Testing for Gene-Environment Interactions Using a Prospective Family Cohort Design: Body Mass Index in Early and Later Adulthood and Risk of Breast Cancer

Am J Epidemiol. 2017 Mar 15;185(6):487-500. doi: 10.1093/aje/kww241.


The ability to classify people according to their underlying genetic susceptibility to a disease is increasing with new knowledge, better family data, and more sophisticated risk prediction models, allowing for more effective prevention and screening. To do so, however, we need to know whether risk associations are the same for people with different genetic susceptibilities. To illustrate one way to estimate such gene-environment interactions, we used prospective data from 3 Australian family cancer cohort studies, 2 enriched for familial risk of breast cancer. There were 288 incident breast cancers in 9,126 participants from 3,222 families. We used Cox proportional hazards models to investigate whether associations of breast cancer with body mass index (BMI; weight (kg)/height (m)2) at age 18-21 years, BMI at baseline, and change in BMI differed according to genetic risk based on lifetime breast cancer risk from birth, as estimated by BOADICEA (Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm) software, adjusted for age at baseline data collection. Although no interactions were statistically significant, we have demonstrated the power with which gene-environment interactions can be investigated using a cohort enriched for persons with increased genetic risk and a continuous measure of genetic risk based on family history.

Keywords: BOADICEA; body mass index; breast cancer; cohort studies; familial risk; family studies; gene-environment interaction.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Australia / epidemiology
  • Body Mass Index*
  • Breast Neoplasms / epidemiology
  • Breast Neoplasms / etiology
  • Breast Neoplasms / genetics*
  • Family Health / statistics & numerical data*
  • Female
  • Follow-Up Studies
  • Gene-Environment Interaction*
  • Genetic Predisposition to Disease*
  • Humans
  • Middle Aged
  • New Zealand / epidemiology
  • Proportional Hazards Models
  • Prospective Studies
  • Reproductive History*
  • Risk Assessment / methods
  • Young Adult