DDT induces DNA damage in blood cells. Studies in vitro and in women chronically exposed to this insecticide

In this study, DDT-induced DNA damage on blood cells was analyzed both in vitro and in vivo. Peripheral blood mononuclear cells (PBMC) were isolated from healthy donors and incubated in the presence of three different concentrations (40, 80, and 100 microg/mL) of p,p'-DDT, p,p'-DDE, and p,p'-DDD at three different treatment times (24, 48, and 72 h). Then, DNA damage was assessed by the single-cell electrophoresis assay (comet assay) as well as by flow cytometry detection of hypodiploid cells (DNA content assay). All compounds induced significant DNA damage as shown by the comet assay. Accordingly, cells exposed to DDT, DDE, and DDD showed a significant increase in the percentage of hypodiploid cells compared with untreated PBMC. In agreement with the in vitro data, a significant correlation between blood levels of DDT, DDD, and DDE and DNA damage (comet assay) was found in women with different amounts of environmental exposure. This association remained significant after controlling for nutritional status, smoking habits, alcohol ingestion, and reported exposure to other pesticides. Although the precise biological importance remains to be explained, our results strongly suggest that DDT and its metabolites are able to induce DNA damage in PBMC both in vitro and in vivo.     

Environmental pathways of exposure to DDT for children living in a malarious area of Chiapas, Mexico

Considering that DDT was used for control of malaria vectors in Mexico, and taking into account that the information regarding children in areas exposed to DDT is scarce, we started a research program for the assessment of health effects in children living in DDT sprayed areas. In this first report, we present information about pathways of exposure in two communities with a different history of exposure to DDT. Environmental pathways such as outdoor soils, indoor soils and household dust were assessed comparing a community highly exposed to DDT (HEC) and a community less exposed to DDT (LEC). Also in these communities, a cross-sectional study of 60 children (30 in each community) aged 6--12 years was conducted. Tests included a questionnaire and the measurement of whole blood DDT and DDE. Results show that in children living in the HEC, DDT and DDE mean blood levels were higher (15.9+/-8.2 and 58.2+/-29.2 microg/L) than in the LEC (1.9+/-3.6 and 9.2+/-5.7 microg/L) (P<0.01). Concentrations of DDT, DDE and DDD in indoor soil were higher in the HEC (10.3+/-10; 4.9+/-5.8; and 4.4+/-9.1mg/kg) than in the LEC (0.3+/-0.3; 0.04+/-0.06; and 0.03+/-0.04 mg/kg) (P<0.001). Similar results were obtained for outdoor soils; in the HEC, levels for DDT, DDE and DDD were 3.1+/-3.0; 1.0+/-0.8; and 0.3+/-0.2mg/kg; whereas levels in the LEC were 0.16+/-0.2; 0.02+/-0.03; and 0.02+/-0.03 mg/kg (P<0.001). High concentrations of DDT, DDE, and DDD were obtained in samples of indoor dust collected from the walls in the HEC (17.5+/-10.0; 5.5+/-6.2; and 9.8+/-16.8 mg/kg); levels in the LEC were lower (0.6+/-0.9; 0.07+/-0.1; and 0.05+/-0.07 mg/kg) (P<0.001). We did not find any correlation between blood levels of DDE and total DDT with environmental concentrations but there levels increased in LEC and HEC as the frequency of fish consumption increased (P<0.01).     

环卫女工月经情况及相关影响因素的调查

目的 目的了解南宁市青秀区环卫女工的月经状况,为开展环卫工人健康教育,改善他们的工作条件提供科学依据.方法 选择南宁市青秀区环卫队参加健康检查的730名街道清洁女工为调查对象(环卫组),另选机关事业单位参加健康检查女职工685名作为对照组,对2组女工进行月经情况的回顾性问卷调查.结果 调查发现环卫组月经异常发生率明显高于对照组,差异有统计学意义(x2 =40.62,P＜0.01);环卫组35岁以下各年龄组月经异常率与对照组相比,差异有统计学意义(P＜0.05);环卫组不同工龄月经异常率比较,差异无统计学意义(P＞0.05);环卫女工不良工作环境、高度紧张情绪、工作定量的超负荷、社会支持和福利满意度等因素是影响月经功能的主要因素.结论 环卫女工暴露于多种职业病有害因素中,这些因素均可干扰女性内分泌功能,引起月经异常,应加强环卫女工的劳动保护,切实保障她们的身体健康.     

