有机氯农药、CYP1A1易感基因型与乳腺癌的交互作用研究

[目的]分析血清有机氯农药水平与雌激素代谢基因CYP1A1易感基因型对乳腺癌患病风险的联合作用.[方法]采用成组病例对照研究方法,序贯收集乳腺癌确诊病例共102名,健康社区女性对照154名.采用气相色谱-电子捕获的方法(GC-ECD)检测血清中β-HCH,p,p'-DDT,和p,p'-DDE水平.用限制性内切酶PCR法(RFLPPCR)法检测CYP1A1基因型的m1突变型.采用logistic回归模型分析CYP1A1突变基因型对乳腺癌患病风险的相对危险度(OR),并计算交互作用系数γ.[结果]总病例对照中,CYP1A1 m1突变纯合型(v/v)的调整OR=3.26, 95%C.I.为1.12～9.53.携带CYP1A1 m1突变等位基因(wv vv)与有机氯农药(p,p'-DDT,β-HCH)高暴露的交互作用系数γ分别为8.86和8.47;绝经前女性中,上述交互作用系数γ分别为2.94和1.42.[结论]DDT及HCH可能是乳腺癌的危险因素,雌激素代谢相关的酶在其中起到协同促癌作用.     

吉林市汉族妇女GSTM1基因和CYP1A1基因Exon7位点多态性与 子宫内膜异位症易感性的研究

目的:探讨在吉林地区汉族妇女中细胞色素P450(CYP1A1)基因Exon7位点多态性即Ile-Val位点的多态性及GSTM1基因多态性和子宫内膜异位症易感性的相关关系。方法:以病例对照的研究方法,采用PCR技术检测216例子宫内膜异位症和216例对照人群的CYP1A1基因Ile-Val位点及GSTM1基因多态性的表达。结果:吉林地区汉族人群中GSTM1空白基因型分布频率0.463,内异症人群中空白基因型分布频率0.667,两组差异有统计学意义(P<0.05),空白基因型患内异症的危险是功能基因型的1.896倍;Ile-Val三种多态基因型在内异症组和对照组分布差异有统计学意义(P<0.05),Ile/Val、Val/Val基因型患内异症的危险分别是Ile/Ile基因型的1.901倍和3.056倍;CYP1A1 Ile/Val联合GSTM1空白基因型个体的OR值为3.409(95%C I 1.897~6.125,P<0.01),而CYP1A1Val/Val联合GSTM1空白基因型个体的OR值增高至7.143(95%C I 2.584~19.742,P<0.01)。结论:CYP1A1 Exon7的Ile/Val、Val/Val基因型及GSTM1空白基因型与内异症的易感性有关,二者联合效应具有协同作用,可望作为内异症易感人群筛选的重要指标。     

CYP1A1 Ile462Val多态与小细胞肺癌遗传易感性相关

目的探讨细胞色素P450 1A1(CYP1A1)基因Ile462Val单核苷酸多态与小细胞肺癌遗传易感性的相关关系。方法收集275例小细胞肺癌患者和406例正常对照者的外周静脉血标本,采用聚合酶链反应-限制性片断长度多态性分析(PCRRFLP)技术检测CYP1A1基因Ile462Val多态的基因型。采用多变量Logistic回归方法分析不同基因型与小细胞肺癌发病风险的相关关系。结果与CYP1A1 462 Ile/Ile基因型携带者相比,462 Ile/Val和462 Val/Val基因型携带者小细胞肺癌发病风险显著降低,其OR值分别为0.65(95%CI 0.48~0.91)和0.60(95%CI 0.32~0.97)。吸烟分层分析显示,在不吸烟人群中,462 Ile/Val或462 Val/Val基因型携带者小细胞肺癌发病风险的OR值为0.99(95%CI 0.62~1.51)。在吸烟人群中,462Ile/Val或462 Val/Val基因型携带者小细胞肺癌发病风险的OR值为0.42(95%CI0.26~0.65)。此外,在轻度吸烟者和重度吸烟者中462 Ile/Val或462 Val/Val基因型携带者小细胞肺癌发病风险的OR值分别为0.42(95%CI 0.21~0.85)和0.44(95%CI 0.24~0.82)。结论 CYP1A1基因Ile462Val多态与小细胞肺癌遗传易感性相关。     

