Dietary and environmental determinants of blood and bone lead levels in lactating postpartum women living in Mexico City.

Abstract

Despite the recent declines in environmental lead exposure in the United States and Mexico, the potential for delayed toxicity from bone lead stores remains a significant public health concern. Some evidence indicates that mobilization of lead from bone may be markedly enhanced during the increased bone turnover of pregnancy and lactation, resulting in lead exposure to the fetus and the breast-fed infant. We conducted a cross-sectional investigation of the interrelationships between environmental, dietary, and lifestyle histories, blood lead levels, and bone lead levels among 98 recently postpartum women living in Mexico City. Lead levels in the patella (representing trabecular bone) and tibia (representing cortical bone) were measured by K X-ray fluorescence (KXRF). Multivariate linear regression models showed that significant predictors of higher blood lead included a history of preparing or storing food in lead-glazed ceramic ware, lower milk consumption, and higher levels of lead in patella bone. A 34 micrograms/g increase in patella lead (from the medians of the lowest to the highest quartiles) was associated with an increase in blood lead of 2.4 micrograms/dl. Given the measurement error associated with KXRF and the extrapolation of lead burden from a single bone site, this contribution probably represents an underestimate of the influence of trabecular bone on blood lead. Significant predictors of bone lead in multivariate models included years living in Mexico City, lower consumption of high calcium content foods, and nonuse of calcium supplements for the patella and years living in Mexico City, older age, and lower calcium intake for tibia bone. Low consumption of milk and cheese, as compared to the highest consumption category (every day), was associated with an increase in tibia bone lead of 9.7 micrograms Pb/g bone mineral. The findings of this cross-sectional study suggest that patella bone is a significant contributor to blood lead during lactation and that consumption of high calcium content foods may protect against the accumulation of lead in bone. Images Figure 1. Figure 1. Figure 2. Figure 2.

Association between essential tremor and blood lead concentration.

“…Data on current diet were collected using a semiquantitative foodfrequency questionnaire (Willett et al 1985), which included questions on frequency of consumption of 61 foods and on the use of vitamins and mineral supplements. Food frequency data may be used to compute mean daily intake of vitamins and minerals, including vitamin C, calcium, and iron (in milligrams), each of which has been associated with blood or bone lead concentrations (Cheng et al 1998;Dawson et al 1999;Hernandez-Avila et al 1996;Willett 1990). The questionnaire has shown good reliability and validity related to recent nutrient intake (Willett 1990;Willett et al 1985).…”

“…We began with an unadjusted model and then considered variables that were suspected to confound the lead-diagnosis association or were known to be associated with BPb (Cheng et al 1998;Dawson et al 1999;Hernandez-Avila et al 1996): age in years; sex; race (white vs. nonwhite); number of rooms in home; years of education; current cigarette smoker (yes vs. no); pack-years of smoking; reported daily consumptions of vitamin C, calcium, and iron; and ethanol use (heavy vs. light use). In the final model, we included a variable if in a univariate model either a) it was associated with the diagnosis (at p < 0.10) or b) it was associated with the BPb concentration (at p < 0.10).…”

Skeletal lead release during bone resorption: effect of bisphosphonate treatment in a pilot study.

“…Thus, these agents may have the additional benefit of preventing increases in BPb levels commonly seen in these life stages. During pregnancy, calcium supplementation is associated with lower BPb levels (22)(23)(24), although calcium given alone has not been proven to reverse the loss of bone mineral density during pregnancy (24) or in postmenopausal subjects (25). In menopausal women, antiresorptive agents such as hormone replacement therapy (HRT) and bisphosphonates are capable of preventing loss of bone density (20,25,26).…”

Lead Poisoning Among Pregnant Women in New York City: Risk Factors and Screening Practices

“…Among the cases described here (as in the United States as a whole), 26 the country with the single largest number of immigrants was Mexico, where high endemic levels of lead exposure in the general population and among pregnant women have been reported, 27 especially in comparison with their American counterparts. 28,29 Several women reported a history of lead exposure in their country of origin and were without current exposures. Lead can accumulate in the bone.…”