Abstracts: ISEE 21st Annual Conference, Dublin, Ireland, August 25–29, 2009: Symposium Abstracts
DDT and its metabolite DDE or PCBs are persistent organochlorine compounds (OCs) with hormonal disrupting properties that are suspected to play a role in the etiology of breast cancers, but most epidemiological studies reported no link between OCs concentrations in biological tissues and breast cancer risk. In these studies, however, OCs were measured at only one point in time, generally close to the time of cancer diagnosis. The observed values may not be etiologically relevant exposure indicators, since they do not only reflect lifetime cumulative exposure, but also individual differences in metabolism and key events that affect OCs kinetics.
To identify the individual characteristics that influence DDE and PCBs concentrations among French women, using data collected for a large population-based case-control study on breast cancer.
The sample consisted of 2135 women who answered a detailed questionnaire on sociodemographic characteristics, reproductive history, height, weight history since puberty, diet, alcohol drinking and tobacco smoking. These women also gave a blood sample that was used to measure OCs concentrations. Statistical analyses were conducted using ordinal regression models.
The median concentration was 0.55μg/l for DDE and 0.61μg/l for total PCBs. The concentrations increased with age. In multivariate analyses, the factors that were independently associated with elevated DDE levels were high body mass index (BMI), low weight gain during the last 10 years, low parity among women younger than 50 years, and high consumption of freshwater fish among older women. The most important determinants of high PCB levels were low BMI, low weight gain during the last 10 years, high consumption of saltwater fish, and short duration of lactation among younger women.
These results are consistent with data derived from pharmacokinetic models. Several individual characteristics should be considered thoroughly when studying the role of OCs in breast cancer.