细胞色素P4501A1基因多态性与食管癌易感性关系的Meta分析

目的 探讨细胞色素P4501A1(CYP1A1)MspI和Ile/Val位点基因多态性与食管癌发生的关系.方法 采用Meta分析方法,对国内外1997-2008年采用病例对照方法研究CYP1A1MspI和Ile/Val基因多态性与食管癌发生关系的16篇(MspI 8篇,Ile/Val 14篇)文献,采用显性模型(即突变基因型与野生型比较)进行综合定量分析,然后按病理分型(鳞癌/腺癌)分亚组进行分析.结果 综合分析CYP1A1 MspI突变基因型(TC+CC)与食管癌发生无统计学关联(OR=1.17,95%CI:0.82～1.66),亚组分析亦未发现CYP1A1 MspI突变基因型与食管鳞癌(OR=1.17,95%CI:0.82～1.69)和食管腺癌(OR=1.39,95%CI:0.67～2.09)的统计学关联;携带CYP1A1突变基因型(Ile/Val+Val/Val)的个体发生食管癌的危险性是野生型的1.39倍(OR=1.39,95%CI:1.07～1.80);亚组分析显示突变基因型与食管鳞癌发生的易感性相关但与食管腺癌无关联,OR值分别为1.43(95%CI:1.07～1.91)和1.20(95%CI:0.62～2.30).结论 CYP1A1 Ile/Val位点突变基因型可增加食管鳞癌发生的危险性,CYP1A1 MspI位点基因多态性与食管癌无关联.     

CYP1A1及GSTP1基因多态性与肺癌易感性关系

目的 探讨细胞色素P4501 A1(CYP1A1) Exon7和谷胱甘肽硫转移酶P1(GSTPI) Ile105 Val基因多态性与内蒙古地区汉族人群肺癌易感性关系.方法 采用等位基因特异性扩增法分析216例汉族对照人群和116例肺癌患者CYP1A1 Exon7和GSTP1 Ile105 Val基因多态性.结果 携带CYP1A1 Exon7突变杂合型和纯合型的个体患肺癌的危险均升高(OR值分别为1.460和1.593),而携带GSTP1 Ile105 Val突变杂合型和纯合型的个体患肺癌的风险均降低(OR值分别为0.970和0.602);CYP1 A1 Exon7和GSTP1 Ile105 Val基因在肺癌易感性方面无协同作用;CYP1A1 Exon7与吸烟有协同作用(OR=2.637,95％ CI=1.056～6.530,P=0.032),GSTP1 Ile105Val与吸烟无协同作用.结论 CYP1 A1 Exon7突变基因型为肺癌的可疑易感因素,CYP1A1 Exon7突变基因型和吸烟对肺癌易感有协同作用,GSTP1 Ile105Val突变基因型可降低肺癌易感性.     

CYP1A1基因多态性与吉林籍汉族女性子宫内膜异位症易感性的研究

目的:探讨在吉林市汉族妇女中CYP1A1基因Exon7位点即Ile-Val位点的多态性与子宫内膜异位症易感性的相关关系。方法:以病例对照的研究方法,采用PCR技术检测在216例子宫内膜异位症患者和216例对照人群中CYP1A1基因Ile-Val位点多态性的表达。结果:Ile-Val 3种多态基因型在病例组和对照组分布有统计学意义(P<0.05),Ile/Val、Val/Val基因型在病例组的分布频率明显高于对照组(P<0.05);Ile/Val、Val/Val基因型患子宫内膜异位症的危险分别是Ile/Ile基因型的1.901倍和3.056倍。结论:CYP1A1Exon7的Ile/Val、Val/Val基因型与子宫内膜异位症的易感性有关,可望作为子宫内膜异位症易感人群筛选的重要指标。     

