Dairy products, calcium and phosphorus intake, and the risk of prostate cancer: results of the French prospective SU.VI.MAX (Supplémentation en Vitamines et Minéraux Antioxydants) study

Population: Men aged 45-60 at baseline; cancer-free at start; 2776 analyzed; median follow-up 7.7 years. Design: analysis nested in SU.VI.MAX, a randomized, double-blind, placebo-controlled primary prevention trial.

Dairy product and dietary calcium intakes were associated with higher prostate cancer risk. Dairy intake: highest quartile vs lowest 1st quartile RR 1.35 (1.02–1.78); calcium intake: highest quartile RR 2.43 (1.05–5.62); dairy calcium RR 2.94 (1.16–7.51). Yoghurt: 125 g/d increment RR 1.61 (1.07–2.43) independent of calcium; fresh cheese in upper tertile RR 2.13 (1.09–4.15). Milk or cheese alone showed no significant association. Calcium–phosphorus interaction observed; higher risk linked largely to calcium in dairy, though yoghurt may have another component contributing. Authors conclude dairy products may harm prostate cancer risk largely via calcium content; further large European studies are needed to clarify effects of specific dairy foods.

Small number of cases (69); limited statistical power; strong correlation between calcium and phosphorus complicates disentangling independent effects; observational analysis within a trial; potential residual confounding; limited generalizability beyond French middle-aged men; dietary assessment relies on 24-h recalls, which may have measurement error.