CASE-CONTROL STUDY OF BREAST-CANCER IN SOUTH EAST ENGLAND - NUTRITIONAL FACTORS

Objectives-To explore dietary risk factors, in particular fat intake, for breast cancer, using an approach to reduce recall bias of subjects and so provide a more reliable estimate of dietary intake than previo us similar studies. Design-A case-control study of women aged 50-65 ye ars attending the breast assessment clinics of the breast screening pr ogramme in Southampton and Portsmouth, southern England. Data were ana lysed for all women requiring further clinical procedures; all women r ecalled to have an early rescreen; and a random sample of women found to be normal and referred for a routine rescreening appointment (stand ard recall). Measurements-An interview obtained information on various Lifestyle characteristics including smoking and alcohol intake, weigh t, waist, and hip measurements were also taken at the clinic. Women we re given a detailed questionnaire on food intake to complete at home a nd return by post. Results-1577 women were included in the study: 220 with breast cancer (cases); 179 with benign breast disease; 353 early rescreen and 825 given a standard recall appointment. There were few d ifferences in nutritional intake between the four groups. Logistic reg ression analyses were carried out comparing the dietary intake of case s with that of each control group adjusting for important demographic and reproductive factors. Results for the case and standard recall com parison are presented. The only non-calorific nutrient to reach signif icance was iron, which was negatively associated with risk (p=0.03). F or fat intake, the odds decreased with increasing polyunsaturated fat (p=0.15), showed no trend with monounsaturated fat (p=0.37) and increa sed (p=0.10) with increasing saturated fat. No pattern was clear for t he other calorie providing nutrients.Conclusions-In line with recent c ohort studies, this study has shown no evidence to support the hypothe sis that dietary fat is an important contributor to breast cancer rate s. Biases should have been reduced by studying subjects from the scree ning programme who were at an early stage of disease.