CYP1A1基因多态性与肺癌个体易感性研究

[目的 ]探讨CYP1A1Msp1和Ile/Val多态性单独或联合作用 ,对肺癌易感性的影响。 [方法 ]以病例一对照研究的方法 ,采用PCR扩增限制酶切法 (PCR -RFLP)和等位基因特异性扩增 (Allele SpecificAmplification ,ASA)检测 92例肺癌病人 (病例组 )和 98例非肿瘤病人 (对照组 )CYP1A1基因Msp1和Ile/Val基因型。 [结果 ]Msp1多态性位点 :具有B和C基因型者患肺癌的危险性是A基因型者的 1 85倍 (χ2 =4 3 6,P <0 0 5 ,OR =1 85 ,95 %CI 1 0 4～ 3 3 0 )。Ile/Val多态性位点 :Val/Val基因型者患肺癌的危险性是Ile/Ile基因型者的 3 3倍 (χ2 =4 12 ,P <0 0 5 ,OR =3 3 ,95 %CI 1 0 2～10 72 )。Ile/Val基因型联合B基因型、C基因型或Val/Val基因型联合C基因型与Ile/Ile基因型联合A基因型相比 ,患肺癌的危险性增加 ,其相对危险度分别为 3 0 9(χ2 =5 81,P <0 0 5 ,95 %CI 1 7～ 9 96) ;4 74(χ2 =4 74,P <0 0 5 ,95 %CI1 11～ 2 0 9) ;5 5 (χ2 =4 42 ,P <0 0 5 ,95 %CI 1 2 7～ 2 3 6)。 [结论 ]CYP1A1基因的B、C和Val/Val基因型可能是肺癌的易感基因型 ,两种易感基因型同时存在 ,更增加对肺癌的易感性     

GSTT1及CYP1A1基因多态性与肺癌易感性关系

目的 探讨细胞色素P4501A1(CYP1A1)和谷胱甘肽硫转移酶T1(GSTT1)基因多态性与肺癌易感性的关系.方法 用等位特异性PCR(AS-PCR)及多重PCR技术分析106例肺癌患者和250名健康人的CYP1A1、GSTT1基因多态性、基因型分布频率和交互作用.结果 携带CYP1A1(Val/Val)/GSTT1(-)基因型的人患肺癌的风险明显增加(P=0.025);吸烟与肺癌易感性有关(P=0.037),吸烟者患肺癌的风险明显增加(OR=1.628.95%CI=1.028～2.577);携带CYP1A1(Val/Val)基因的吸烟者较携带CYP1A1(Ile/Ile)基因型的不吸烟者易患肺癌(P=0.033);携带GSTT1(-)的吸烟者患肺癌的风险明显增加(P=0.045).结论 CYP1A1突变型和GSTT1(-)基因型是肺癌的可疑易患因素,二者对肺癌的发生有协同作用,但单独携带CYP1A1突变型或GSTT1(-)基因型肺癌易感性差异无统计学意义,吸烟与肺癌易感性有关;CYP1A1突变型、GSTT1(-)基因型与吸烟在肺癌的发生上有相互促进作用.     

有机氯农药非职业暴露与乳腺癌患病风险的病例-对照研究

目的研究有机氯农药二氯二苯三氯乙烷(DDT)和六氯环乙烷(HCH)类雌激素污染物在非职业暴露人群的内暴露水平及与乳腺癌患病风险的关系。方法采用成组病例对照研究方法,调查90名乳腺癌新确诊患者和136名社区健康女性对照。采用问卷调查表收集病例及对照的乳腺癌相关危险因素信息。采用气相色谱-电子捕获(GC-ECD)方法检测血清中有机氯农药残留物水平。运用logistic回归模型分析8种有机氯农药残留物的血清水平与乳腺癌患病风险的相对危险度(OR)。结果病例和对照血清中均能检出p,p’-DDT、p,p’-DDE、o,p’-DDT、p,p’-DDD以及α、β、γ、δ-HCHs有机氯农药残留物,其中β-HCH、p,p’-DDE及p,p’-DDT的总检出率为91·2%、92·1%和91·2%;各物质检出水平在乳腺癌组和对照组间差异无显著性(P>0·05);控制了混杂因素后,p,p’-DDT、p,p’-DDD及δ-HCH暴露与总乳腺癌患病呈正相关(OR>2,P<0·05)。分层分析中绝经前女性的p,p’-DDT、p,p’-DDD、β-HCH血清水平与乳腺癌呈正相关,调整OR分别为3·59、5·70和3·06(P<0·05)。结论有机氯农药残留物(DDTs和HCHs)可能增加妇女,尤其在绝经前妇女患乳腺癌的风险。     

