Maternal Blood Lead Level During Pregnancy in South Central Los Angeles

Abstract

Twenty-five years of public health efforts produced a striking reduction in lead exposure; the blood lead average in the United States has decreased to less than 20% of levels measured in the 1970s. However, poor minority groups that live in large urban centers are still at high risk for elevated lead levels. In this study, our data showed that pregnant immigrants (n = 1,428) who live in South Central Los Angeles--one of the most economically depressed regions of California--have significantly higher (p < .0001) blood lead levels (geometric mean = 2.3 microg/dl [0.11 micromol/l]) than 504 pregnant nonimmigrants (geometric mean = 1.9 microg/dl [0.09 micromol/l]). The most important factors associated with lower blood lead levels in both groups were younger age; more-recent date of blood sampling (i.e., decreasing secular trend); and blood sampling in mid-autumn, instead of mid-spring (i.e., seasonal trend). Blood lead levels of immigrants were strongly dependent on time elapsed since immigration to the United States; each natural log increase in years of residence was associated with an approximately 19% decrease in blood lead levels. Although blood lead means for both groups were almost the same as the estimated national average, 25 of the 30 cases of elevated blood lead (i.e., > or = 10 microg/dl [0.48 micromol/l) occurred in the immigrant group. The odds ratio (95% confidence intervals within parentheses) for having elevated blood lead levels (a) was 9.3 (1.9, 45.8) if the immigrant engaged in pica; (b) was 3.8 (1.4, 10.5) if the immigrant had low dietary calcium intake during pregnancy; and (c) was .65 (.43, .98) for every natural log unit increase of years of residence in the United States. The control of pica and dietary calcium intake may offer a means of reducing lead exposure in immigrants.

Effect of magnitude and timing of maternal pregnancy blood lead (Pb) levels on birth outcomes

“…Characterization of these effects is important for determining appropriate clinical care for Pb-exposed women and newborns and for development of preventive public health policy, given the well-known association between poor developmental trajectories and these birth outcomes [2][3][4] and the increased prevalence of these events among poor and other at-risk populations, 5,6 who are also known to be at increased risk for Pb exposure. [7][8][9] Previous epidemiologic studies examining the association between prenatal Pb exposure, birth weight, length of gestation, and intrauterine growth have differed in their conclusions. [10][11][12][13][14][15][16] Such differences might be explained in part by under-and overcontrol of potential confounders, choices with respect to categorical versus continuous representation of predictors and outcomes, and significant differences in the range of maternal blood lead (Pb) levels (BLLs) considered.…”

Geophagia is not associated with Trichuris or hookworm transmission in Zanzibar, Tanzania

“…Proponents of pica suggest potential benefits such as mineral supplementation (especially iron and calcium), relief of gastrointestinal distress and detoxification, particularly of plant secondary compounds (Johns, 1999;Profet, 1992;Wiley and Katz, 1998). Others posit a range of harmful effects, including geohelminth infection, caloric displacement, constipation, dental damage, eclampsia, fatigue, hypertension, intestinal blockage, iron deficiency, lead poisoning, peritonitis and, most frequently, anaemia (Halsted, 1968;Key et al, 1982;Rothenberg et al, 1999;Sayetta, 1986).…”

Teratogen update: Lead and pregnancy

“…The prevalence of elevated blood lead levels is also higher among internationally adopted children . In a study of 1428 pregnant women in south central Los Angeles, of whom 74% were immigrants, mostly Latino, the number of years living in the United States was among the strongest predictors of a blood lead level exceeding 10 g/dl (Rothenberg et al, 1999b). Although a strong inverse relationship was found between blood lead level and number of years in the United States, the rate of decline was shallow, suggesting that the women arrived in the United States with substantial bone lead burdens.…”