There is a large body of evidence suggesting that a low fat diet is related to lower risks of cancer and heart disease. The Women's Health Trial (WHT) will be a randomized clinical trial of the effect of a low fat diet on breast cancer incidence among 32,000 women. Since women generally do the food shopping and cooking for the entire family, this trial offers a unique opportunity to also explore the health benefits of a low fat diet among men. The primary aim of the proposed study is to determine if the husbands of the WHT women randomized to intervention experience a lower death rate, a lower incidence rate of cancer, and a lower incidence rate of fatal and nonfatal ischemic heart disease compared to the husbands of the control group women. Study subjects will be the estimated 25,300 husbands of the WHT participants. They will be followed yearly for endpoint determination, primary through their wives annual contact. All men will be asked to complete a food frequency questionnaire and a health history form, and a small subset of men will be asked to complete a four day diet record and a blood draw for serum cholesterol determination. The data will be analyzed using survival analysis techniques to determine whether the intervention and control groups differ in the endpoints of interest.