铀矿工GSTP1基因多态与MGMT基因和p16基因甲基化的关系

目的探讨氡职业暴露人群谷胱甘肽S-转移酶P1(GSTP1)基因多态与痰细胞6-氧-甲基嘌呤-DNA甲基转移酶(MGMT)和p16基因甲基化的关系。方法用聚合酶链反应-限制性片段长度多态性法(PCR-RFLP)确定70例氡职业暴露人群GSTP1的基因型;用聚合酶链反应-甲基化特异性法(MSP)确定痰细胞中MGMT和p16基因的甲基化与非甲基化状态。结果在70名铀矿工中,GSTP1基因A105G位点的纯合子(Ile/Ile)42例,杂合子(Ile/Val)25例和纯合子(Val/Val)3例。MGMT、p16基因甲基化率和总甲基化率分别为14.2%、8.6%和18.6%。与携带Ile/Ile人群相比,携带异常等位基因(Ile/Val与Val/Val)的人群MGMT基因甲基化和总甲基化率增加[P=0.037,OR=4.8,95%CI(1.1~21.0);P=0.016,OR=5.1,95%CI(1.4~19.6)];p16基因甲基化率差异无统计学意义[P=0.057,OR=4.6,95%CI(0.8~29.2)]。结论GSTP1(A105G)基因多态性与氡致MGMT基因甲基化和总甲基化的易感性有关。     

Serum polychlorinated biphenyls, cytochrome P-450 1A1 polymorphisms, and risk of breast cancer in Connecticut women

Recent epidemiologic studies have suggested that genetic polymorphisms in the cytochrome P-450 1A1 gene (CYP1A1) may affect the relation between environmental exposure to polychlorinated biphenyls (PCBs) and breast cancer risk. The authors report results from a case-control study evaluating the potential effect of gene-environment interaction between CYP1A1 and serum PCB levels on breast cancer risk among Caucasian women in Connecticut. The study included 374 case women with histologically confirmed breast cancer and 406 noncancerous controls with information on both serum PCB level and CYP1A1 genotype (1999-2002). Compared with women who had the homozygous wild-type CYP1A1 m2 genotype, significantly increased risks of breast cancer were found for women with the CYP1A1 m2 variant genotype (odds ratio (OR) = 2.1, 95% confidence interval (CI): 1.1, 3.9), especially postmenopausal women (OR = 2.4, 95% CI: 1.1, 5.0). Risks associated with the CYP1A1 m2 variant genotype were highest for all women (OR = 3.6, 95% CI: 1.5, 8.2) and postmenopausal women (OR = 4.3, 95% CI: 1.6, 12.0) with higher serum PCB levels (611-2,600 ng/g). The CYP1A1 m1 and m4 genotypes were not associated with breast cancer risk independently or in combination with PCB exposure. In summary, the CYP1A1 m2 genetic polymorphism was associated with increased risk of female breast cancer and may modify the relation between PCB exposure and breast cancer risk.     

Serum DDT and DDE levels in pregnant women of Chiapas, Mexico

The authors measured the main ingredients of technical DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl [p,p'-DDT]) and its principal metabolite, 1,1-dichloro-2,2-bis (p-chlorophenyl)ethylene [p,p'-DDE]) in serum collected from 52 pregnant women in Tapachula, Chiapas, Mexico in 1998. The median lipid-adjusted serum levels for the women were 676 ng/g p,p'-DDT (range: 56-23,169 ng/g) and 4,843 ng/g p,p'-DDE (range: 113-41,964 ng/g). In regression analysis, serum DDT and DDE increased with age (test for trend, p = .022) but decreased with total lactation (test for trend, p < .001). Residence in a house that had ever been sprayed for malaria control was also related to serum DDT and DDE. This study provides evidence of high-level exposure to DDT and DDE among pregnant women living in Chiapas, Mexico, despite countrywide restrictions on its use at the time.     