DDT, DDE and DDD in Human Milk from South Africa

Human breast milk samples (n = 30) were collected from mothers within the age range of 19-40 years from Thohoyandou area, South Africa. DDT and its metabolites were extracted from the milk samples using diethyl ether. The crude extracts were subjected to column chromatography. The eluates were then evaporated on a stream of nitrogen up to 0.5 mL. One microliter of the cleaned extracts were injected into GC-ECD for selected organochlorine compounds. The sum total of DDT and its metabolites from each village ranged from not detectable for DMS, GNN and THN to 1,930 ng g(-1) fat wt for BDL while SigmaDDE ranged from 1.32 ng g(-1) fat wt for GNN to 2,570 ng g(-1) fat wt for TKD. SigmaDDD ranged from not detectable for GNN to 4,060 ng g(-1) fat wt for MNN. SigmaDDE was the most predominant followed by SigmaDDD and finally SigmaDDT. This was an indication of breakdown of the parent compound, DDT. Some villages namely, Lufule and Budeli, and Maniini and Makhuvha exhibited similar DDT occurrence of 89% in their areas. Other villages, DMS, TLM, and MND and TKD showed a similarity percentage of 82% while others showed similarities of 75% for GNN and MTT, 69% and 65% for MPG and THN respectively. A significant cluster of DDT and its metabolites between the infants' weight range of 2.5-3.9 kg/body wt was observed. Increase in lipid content was followed by a decrease in the sum DDT in the older mothers (27-30). The estimated daily intake varied from 260 to 4,696 ng/g, nd-10,551 ng/g and nd-4,237 ng/g for DDE, DDD and DDT respectively. These values are significantly (p < 0.05) higher than the FAO/WHO acceptable daily intake (ADI) of 20 ng/g. The SigmaDDT was found to decrease with increasing age of the mothers. The observed high levels of DDE compared to DDT indicated chronic exposure of the mothers to DDT, which is metabolised to DDE and retained in the body.     

DDE, a degradation product of DDT, and duration of lactation in a highly exposed area of Mexico

BACKGROUND: Higher levels of 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), the major degradation product of 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT), have been related to shorter duration of breast-feeding in previous studies. If DDE truly shortens lactation, this has public health importance regarding infant mortality and the use of DDT for malaria control. OBJECTIVE: Our aim was to assess the relationship of maternal DDE concentrations with length of subsequent lactation. METHODS: We conducted a relatively large study in a highly exposed area of Mexico. We followed 784 mother-son pairs to determine length of lactation. DDE and DDT were measured in maternal serum obtained within a day of delivery. We fit proportional hazard models with and without stratifying by previous breast-feeding, because an association of DDE with duration of lactation among those who breast-fed previously could be attributed to a noncausal mechanism. RESULTS: Compared with those with DDE concentrations < or = 3.00 microg/g, the adjusted hazard ratios of weaning according to DDE category were, for concentrations 3.01-6.00 microg/g, 1.27 [95% confidence interval (CI), 1.04-1.55]; for concentrations 6.01-9.00 microg/g, 1.23 (95% CI, 0.92-1.63); and for concentrations > 9.00 microg/g, 1.17 (95% CI, 0.92-1.49). The corresponding ratios for women who previously breast-fed were 1.40 (95% CI, 1.06-1.87); 1.91 (95% CI, 1.24-2.93); and 1.76 (95% CI, 1.22-2.53). Those for women who had not breast-fed previously were 1.14 (95% CI, 0.86-1.52); 0.90 (95% CI, 0.61-1.31); and 0.91 (95% CI, 0.66-1.26). CONCLUSIONS: Data from our relatively large study in a highly exposed area of Mexico did not support the hypothesis that exposure to DDE shortens length of lactation. The association seen in women who previously breast-fed was likely attributed to a noncausal mechanism. Nonetheless, whether DDT has other important adverse effects on humans is still an open question.     

