers.

“…29 Thus, a lead effect on blood pressure may contribute to the increased mortality from cerebrovascular deaths reported in some studies,20 21 23 27 and possibly also to other cardiovascular deaths. 29 In accordance with this theory, the mortality from ischaemic heart diseases was raised in the present cohort. The SMR did not increase with increasing lead dose or when a latency period of 10 or 15 years was applied.…”

Cumulative lead exposure and age-related hearing loss: The VA Normative Aging Study

“…Epidemiologic studies of occupationally exposed workers have shown associations of lead exposure with hearing loss and impaired hearing ability (Chuang et al, 2007; Counter et al, 2002; Discalzi et al, 1993; Discalzi et al, 1992; Forst et al, 1997; Hwang et al, 2009; Wu et al, 2000). Studies of children have also demonstrated associations with hearing impairment (Schwartz, 1991; Schwartz et al, 1987). No study of lead and age-related hearing loss has been conducted in the general adult population, however, and it is not clear whether chronic, nonoccupational, low-level exposure to lead contributes to the development of hearing loss among older populations.…”