Breast cancer, lactation history, and serum organochlorines

The authors analyzed the relation between lactation history, organochlorine serum levels-in particular, 2,2-bis(p-chlorophenyl)-1,1,1-trichloroethane (DDT) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE)-and the risk of breast cancer within a subsampe from a larger breast cancer case-control study conducted among women living in Mexico City, Mexico, between 1990 and 1995. From the original study, they selected a random sample of 260 subjects (1:1 case/control ratio). Analysis was restricted to 120 cases and 126 controls who had given birth to at least one child and had complete information on all key variables. Serum DDE levels were higher among cases (mean = 3.84 microg/g lipids, standard deviation = 5.98) than among controls (mean = 2.51 microg/g lipids, standard deviation = 1.97). After adjustment for age, age at menarche, duration of lactation, Quetelet index, and serum DDT levels, serum DDE levels were positively related to the risk of breast cancer (adjusted odds ratio (OR)Q1-Q2 = 1.24, 95% confidence interval (CI): 0.50, 3.06; ORQ1-Q3 = 2.31, 95% CI: 0.92, 5.86; ORQ1-Q4 = 3.81, 95% CI: 1.14, 12.80; test of trend, p = 0.02). The increased risk associated with higher serum DDE levels was more apparent among postmenopausal women (ORQ1-Q4 = 5.26, 95% CI: 0.80, 34.30; test of trend p = 0.03). A longer period of lactation was associated with a slightly decreased risk of breast cancer independently of serum DDE levels (OR = 0.91, 95% CI: 0.85, 0.99 change in risk per 10 months of lactation). Serum DDT level was not related to the risk of breast cancer. The data suggest that high levels of exposure to DDE may increase women's risk of breast cancer, particularly among postmenopausal women.     

Organochlorine pesticide levels in blood serum samples taken at autopsy from auto accident victims in Veracruz, Mexico

Samples of human blood sera (N = 118) for the determination of organochlorine pesticide levels were obtained at autopsy from auto accident victims in Veracruz, Mexico, during the years 2000 and 2001. The presence of hexachlorobenzene (HCH), beta-hexachlorocyclohexane (beta-HCH), 2,2-bis(p-chlorophenyl)-1,1-dichloroethylene (p,p'-DDE), 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (p,p'-DDT), and o,p'-DDT was confirmed by gas-liquid-electron-capture detection chromatography. During the years 2000 and 2001, the respective mean levels of (a) HCB, (b) beta-HCH, (c) p,p'-DDE, (d) o,p'-DDT, (e) p,p'-DDT, and (f) total DDT were (a) 2.1 ng/ml and 1.4 ng/ml, (b) 3.0 ng/ml and 3.6 ng/ml, (c) 21.1 ng/ml and 23.8 ng/ml, (d) 1.2 ng/ml and 0.8 ng/ml, (e) 3.3 ng/ml and 2.5 ng/ml, and, finally, (f) 25.4 ng/ml and 27.1 ng/ml, respectively. High levels of persistent organochlorine pesticides were--and continue to be--present in the blood of individuals who live in Mexico. Levels of insecticide metabolites (e.g., beta-HCH, p,p'-DDE) in blood have increased during recent years (1997-2001), but levels of p,p'-DDT decreased in 2001 because the use of DDT for the control of malaria in Mexico was restricted.     

CYP17 genotype modifies the association between lignan supply and premenopausal breast cancer risk in humans

Cytochrome P450c17alpha (CYP17) has been associated with alterations in steroid hormone levels and premenopausal breast cancer risk and could modify the association between phytoestrogen intake and breast cancer risk. We examined plasma concentrations of enterolactone and genistein, estimated dietary phytoestrogen intake, CYP17 5'-UTR MspA1 genetic polymorphism, and breast cancer risk in 267 premenopausal breast cancer patients and 573 age-matched population controls from Germany. Multivariate logistic regression was used to estimate breast cancer risk associated with quartiles of phytoestrogen intake by genotype and to investigate gene-nutrient interactions. Premenopausal breast cancer risk was not significantly associated with the CYP17 A2 genotype. We observed a significant modifying effect of CYP17 genotype on plasma enterolactone-associated breast cancer risk (P for interaction < 0.01). Plasma enterolactone was significantly inversely related to breast cancer risk only in A2A2 carriers, showing odds ratios and 95% CI of 0.02 (0.00-0.41) and 0.01 (0.00-0.21) for the third and fourth quartiles vs. the lowest quartile, respectively. This inverse association was also found for the calculated enterolignan production as well as matairesinol intake. Compared with A1A1 carriers with the lowest enterolactone supply, the risk reduction associated with a high enterolactone supply resulted in a comparably decreased breast cancer risk for all genotypes. For genistein, no clear indication for a differential effect by CYP17 genotype was obtained. Our results suggest that CYP17 genotype modifies the protective effect of lignans on premenopausal breast cancer risk. Women homozygous for A2 allele benefit most from high plasma enterolactone concentrations and a high consumption of dietary precursors.     