DDT induces apoptosis in human mononuclear cells in vitro and is associated with increased apoptosis in exposed children

The aim of the present work was to investigate whether DDT and its metabolites are able to induce apoptosis of human peripheral blood mononuclear cells (PBMC) both in vitro and in vivo. Cells isolated from healthy individuals were incubated in the presence of increasing concentrations of p'p-DDT, p'p-DDE, or p'p-DDD (0-150 microg/mL) for different intervals. Apoptosis was then determined by flow cytometry (DNA cell content analysis) and fluorescence microscopy (Hoechst staining). A significant level of apoptosis was induced by DDT, DDD, and DDE at 80 microg/mL compared to controls, reaching a maximum effect at 100 microg/mL. We began to detect apoptosis at 12h, with a maximum effect at 24h of incubation. These results were confirmed using the TUNEL assay in cells treated with the three compounds tested as well as with o'p-DDT at 100 microg/mL and 24h of incubation. Our data demonstrate that DDT and its metabolites are able to induce apoptosis of human PBMC in vitro. Therefore, we performed a preliminary study in children exposed to this insecticide. When compared to a control population, the exposed children had higher levels of DDT, DDD, and DDE in blood and also had a higher frequency of apoptosis. In the exposed children, a weak positive association was found between the frequency of apoptosis and the exposure to DDT and DDE. Our results showed that more studies are needed in people exposed to DDT, as apoptosis may cause serious public health effects such as immunosuppression.     

Sex differences in the association of urinary bisphenol-A concentration with selected indices of glucose homeostasis among U.S. adults

PurposeEmerging evidence suggests that exposure to endocrine disruptors may initiate or exacerbate adiposity and associated health problems. This study examined sex differences in the association of urinary level of bisphenol-A (BPA) with selected indices of glucose homeostasis among U.S. adults.MethodsData analyses were performed using a sample of 1586 participants from the 2005 to 2008 National Health and Nutrition Examination Surveys. BPA level and the ratio of BPA-to-creatinine level were defined as log-transformed variables and in quartiles. Selected indices of glucose homeostasis were defined using fasting glucose and insulin data. Multivariate linear and logistic regression models for the hypothesized relationships were constructed after controlling for age, sex, race, education, marital status, smoking status, physical activity, total dietary intake, and urinary creatinine concentration.ResultsTaking the first quartile as a referent, the third quartile of BPA level was positively associated with log-transformed level of insulin and β-cell function (homeostasis model assessment for β-cell function) as well as insulin resistance (log-transformed homeostasis model assessment for insulin resistance; homeostasis model assessment for insulin resistance ≥2.5), with significant BPA-by-sex interaction; these associations were stronger among males than among females. Irrespective of sex, the ratio of BPA-to-creatinine level was not predictive of indices of glucose homeostasis.ConclusionsA complex association may exist between BPA and hyperinsulinemia among adult U.S. men. Prospective cohort studies are needed to further elucidate endocrine disruptors as determinants of adiposity-related disturbances.     

Nonmalarial infant deaths and DDT use for malaria control

Although dichlorodiphenyl trichloroethane (DDT) is being banned worldwide, countries in sub-Saharan Africa have sought exemptions for malaria control. Few studies show illness in children from the use of DDT, and the possibility of risks to them from DDT use has been minimized. However, plausible if inconclusive studies associate DDT with more preterm births and shorter duration of lactation, which raise the possibility that DDT does indeed have such toxicity. Assuming that these associations are causal, we estimated the increase in infant deaths that might result from DDT spraying. The estimated increases are of the same order of magnitude as the decreases from effective malaria control. Unintended consequences of DDT use need to be part of the discussion of modern vector control policy.     

