交通相关毒素与儿童期肾癌有关

明尼阿波利斯——加州大学公共卫生学院的流行病学博士研究生Anshu Shrestha女士在儿科与围产期流行病学研究学会年会上报告，出生前暴露于交通相关毒素可能增加儿童期最常见肾癌——肾母细胞瘤的发病风险。并且研究结果提示，不同毒素可能在特定的妊娠阶段作用较强。

主要的交通相关毒素为甲醛、铅和六价铬，有研究显示，这些毒素均可增加成人肾癌的发病风险，但既往并不清楚其与儿童期肾癌的关系。肾母细胞瘤的发生率为1例/20万~25万名儿童，发病年龄通常为3~8岁，8岁以上发病者非常罕见。如肿瘤未发生转移，治愈率约为90%。

在这项以人群为基础的病例对照研究中，共纳入加州癌症注册数据库中的84例诊断肾母细胞瘤时年龄不超过5岁的患儿，并在出生注册数据库中随机选择25,222例出生年份匹配的对照者。病例和对照者生活在加州大气资源局监测点周围半径5英里范围内，在这一地区每12天测定一次24 h平均空气毒物水平。基于致癌性和充分的样本量选择20种空气毒素，并计算在早、中、晚妊娠期的平均暴露水平。逻辑回归分析中对出生年份、母体年龄、母体种族和社会经济状况进行了校正。

结果显示，孕晚期暴露于甲醛使肾母细胞瘤发病风险增加了接近0.5倍[比值比(OR)为1.43]。孕早期暴露于六价铬和孕中期暴露于铅也会增加肾母细胞瘤的发病风险，但程度较轻(OR分别为1.10和1.27)。孕早期暴露于铅、硒和苯与肾母细胞瘤发病风险增高相关，而与暴露于1,3-丁二烯、苯乙烯和邻二氯苯无关。

研究者还发现，接近半数(47.6%)的病例为非西班牙裔，52.4%生活于最低的两个社会经济水平，55%的患儿出生时母亲年龄为20~29岁。仅有10.7%的病例生活于最高的社会经济水平。

研究者总结认为，宫内暴露于主要交通相关毒素甲醛、铅和六价铬与出生后肾母细胞瘤发病风险增高相关，并且不同毒素在不同妊娠期的作用强度存在差异。

该研究由国立环境卫生科学研究院提供的一项基金资助。Shrestha女士未提供任何利益冲突信息。

爱思唯尔  版权所有

By: PATRICE WENDLING, Ob.Gyn. News Digital Network

MINNEAPOLIS – Prenatal exposure to traffic-related toxins may increase the risk for Wilms tumor, the most common form of childhood kidney cancer, the results of a study suggest.

Furthermore, findings suggest that different toxins may be potent at different pregnancy periods, Anshu Shrestha reported in a poster presentation at the annual meeting of the Society for Pediatric and Perinatal Epidemiologic Research.

The main culprits – formaldehyde, lead, and chromium VI – all have been shown to increase the risk of kidney cancer in adults, but little is known about their relationship to childhood renal cancers.

Wilms tumor occurs in 1 in 200,000-250,000 children, typically striking at about 3 years and rarely developing after age 8 years. The cure rate is about 90%, if the tumor has not metastasized.

The population-based, case-control study included 84 children in the California Cancer Registry who were aged 5 years and younger at the time of diagnosis with Wilms tumor, and 25,222 controls who were randomly selected from a birth registry and matched by birth year. Cases and controls lived within a 5-mile radius of a California Air Resources Board monitoring site, which measures 24-hour averages of air toxic concentrations every 12 days. Trimester-specific averages were calculated for 20 air toxins that were selected for carcinogenic property and sufficient sample size. Logistic regression analysis was adjusted for birth year, maternal age, maternal race/ethnicity and census-based socioeconomic status.

Third-trimester exposure to formaldehyde increased the risk of Wilms tumor by nearly 1.5-fold (odds ratio, 1.43), said Ms. Shrestha, an epidemiology doctoral student at the school of public health, University of California, Los Angeles.

Exposure to chromium VI in the first trimester and to lead in the second trimester also increased the odds of Wilms tumor, although to a lesser degree (OR, 1.10 and 1.27).

Positive associations were suggested for first-trimester exposure to lead, selenium, and benzene, but not for 1,3-butadiene, styrene, and ortho-dichlorobenzene.

Ms. Shrestha said that the data are preliminary and require more work to confirm that they are not due to chance alone.

Nearly half (47.6%) of the cases were Hispanic, 52.4% lived at the two lowest socioeconomic levels, and 55% had mothers aged 20-29 years at the time of their birth. Only 10.7% of cases lived at the highest socioeconomic level (defined by a combination of seven census indicators, including education and median household income).

The study was supported by grants from the National Institute of Environmental Health Sciences. Ms. Shrestha did not provide conflict of interest information.