BLOOD LEAD LEVELS IN PREGNANT-WOMEN OF HIGH AND LOW SOCIOECONOMIC-STATUS IN MEXICO-CITY

This study examined the determinants of blood lead (BPb) in 513 pregna nt women in Mexico City: 311 from public hospital prenatal clinics, re presenting primarily women of low socioeconomic status (SES), and 202 from private hospitals, primarily women of high SES. Overall, BPb leve ls ranged from 1.38 to 29 mu g/dl, with geometric means of 6.7 and 11. 12 mu g/dl for women from private and public hospitals, respectively. The crude geometric means difference obtained by t-test was 4.42 (p <0 .001). BPb was measured from January 1994 to August 1995 and showed hi gher levels during fall and winter and lower levels during spring and summer. The main BPb determinants were the use of lead-glazed ceramics in women from public hospitals and season of the year in women from p rivate hospitals. Consumption of tortillas (corn bread rich in calcium ) decreased BPb levels in the lower SES group, but the relationship wa s not statistically significant (p >0.05). Consumption of milk product s significantly (p <0.05) reduced BPb levels in the higher SES group. In 112 women whose diets were deficient in calcium, taking calcium sup plements lowered their blood lead levels about 7 mu g/dl. A predictive model fitted to these data, using the strongest predictors plus gesta tional age, showed a difference of 14 mu g/dl between the best and wor st scenarios in women from public hospitals. Avoiding use of lead-glaz ed ceramics, consuming diets rich in calcium, and, if needed, taking c alcium supplements, would be expected to result in substantial lowerin g of BPb, especially in pregnant women of low socioeconomic status.