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[icaron]-DDT]) and its principal metabolite, 1,1-dichloro-2,2-bis (p-chlorophenyl)ethylene [p,p[icaron]-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[icaron]-DDT (range: 56–23,169 ng/g) and 4,843 ng/g p,p[icaron]-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.     

国内常用避孕药具对女性人群月经影响的研究

通过对使用国内常用16种避孕药具的10万例女性人群,采用流行病学调查方法,对月经周期、每次月经持续时间、痛经等指标进行分析、评价。结果显示:各种避孕药具3项指标异常率各异,月经周期异常率为10.25%,每次月经持续时间异常率为8.40%,痛经发生率为7.67%。     

Nutrient and food intake in relation to serum leptin concentration among young Japanese women

OBJECTIVE: Little is known about the relation of modifiable dietary factors to circulating leptin concentrations, particularly in young adults and non-Western populations. We examined cross-sectional associations between nutrient and food intake and serum leptin concentration in young Japanese women. METHODS: Subjects were 424 female Japanese dietetic students 18-22 y of age. Intake of macronutrients (protein, total fat; saturated, monounsaturated, and polyunsaturated fatty acids; and carbohydrate), dietary fiber, and 12 food groups was assessed with a validated, self-administered, comprehensive, diet history questionnaire. Fasting blood samples were collected, and serum leptin concentrations were measured by radioimmunoassay. RESULTS: For nutrients, only dietary fiber was a significant determinant of serum leptin concentration. Increasing dietary fiber intake was associated with lower serum leptin concentration independent of potential confounding factors, including body mass index (mean serum leptin concentrations in the lowest and highest quintiles of dietary fiber intake were 8.6 and 7.5 ng/mL, respectively; P for trend = 0.026). Vegetables and pulses were the only foods significantly associated with serum leptin concentration, with higher intakes independently associated with lower concentrations (mean serum leptin concentrations in the lowest and highest quintiles of intake were 8.1 and 7.0 ng/mL, P for trend = 0.007, for vegetables and 8.8 and 7.6 ng/mL, P for trend = 0.019, for pulses, respectively). CONCLUSION: Intake of dietary fiber, vegetables, and pulses showed an independent inverse association with serum leptin concentration in a group of young Japanese women.     

Dibutyl-phthalate exposure from mesalamine medications and serum thyroid hormones in men

Background

Dibutyl phthalate (DBP) is an endocrine disruptor and used in some medication coatings, such as mesalamine for treatment inflammatory bowel disease (IBD).

Exposure to 1,1-Dichloro-2,2-bis(p-chlorophenyl)ethylene (DDT) in Relation to Bone Mineral Density and Rate of Bone Loss in Menopausal Women

The organochlorine pesticide 2,2-bis(p-chlorophenyl)-1,1,1-trichloroethane (DDT) and its metabolite 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) are examples of an environmental contaminant that may have hormonal properties. Bone metabolism is both estrogen- and androgen-dependent. Exposures to various environmental endocrine disrupters can affect bone metabolism in animals, but there are no published data concerning the effect of DDE exposure on bone metabolism in humans. We hypothesized that high levels of DDE would be associated with lower bone density in peri- and postmenopausal women than in premenopausal women. Study subjects were drawn from the cohort of women who had participated in the Mount Sinai Medical Center Longitudinal Normative Bone Density Study (1984-1987). We used serum samples obtained at study entry to measure DDE levels in 103.(50 black, 53 white) women (mean age = 54.5 y [standard deviation = 5 y]). Measurements of bone mineral density at the lumbar spine and radius were made at 6-mo intervals during a 2-y period. DDE concentrations were significantly (p < .001) higher in blacks (13.9 ng/ml) than in whites (8.4 ng/ml), but there was no correlation between DDE concentration and bone density at the spine (mean levels = 1.065 g/cm² and 1.043 g/cm² in the lowest and highest quartiles, respectively, of DDE [trend p value = .85]) or at the radius (mean levels = 0.658 g/cm and 0.664 g/cm in the lowest and highest quartiles, respectively, of DDE [trend p value = .34]). Longitudinal analyses revealed no correlation between DDE and the rate of bone loss at either bone site. Similar results were seen in race-stratified analyses, as well as in analyses in which we controlled for lactation history and other potential confounders. We found little evidence that chronic low-level DDT exposure is associated with bone density in peri- and postmenopausal women.     

