Tatham Lilith M, Bove Frank J, Kaye Wendy E, Spengler Robert F
Division of Health Studies, ATSDR, Atlanta, Georgia, USA.
Int J Hyg Environ Health. 2002 Mar;205(1-2):41-8. doi: 10.1078/1438-4639-00128.
Communities surrounding the Hanford Nuclear Reservation in southeastern Washington were exposed to radionuclides, particularly iodine-131, released during the period 1945 to 1951. This study evaluated whether estimated iodine-131 exposures were risk factors for infant mortality, fetal death, and preterm birth in the years of highest releases, 1945 and 1946. Data on births, fetal deaths, and infant deaths, during the period 1940 to 1950, were abstracted from vital records for an eight county area surrounding the Hanford facility. The analysis included 56,320 births, 1,656 infant deaths, and 806 fetal deaths. The Hanford Environmental Dose Reconstruction project provided iodine-131 dose estimates for the 1,102 grid areas in the study area. The grid areas were collapsed into 4 exposure groups using estimated exposure to iodine-131 during 1945. Each birth and death record was assigned to one of the four grid groups based on mother's residence at the time of birth. Comparisons of preterm birth, infant death, and fetal death rates were made among the grid groupings for the primary exposure period (1945 to 1946) and for other years of the study period (i.e., 1940 to 1944 and 1947 to 1950). In the grid group with the highest estimated iodine-131 exposures, the mother's residence during the latter part of pregnancy was associated with preterm birth (OR = 1.74, 95% CI = 1.09-2.72). An association with infant mortality (OR = 1.26, 95% CI = 0.79-1.97) was suggested. No association was found for fetal deaths. This study found that iodine-131 exposure was associated with increased risk of preterm birth. This finding is biologically plausible because other studies have found that: (1) iodine-131 exposure can cause hypothyroidism, and (2) overt or subclinical hypothyroidism during pregnancy can increase a mother's risk of a preterm delivery.
华盛顿州东南部汉福德核保留地周边的社区在1945年至1951年期间接触到了放射性核素，尤其是碘-131。本研究评估了在释放量最高的年份（1945年和1946年），估计的碘-131暴露量是否为婴儿死亡率、胎儿死亡和早产的危险因素。1940年至1950年期间的出生、胎儿死亡和婴儿死亡数据，是从汉福德设施周边八个县的重要记录中提取的。分析包括56320例出生、1656例婴儿死亡和806例胎儿死亡。汉福德环境剂量重建项目提供了研究区域内1102个网格区域的碘-131剂量估计值。利用1945年期间估计的碘-131暴露量，将网格区域合并为4个暴露组。根据母亲在分娩时的居住地，将每份出生和死亡记录分配到四个网格组之一。对主要暴露期（1945年至1946年）和研究期的其他年份（即1940年至1944年和1947年至1950年）的网格分组之间的早产、婴儿死亡和胎儿死亡率进行了比较。在估计碘-131暴露量最高的网格组中，母亲在妊娠后期的居住地与早产有关（比值比=1.74，95%置信区间=1.09-2.72）。提示与婴儿死亡率有关（比值比=1.26，95%置信区间=0.79-1.97）。未发现与胎儿死亡有关。本研究发现碘-131暴露与早产风险增加有关。这一发现从生物学角度来看是合理的，因为其他研究发现：（1）碘-131暴露可导致甲状腺功能减退，以及（2）孕期显性或亚临床甲状腺功能减退可增加母亲早产的风险。
