Residential Exposure to Polychlorinated Biphenyls and Organochlorine Pesticides and Risk of Childhood Leukemia

Background

Incidence of childhood leukemia in industrialized countries rose significantly during 1975–2004, and the reasons for the increase are not understood.

Objectives

We used carpet dust as an exposure indicator to examine the risk of childhood leukemia in relation to residential exposure to persistent organochlorine chemicals: six polychlorinated biphenyl (PCB) congeners and the pesticides α- and γ-chlordane, p,p′-DDT (dichlorodiphenyltrichloroethane), p,p′-DDE (dichlorodiphenyldichloroethylene), methoxychlor, and pentachlorophenol.

Methods

We conducted a population-based case–control study in 35 counties in northern and central California in 2001–2006. The study included 184 acute lymphocytic leukemia (ALL) cases 0–7 years of age and 212 birth certificate controls matched to cases by birth date, sex, race, and Hispanic ethnicity. We collected carpet dust samples from the room where the child spent the most time before diagnosis (similar date for controls) using a specialized vacuum.

Results

Detection of any PCB congener in the dust conferred a 2-fold increased risk of ALL [odds ratio (OR) = 1.97; 95% confidence interval (CI), 1.22–3.17]. Compared with those in the lowest quartile of total PCBs, the highest quartile was associated with about a 3-fold risk (OR = 2.78; 95% CI, 1.41–5.48), and the positive trend was significant (p = 0.017). Significant positive trends in ALL risk were apparent with increasing concentrations of PCB congeners 118, 138, and 153. We observed no significant positive associations for chlordane, DDT, DDE, methoxychlor, or pentachlorophenol. The associations with PCBs were stronger among non-Hispanic whites than among Hispanics despite similar distributions of PCB levels among controls in each racial/ethnic group.

Conclusions

Our findings suggest that PCBs, which are considered probable human carcinogens and cause perturbations of the immune system, may represent a previously unrecognized risk factor for childhood leukemia.     

Polycyclic Aromatic Hydrocarbons in Residential Dust: Sources of Variability

Background: There is interest in using residential dust to estimate human exposure to environmental contaminants.Objectives: We aimed to characterize the sources of variability for polycyclic aromatic hydrocarbons (PAHs) in residential dust and provide guidance for investigators who plan to use residential dust to assess exposure to PAHs.Methods: We collected repeat dust samples from 293 households in the Northern California Childhood Leukemia Study during two sampling rounds (from 2001 through 2007 and during 2010) using household vacuum cleaners, and measured 12 PAHs using gas chromatography–mass spectrometry. We used a random- and a mixed-effects model for each PAH to apportion observed variance into four components and to identify sources of variability.Results: Median concentrations for individual PAHs ranged from 10 to 190 ng/g of dust. For each PAH, total variance was apportioned into regional variability (1–9%), intraregional between-household variability (24–48%), within-household variability over time (41–57%), and within-sample analytical variability (2–33%). Regional differences in PAH dust levels were associated with estimated ambient air concentrations of PAH. Intraregional differences between households were associated with the residential construction date and the smoking habits of residents. For some PAHs, a decreasing time trend explained a modest fraction of the within-household variability; however, most of the within-household variability was unaccounted for by our mixed-effects models. Within-household differences between sampling rounds were largest when the interval between dust sample collections was at least 6 years in duration.Conclusions: Our findings indicate that it may be feasible to use residential dust for retrospective assessment of PAH exposures in studies of health effects.     

月经和生育因素对妇女肺癌危险度的影响

目的 验证雌激素可能对肺癌危险度产生的影响 方法 1994～1998年在甘肃省陇东地区进行了一项女性人群的病例对照研究,分析了月经和生育因素与肺癌危险度之间的关系。病例组为109例女性肺癌病例和435名女性为对照组,对照组是根据人口调查资料,按年龄和地区与病例频数匹配得到的。结果 初潮年龄晚(趋势检验P=0.015)、绝经年龄晚(趋势检验P=0.074)的女性,其肺癌比值比较低。结论 尽管有局限性,上述发现表明雌激素在女性肺癌病因学中起到一定作用。     

Genetic variants in ARID5B and CEBPE are childhood ALL susceptibility loci in Hispanics

Recent genome-wide studies conducted in European Whites have identified novel susceptibility genes for childhood acute lymphoblastic leukemia (ALL). We sought to examine whether these loci are susceptibility genes among Hispanics, whose reported incidence of childhood ALL is the highest of all ethnic groups in California, and whether their effects differ between Hispanics and non-Hispanic Whites (NHWs). We genotyped 13 variants in these genes among 706 Hispanic (300 cases, 406 controls) and 594 NHW (225 cases, 369 controls) participants in a matched population-based case–control study in California. We found significant associations for the five studied ARID5B variants in both Hispanics (p values of 1.0 × 10^?9 to 0.004) and NHWs (p values of 2.2 × 10^?6 to 0.018). Risk estimates were in the same direction in both groups (ORs of 1.53–1.99 and 1.37–1.84, respectively) and strengthened when restricted to B-cell precursor high-hyperdiploid ALL (>50 chromosomes; ORs of 2.21–3.22 and 1.67–2.71, respectively). Similar results were observed for the single CEBPE variant. Hispanics and NHWs exhibited different susceptibility loci at CDKN2A. Although IKZF1 loci showed significant susceptibility effects among NHWs (p < 1 × 10^?5), their effects among Hispanics were in the same direction but nonsignificant, despite similar minor allele frequencies. Future studies should examine whether the observed effects vary by environmental, immunological, or lifestyle factors.     

Immigrating to the US: What Brazilian, Latin American and Haitian Women Have to Say About Changes to Their Lifestyle That May be Associated with Obesity

Our goal was to explore the perceived determinants of obesity in Brazilian, Latin American and Haitian women. This is part of an ongoing community-based participatory intervention. Focus groups by immigrant group were conducted and themes extracted. Women expressed differences in beliefs, attitudes, and barriers regarding diet and physical activity in the US versus their home country. Participants thought food in the US is “less natural,” there is less time for preparation, and there is more variety. The weather is a barrier to physical activity in the US and work is more physically demanding. Job-related efforts were not considered physical activity. They reported higher levels of stress, less control of their time and less social support in the US. Providing immigrants with appropriate support and education early in the acculturation process has the potential to help prevent obesity.     

Metastases of a gastric adenocarcinoma presenting as colonic polyposis

The authors report a case of multiple colonic metastases of a gastric signet ring cell adenocarcinoma, presenting as colonic polyposis revealed by diarrhea, iron deficiency anemia, and left supraclavicular lymph node.