Breast cancer risk and the combined effect of environmental estrogens.
OBJECTIVE
The present study aimed to determine whether the combined effects of environmental estrogens measured as the total effective xenoestrogen burden (TEXB-alpha) are a risk factor for breast cancer over and above the risk potentially linked to specific pesticides.


METHODS
We measured the levels of 16 organochlorine pesticides as well as TEXB in adipose tissue of 198 women at the time of breast cancer diagnosis. These were compared with findings in 260 age and hospital matched control women without breast cancer.


RESULTS
The median levels of p,p'-DDE (1,1-dichloro-2,2-bis( p -chlorophenyl)ethylene), aldrin, endosulfan ether and lindane (the pesticides detected in > 40% of the study population) were higher in cases than controls, although the differences did not reach statistical significance. After adjusting for potential confounders, the odds ratio (OR) for breast cancer in women with detectable levels of aldrin was 1.55 (95% confidence interval (CI) 1.00-2.40). Among the postmenopausal women, the OR for aldrin and lindane was 1.84 (95% CI 1.06-3.18) and 1.76 (95% CI 1.04-2.98), respectively. Among cases with body mass index (BMI) below the median (28.6 kg/m2), the OR was 3.42 (95% CI 1.22-9.58) for women in the highest quartile of TEXB-alpha versus those in the lowest. The subgroup of leaner postmenopausal women showed an increased risk (OR: 5.67; 95% CI 1.59-20.21) for those in the highest tertile versus those in the lowest.


CONCLUSIONS
We found an increased risk for breast cancer in the leaner women, especially in the leaner postmenopausal subgroup, related to the TEXB-alpha. The pesticides aldrin and lindane are also individually associated with risk.
Department of Health Guipuzkoa, San Sebastián, Basque Country, Spain.
Jesús m
Jm
Ibarluzea Jm
Mariana F
MF
Fernández
Loreto
L
Santa-Marina
Maria F
MF
Olea-Serrano
Ana M
AM
Rivas
Juan J
JJ
Aurrekoetxea
José
J
Expósito
Miguel
M
Lorenzo
Pablo
P
Torné
Mercedes
M
Villalobos
Vicente
V
Pedraza
Annie J
AJ
Sasco
Nicolas
N
Olea
D000273:Adipose Tissue / Q000737:chemistry; D000328:Adult; D000368:Aged; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000209:etiology*; D016022:Case-Control Studies; D004967:Estrogens / Q000493:pharmacokinetics* / Q000506:poisoning*; D005260:Female; D006801:Humans; D006843:Hydrocarbons, Chlorinated; D007306:Insecticides / Q000493:pharmacokinetics* / Q000506:poisoning*; D008875:Middle Aged; D017698:Postmenopause; D012307:Risk Factors; D015262:Xenobiotics / Q000493:pharmacokinetics / Q000506:poisoning
D004967:Estrogens; D006843:Hydrocarbons, Chlorinated; D007306:Insecticides; D015262:Xenobiotics