The Pine River Statement: Human Health Consequences of DDT Use

Objectives

Dichlorodiphenyltrichloroethane (DDT) was used worldwide until the 1970s, when concerns about its toxic effects, its environmental persistence, and its concentration in the food supply led to use restrictions and prohibitions. In 2001, more than 100 countries signed the Stockholm Convention on Persistent Organic Pollutants (POPs), committing to eliminate the use of 12 POPs of greatest concern. However, DDT use was allowed for disease vector control. In 2006, the World Health Organization and the U.S. Agency for International Development endorsed indoor DDT spraying to control malaria. To better inform current policy, we reviewed epidemiologic studies published from 2003 to 2008 that investigated the human health consequences of DDT and/or DDE (dichlorodiphenyldichloroethylene) exposure.

Data sources and extraction

We conducted a PubMed search in October 2008 and retrieved 494 studies.

Data synthesis

Use restrictions have been successful in lowering human exposure to DDT, but blood concentrations of DDT and DDE are high in countries where DDT is currently being used or was more recently restricted. The recent literature shows a growing body of evidence that exposure to DDT and its breakdown product DDE may be associated with adverse health outcomes such as breast cancer, diabetes, decreased semen quality, spontaneous abortion, and impaired neurodevelopment in children.

Conclusions

Although we provide evidence to suggest that DDT and DDE may pose a risk to human health, we also highlight the lack of knowledge about human exposure and health effects in communities where DDT is currently being sprayed for malaria control. We recommend research to address this gap and to develop safe and effective alternatives to DDT.     

The hormonal effects of long-term DDT exposure on malaria vector-control workers in Limpopo Province, South Africa

DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane] compounds, used in many developing countries, including South Africa, for the control of malaria vectors, have been shown to be endocrine disruptors in vitro and in vivo. The study hypothesis was that male malaria vector-control workers highly exposed to DDT in the past should demonstrate clinically significant exposure-related anti-androgenic and/or estrogenic effects that should be reflected in abnormalities in reproductive hormone levels. A cross-sectional study of 50 workers from three camps situated near the Malaria Control Center (MCC) in Tzaneen was performed. Tests included blood sampling before and after a gonadotropin-releasing hormone (GnRH) challenge (100 microg). Serum o'p' and p'p' isomers of DDE, DDT, and DDD and basal and post-GnRH challenge hormone levels, including luteinizing hormone, follicle-stimulating hormone, testosterone, sex hormone-binding globulin, estradiol (E2), and inhibin, were measured. The mean number of years worked at the MCC was 15.8+/-7.8 years and the mean serum DDT was 94.3+/-57.1 microg/g of lipid. Mean baseline E2 levels (62.4+/-29.9 pg/mL) exceeded the laboratory reference range. Associations between DDT exposure measures (years worked at the MCC and DDT compounds) and hormonal outcomes were weak and inconsistent. The most important finding was a positive relationship of baseline E2 and baseline testosterone with DDT compounds, especially with p'p'-DDT and -DDD. The strongest association found, adjusted for age and SHBG, was between baseline estradiol and p'p'-DDT (beta=1.14+/-0.33 pg/mL/microg/ g lipid, P=0.001, R2=0.31, n=46). An overall anti-androgenic mechanism best explains the results, but with a number of inconsistencies. Associations might be due to chance, as multiple comparisons were made. The results therefore do not suggest an overt anti-androgenic or estrogenic effect of long-term DDT exposure on hormone levels, but correlations do exist in a manner that is not understood.     