The CYP1A1 genotype may alter the association of meat consumption patterns and preparation with the risk of colorectal cancer in men and women

We hypothesized that the risk of colorectal cancer associated with meat preparation methods producing heterocyclic amines or polycyclic aromatic hydrocarbons is modified by the CYP1A1 genotype alone or in combination with the GSTM1 genotype or the NAT2 imputed phenotype. A total of 952 rectal cancer cases and 1205 controls (between September 1997 and February 2002) and 1346 colon cancer cases and 1544 controls (between October 1991 and September 1994) from Utah and Northern California were recruited from a population-based case-control study. Detailed interviews ascertained lifestyle, medical history, and diet and we extracted DNA from whole blood. Risk of colorectal cancer decreased among men with the CYP1A1 *2 any variant genotype and the lowest intake of poultry and men and women with high use of white meat drippings. Risk increased among men with the CYP1A1 *1 (no variant) allele and high white meat mutagen index, but decreased among those with the CYP1A1 *2 genotype. Risk increased with a high white meat mutagen index among women with the CYP1A1 *2 genotype and the GSTM1 present genotype. Risk of colorectal cancer decreased with the CYP1A1 *2 genotype, the NAT2 slow phenotype, and the use of white meat or its drippings. The association of risk for colorectal cancer and selected red and white meat mutagen indices and the use of white meat drippings, or fried white meat variables was more evident within select combinations of the CYP1A1 genotype and either the GSTM1 genotype or NAT2 than with the CYP1A1 alone. Genetic susceptibility may modify the associations of some meat or meat preparation factors with the risk of colorectal cancer.     

细胞色素P450基因多态及血清硒与肺癌的关系

目的 探讨细胞色素P450(A)(CYP1A1)的MSPI基因多态性、血清硒水平单独作用以及联合作用与肺癌发生危险性的关系。方法 采用成组病例一对照研究方法，病例58例，对照62例。用PCR-RFLP技术测定CYP1A1的MsPI多态性。用双道原子荧光光度计(GHAFS)测定血清硒水平。结果 CYP1A1的MsPI基因多态性单独作用时与肺癌危险性关系无显著性差异；病例组血清硒水平显著低于对照组(P=0．001)：以血清硒水平大于等于0．109mg／L。携带CYP1A1野生型者为参照组，则血清硒水平低于0．109mg／L且携带CYPlAl突变型或杂合型或携带野生型者OR分别为9．00(P=0．006)，3．94(P=0．195)，5．40(P=0．036)，而血清硒水平大于等于0．109mg／L携带突变型或携带杂合型者OR分别为1．69(P=0．500)，1．13(P=0．705)。结论 CYP1A1基因多态性单独作用时与肺癌发生无显著相关，血清硒水平与肺癌发生呈负相关；CYP1A1基因多态性与血清硒水平联合作用时明显提高肺癌发生的危险性，在肺癌发生中存在协同作用。     

DDT and breast cancer in young women: new data on the significance of age at exposure

