Low fat diet and skin cancer risk: the Women's Health Initiative Randomized Controlled Dietary Modification Trial
Mené auprès de 48 835 femmes ménopausées âgées de 50 à 79 ans (durée de suivi : 8 ans), cet essai randomisé évalue l'effet d'un régime alimentaire pauvre en graisses sur le risque de cancer de la peau hors mélanome
Background : Large cohort studies have reported no relationship between dietary fat and nonmelanoma skin cancer (NMSC), although a low-fat diet intervention reduced NMSC risk in a small clinical trial. In animal studies, skin tumor development has been reduced by low-fat diet. We evaluated the effect of a low-fat dietary pattern on NMSC and melanoma in the Women's Health Initiative Dietary Modification trial. Methods: Postmenopausal women aged 50 to 79 years (N=48,835) were randomly assigned to the low-fat dietary pattern intervention (N=19,541) or comparison group (N=29,294). The intervention goals included decreasing fat intake to ≤20% of calories, increasing vegetable and fruit intake, and increasing grain intake. Self-reported incident NMSC (N=4,907) and physician-adjudicated incident melanoma (N=279) were ascertained every 6 months. Results: Over 8.1 years of follow-up, the low-fat diet intervention did not affect overall incidence of NMSC (hazard ratio [HR] 0.98, 95% confidence interval [CI]: 0.92-1.04) or melanoma (HR 1.04, 95% CI: 0.82-1.32). In subgroup analyses of melanoma risk, baseline fat intake interacted significantly with group assignment (Pinteraction=0.006). Among women with higher baseline fat intake, the dietary intervention significantly increased risk (HR 1.48; 95% CI: 1.06-2.07), whereas, among women with lower baseline fat intake, the intervention tended to reduce melanoma risk (HR 0.72, 95% CI: 0.50-1.02). Conclusions: In this large randomized trial, a low-fat dietary pattern did not affect overall incidence of NMSC or melanoma. Impact: A low-fat diet does not reduce incidence of NMSC, but an interaction between baseline fat intake and dietary intervention on melanoma risk warrants further investigation.