Susan A. Treloar1, Christine McDonald1, Nicholas G. Martin1
Early detection of cervical and breast cancer comprises important components of women's health strategy. Screening programs and preventive behaviors such as breast self-examination provide the means to this end. Our twin study sought to identify the relative influence of environmental and genetic factors on `liability' to early cancer detection behaviors, including use of cervical (Pap) smear tests, mammograms, and breast examination. Additive genetic and random environmental effects models gave the best, most parsimonious fit to the data for each early cancer detection behavior. The heritability of liability to Pap smear use was 66%, mammogram use 50%, breast examination by a doctor 38% and breast self-examination 37%. Genetic influences were behavior-specific; there was no evidence for a common genetic influence on the four behaviors. Potential covariates investigated included age, amount of contact between twins, educational level and personality traits such as harm avoidance, novelty seeking, reward dependence, neuroticism, anxiety, depression, self-esteem, perceived control, interpersonal dependency and ways of coping. None were significant. The importance of women's own agendas is highlighted. The study was carried out before the implementation of media campaigns to encourage awareness and increase participation rates. Hence follow-up investigation, including data on regularity of behaviors, would be informative.
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1Queensland Institute of Medical Research, Brisbane, Australia