某大学女生月经及痛经情况调查

目的:了解大学女生月经及痛经的情况,做好青春期卫生保健防病指导工作。方法:采用自制调查表,对不同专业、不同年级的女生进行问卷调查,回收答卷后进行统计分析。结果:共发放问卷1 000份,收回973份。女大学生的初潮年龄在12～15岁,占调查总人数的86.20%,平均初潮年龄为(13.28±1.36)岁;493例有痛经,占总人数的50.67%;经期伴随症状发生率较高;不同年级对痛经发生率有一定影响。结论:发放月经生理常识手册,加强自我保健知识的健康教育,普及正确预防与治疗月经异常和痛经的知识有利于提高青春期保健水平。     

中国六城市女性生理生育因素与乳腺癌关系的病例对照研究

目的研究城市女性乳腺癌的危险因素,探讨城市女性生理生育因素的变化与城市女性乳腺癌发病的关联强度,促进乳腺癌的预防和控制。方法采用病例对照的研究方法,新发病例通过北京、天津、上海、重庆、武汉、广州六城市的乳腺癌监测点确定,对照从当地正常人群数据库中随机抽样,对收集到3332对1：1年龄配对的病例和对照进行问卷调查。通过条件Logistic模型进行相对危险度及剂量-反应效应估计。结果在调整年龄、职业、饮食等因素后,城市女性中乳腺癌发病的危险因素为初潮年龄的提前（≤14岁,OR=1.37,95％CI=1.12－1.66）、月经持续天数长（〉7天,OR=1.18,95％ CI=1.00－1.38）、有痛经（OR=1.21,95％ CI=1.03－1.42）、结婚晚（≥28岁,OR：2.13,95％ CI=1.63－2.79）、首次怀孕晚（≥30岁,OR=2.13,95％CI=1.63－2.79）等,而保护性因素有月经间隔天数长（ 〉28天,OR=0.81,95％ CI=0.68－0.95）、绝经年龄早（≤45岁,OR=0.58,95％ CI=0.47－0.72）、怀孕次数多（≥2次,OR=0.67,95％ CI=0.45－0.99）,哺乳（≥4个月,OR=0.70,95％CI：0.60－0.83）。结论女性生理生育因素是影响城市女性乳腺癌发病的主要危险因素,可部分解释中国城市女性乳腺癌呈逐年上升趋势的原因。     

Exposures associated with serum organochlorine levels among postmenopausal women from western New York State

BACKGROUND: Organochlorines, such as 2,2-bis (4-chlorophenyl)-1,1-dichloroethylene (DDE), polychlorinated biphenyls (PCBs), and hexachlorobenzene (HCB) are lipophilic compounds that are ubiquitous in the environment and may cause adverse health effects in humans. METHODS: We examined the correlation between epidemiological exposure variables and serum DDE, PCB, and HCB levels in a sample of 192 healthy, female postmenopausal western New York residents; a subset of the control group from a case-control study on breast cancer risk. Usual diet, reproductive and medical histories, and other lifestyle information were obtained by an extensive in person interview. Serum levels (ng/g) of DDE, HCB, and 69 PCB congeners were determined by gas chromatography with electron capture detection. Statistical analyses included computations of crude and age and lipid adjusted correlation coefficients, as well as multiple linear regression analysis. RESULTS: Results indicated that the strongest predictors for serum DDE levels were age, serum lipids, parity, and fruit and dairy consumption. Statistically significant predictors of PCB levels included age, serum lipids, parity, and fish consumption. Serum HCB levels were related to age, serum lipids, and fruit and red meat consumption. CONCLUSIONS: Our findings are consistent with previous investigations that reported strong associations between organochlorine levels and age and serum lipids. The absence of other data showing an association between fruit intake and organochlorine levels make the importance of this finding unclear.     

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。