Gulson B L, Mahaffey K R, Jameson C W, Mizon K J, Korsch M J, Cameron M A, Eisman J A
Graduate School of the Environment and CSIRO Division of Mathematics and Statistics, Macquarie University, Sydney, NSW, Australia.
J Lab Clin Med. 1998 Apr;131(4):324-9. doi: 10.1016/s0022-2143(98)90182-2.
A cohort of 15 immigrant females to Australia and 7 native Australian controls were monitored on a monthly basis with high-precision lead isotopic methods during gestation and for 6 months after pregnancy to determine the extent of lead mobilization from the maternal skeleton. Quarterly environmental samples of house dust, drinking water, urban air, gasoline, and a 6-day duplicate diet were also measured. The geometric mean blood lead concentration for the immigrant females on arrival in Australia was 3.0 microg/dl (range: 1.9 to 20 microg/dl), and for the Australian controls was 3.1 gm/dl (range: 1.9 to 4.3 microg/dl). During gestation and after pregnancy, blood lead concentrations varied, with mean individual changes of -14% to 83%. For the immigrant subjects, the percentage change in blood lead concentration was significantly greater during the postpregnancy period than during the 2nd and 3rd trimesters (p < 0.001). Skeletal contribution to blood lead, based on the isotopic composition for the immigrant subjects, increased in an approximately linear manner during pregnancy. The mean increases for each individual during pregnancy varied from 26% to 99%. Skeletal lead contribution to blood lead was significantly greater (p < 0.001) during the postpregnancy period than during the 2nd and 3rd trimesters. The contribution of skeletal lead to blood lead during the postpregnancy period remained essentially constant at the increased level of lead mobilization, although the duration of breastfeeding varied from 1 week to more than 6 months. The increased contribution of skeletal lead to blood lead during the postpregnancy period is attributed to increased mobilization of lead from maternal skeletal stores during lactation. The increased contribution of skeletal lead both during pregnancy and in the postpregnancy period is consistent with increased bone resorption, and may be associated with an inadequate calcium intake observed in quarterly 6-day duplicate diets. Mobilization of skeletal lead stores represents a potentially important source of perinatal lead intake and accumulation in the developing fetus. Only two subjects consumed dietary supplements for calcium, and their mobilization of lead from the skeleton to the blood was the lowest of all the subjects. These two subjects' use of calcium supplements may have reduced mobilization of skeletal mineral stores to supply the calcium needs of pregnancy and lactation. Calcium supplementation may be an important means of limiting fetal exposure to lead.
对15名移民到澳大利亚的女性和7名澳大利亚本地对照女性进行了队列研究，在她们孕期及产后6个月期间，每月采用高精度铅同位素方法进行监测，以确定母体骨骼中铅的动员程度。同时还对房屋灰尘、饮用水、城市空气、汽油以及为期6天的重复饮食等环境样本进行了季度测量。移民女性抵达澳大利亚时的几何平均血铅浓度为3.0微克/分升（范围：1.9至20微克/分升），澳大利亚对照女性为3.1微克/分升（范围：1.9至4.3微克/分升）。在孕期和产后，血铅浓度有所变化，个体平均变化范围为-14%至83%。对于移民受试者，产后血铅浓度的百分比变化显著大于孕中期和孕晚期（p<0.001）。根据移民受试者的同位素组成，孕期骨骼对血铅的贡献大致呈线性增加。每个个体在孕期的平均增加幅度从26%到99%不等。产后骨骼铅对血铅的贡献显著大于孕中期和孕晚期（p<0.001）。尽管母乳喂养时间从1周到超过6个月不等，但产后骨骼铅对血铅的贡献在铅动员增加的水平上基本保持恒定。产后骨骼铅对血铅贡献增加归因于哺乳期母体骨骼储存中铅的动员增加。孕期和产后骨骼铅贡献增加与骨吸收增加一致，可能与季度6天重复饮食中观察到的钙摄入不足有关。骨骼铅储存的动员是发育中胎儿围产期铅摄入和积累的一个潜在重要来源。只有两名受试者服用了钙补充剂，她们骨骼中铅向血液的动员在所有受试者中是最低的。这两名受试者使用钙补充剂可能减少了骨骼矿物质储存的动员，以满足孕期和哺乳期对钙的需求。补充钙可能是限制胎儿铅暴露的一个重要手段。
