BLOOD LEAD LEVELS IN RELATION TO MENOPAUSE, SMOKING, AND PREGNANCY HISTORY

Postmenopausal bone loss may result in the release of lead stored in b one. This study examined Mexican-American women aged 20 years and olde r who participated in the Hispanic Health and Nutrition Examination Su rvey (1982-1984) to assess the influence of menopause, pregnancy histo ry, and smoking on blood lead levels. After adjustment for factors lik ely to influence blood lead levels and for design effects, the authors confirmed associations with age, income level, education, degree of u rbanization, and body mass. Blood lead concentrations were markedly hi gher among current smokers and postmenopausal women, with these two fa ctors showing separate, roughly additive effects. Gravidity had little impact on blood lead level among premenopausal women. However, among postmenopausal women, never-pregnant women had higher blood lead level s than did those who had ever been pregnant. The largest increase (4.4 mu g/dl, 95 percent confidence interval 0.95, 7.8) was observed among smokers. In a separate analysis of postmenopausal women, women with r ecent menopause (4 years or less) had blood lead concentrations 1.4 mu g/dl higher (95 percent confidence interval 0.20, 2.7) than did those whose menopause occurred more than 4 years previously. This finding, along with an overall slow decline in blood lead levels with each year after menopause, suggests that lead is being mobilized at rates consi stent with the patterns of bone loss, placing women with recent menopa use at increased risk for higher blood lead levels.