BACKGROUND: Previous studies of DDT and breast cancer assessed exposure later in life when the breast may not have been vulnerable, after most DDT had been eliminated, and after DDT had been banned. OBJECTIVES: We investigated whether DDT exposure in young women during the period of peak DDT use predicts breast cancer. METHODS: We conducted a prospective, nested case-control study with a median time to diagnosis of 17 years using blood samples obtained from young women during 1959-1967. Subjects were members of the Child Health and Development Studies, Oakland, California, who provided blood samples 1-3 days after giving birth (mean age, 26 years). Cases (n = 129) developed breast cancer before the age of 50 years. Controls (n = 129) were matched to cases on birth year. Serum was assayed for p,p'-DDT, the active ingredient of DDT; o,p'-DDT, a low concentration contaminant; and p,p'-DDE, the most abundant p,p'-DDT metabolite. RESULTS: High levels of serum p,p'-DDT predicted a statistically significant 5-fold increased risk of breast cancer among women who were born after 1931. These women were under 14 years of age in 1945, when DDT came into widespread use, and mostly under 20 years as DDT use peaked. Women who were not exposed to p,p'-DDT before 14 years of age showed no association between p,p'-DDT and breast cancer (p = 0.02 for difference by age). CONCLUSIONS: Exposure to p,p'-DDT early in life may increase breast cancer risk. Many U.S. women heavily exposed to DDT in childhood have not yet reached 50 years of age. The public health significance of DDT exposure in early life may be large.     

Dichlorodiphenyldichloroethane burden and breast cancer risk: a meta-analysis of the epidemiologic evidence

The relationship of dichlorodiphenyltrichloroethane (DDT) exposure and breast cancer risk has received increasing attention since the beginning of the 1990s. Contradicting published results regarding the relationship between body burden levels of p,p'-dichlorodiphenyldichloroethane (p,p'-DDE)--the main DDT metabolite--and breast cancer, we argue that such differences stem from methodologic differences among those studies. We performed a meta-analysis of 22 articles using DerSimonian and Laird's method for random effects models. The Q-statistic was used to identify heterogeneity in the outcome variable across studies. The gradient of p,p'-DDE exposure in epidemiologic studies was homogenized to serum lipid bases (nanograms per gram). The potential for publication bias was examined by means of the Begg's test. We discuss methodologic features of the studies in an attempt to reconcile the findings. The summary odds ratio (OR) for selected studies was 0.97 (95% confidence interval, 0.87-1.09) and the gradient of exposure ranged from 84.37 to 12,948 ng/g. No overall heterogeneity in the OR was observed (chi-squared = 27.93; df = 23; p = 0.218). Neither the study design nor the lack of breast-feeding control or the type of biologic specimen used to measure p,p'-DDE levels were the causes of heterogeneity throughout the studies. Evidence for publication bias was not found (p = 0.253). Overall, these results should be regarded as a strong evidence to discard the putative relationship between p,p'-DDE and breast cancer risk. Nevertheless, the exposure to DDT during critical periods of human development--from conception to adolescence--and individual variations in metabolizing enzymes of DDT or its derivatives are still important areas to be researched in regard to breast cancer development in adulthood.     

唐山震后有机氯农药暴露与乳腺癌关系的病例对照研究

目的探讨唐山震后有机氯农药暴露与乳腺癌发生的关系。方法收集2006年4月—2007年6月在唐山市3家医院就诊的经病理学确诊的新发女性乳腺癌患者150例,以同期住院的非肿瘤、非生殖内分泌系统疾病的女性患者为对照,进行1∶1配比的病例对照研究。在进行流行病学调查的同时用气相色谱法测定血清中有机氯农药滴滴涕(DDT)和六六六(HCH)的含量。应用条件Logistic回归模型分析有机氯农药残留与乳腺癌发病的关系。结果 p,p’-DDD及o,p’-DDT两组检出率比较差异有统计学意义,病例组高于对照组;血清中p,p’-DDE、α-HCH及δ-HCH残留水平在乳腺癌病例组和对照组差异有统计学意义,病例组高于对照组,唐山震后农药不同暴露地区血清中δ-HCH、p,p’-DDE及o,p’-DDT残留水平差异有统计学意义,高暴露地区高于低暴露地区;多因素条件Logistic回归分析显示震后农药高暴露、p,p’-DDE和p,p’-DDT均与乳腺癌的发生有关联,OR值分别为6.592(95%CI:1.402～31.002)、2.405(95%CI:1.033～5.600)和1.845(95%CI:1.028～3.353)。结论环境有机氯农药暴露可能是乳腺癌发生的危险因素;唐山震后农药的高暴露可能增加当地乳腺癌的发病危险。