Blood lead level and blood pressure during pregnancy in South Central Los Angeles

In many studies in which the relationship between blood pressure and blood lead level has been examined, investigators have found significant-hut smal l-associations. There was only one previous report of a significant associa tion of blood lead with blood pressure in pregnant women. We measured blood lead level and sitting blood pressure of 1 627 women in their third trimes ter of pregnancy. We eliminated subjects with known causes of hypertension. Most women (98.4%) were normotensive. We controlled for body mass index, a ge, and stress-among other factors-and constructed multiple-regression mode ls of lead association with diastolic and systolic blood pressures. Immigra nts (73% of total) bad significantly higher blood lead levels and different blood pressures than nonimmigrants, suggesting that analysis be stratified by "immigrant, nonimmigrant" status. Positive relationships between blood lead level and blood pressure were found only for immigrants (p less than o r equal to .001). From the 5th to 95th blood-lead percentiles (0.9-6.2 mu g /dl) in immigrants, systolic blood pressure increased 2.8 mm Hg, and diasto lic blood pressure increased 2.4 mm Hg, Higher prior lead exposure of immig rants (97.7% from Latin countries) than nonimmigrants might explain the dif ferential effect of these low levels of blood lead on blood pressure in non immigrants. Perhaps some immigrants are at higher risk than nonimmigrants f ar lead-associated elevated blood pressure during pregnancy, despite blood lead levels within the currently considered acceptable range.