title: Dichlorodiphenyltrichloroethane serum levels and breast cancer risk: a case-control study from Mexico.
abstract: Some, but not all, epidemiological studies have suggested that dichlorodiphenyltrichloroethane (DDT) may play a role in the development of breast cancer. These investigations have been conducted in countries where this substance has been banned for at least 20 years. We conducted a study in Mexico, a country in which DDT is still being used to control malaria. In a hospital-based case-control study, we compared 141 histologically confirmed cases of breast cancer with 141 age-matched controls (+/-3 years). All subjects were identified at three referral hospitals of Mexico City between March 1994 and April 1996. Reproductive histories and other variables were obtained by structured interviews, DDT/DDE levels were determined in serum by gas-liquid chromatography. The arithmetic mean of serum DDE in lipid basis was 562.48 +/- 676.18 ppb (range, 10.24-4661.44) for the cases and 505.46 +/- 567.22 ppb (range, 0.004 to 4361.75) for the controls, but this difference was not statistically significant. The age-adjusted odds ratios for breast cancer regarding the serum level of DDE were 0.69 (95% confidence interval, 0.38-1.24) and 0.97 (confidence interval, 0.55-1.70) for the contrasts between tertile 1 (lowest level) and tertiles 2 and 3, respectively. These estimates were unaffected by adjustment for body mass, accumulated time of breast-feeding and menopause, and other breast cancer risk factors. These results do not lend support to the hypothesis that DDT is causally related to breast cancer at the body-burden levels found in our study population but do not exclude the possibility that higher levels of exposure could still play a role in the etiology of this tumor.
authors.affiliation: National Institute of Public Health, Mexico Secretariat of Health, Cuernavaca, Morelos, Mexico.
authors.forename: L
authors.initials: L
authors.lastname: López-Carrillo
authors.forename: A
authors.initials: A
authors.lastname: Blair
authors.forename: M
authors.initials: M
authors.lastname: López-Cervantes
authors.forename: M
authors.initials: M
authors.lastname: Cebrián
authors.forename: C
authors.initials: C
authors.lastname: Rueda
authors.forename: R
authors.initials: R
authors.lastname: Reyes
authors.forename: A
authors.initials: A
authors.lastname: Mohar
authors.forename: J
authors.initials: J
authors.lastname: Bravo
mesh_terms: D000328:Adult; D000368:Aged; D001835:Body Weight; D001943:Breast Neoplasms / Q000097:blood* / Q000453:epidemiology; D002273:Carcinogens; D003634:DDT / Q000097:blood*; D005260:Female; D006801:Humans; D007306:Insecticides / Q000097:blood*; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D017584:Reproductive History; D012307:Risk Factors
chemical_list: D002273:Carcinogens; D007306:Insecticides; D003634:DDT