Excessive energy intake and cancer risk

Excessive energy intake is related to obesity and to free-radicals formation, two conditions that have been shown to increase cancer risk. We evaluated the association between excessive energy intake and cancer risk in an Italian network of case-control studies on 12 cancer types. Cases were 10,753 patients with incident, histologically confirmed, cancer. Controls were 24,245 cancer-free patients matched to cases by sex, age, and place of living. Daily Energy Requirement (DER) was estimated from height, ideal weight, sex, age, and self-reported physical activity. Caloric Balance (CB) was calculated as the difference between daily energy intake (estimated from dietary habits in the years preceding enrolment, assessed through a food-frequency questionnaire) and DER. Odds ratios (OR) and confidence intervals (CI) for excessive energy intake (i.e., CB500 kCal/day) compared to proper one (i.e., -150CB<150 kCal/day) were calculated using logistic regression model, adjusted for relevant confounders. Cancer cases reported significantly higher CB than controls (median=243 and 97 kCal/day, respectively; Wilcoxon p<0.01). Excessive energy intake was associated to increased risk of cancers of the larynx (OR=1.83; 95% CI: 1.27-2.63), colon (OR=1.33; 95% CI: 1.12-1.58), rectum (OR=1.32; 95% CI: 1.06-1.63), postmenopausal breast (OR=1.21; 95% CI: 1.01-1.49), pancreas (OR=1.52; 95% CI: 1.01-2.38), and prostate (OR=1.39; 95% CI: 1.07-1.82). No significant associations emerged for cancers of the head and neck, oesophagus, nasopharynx, endometrium, ovary, and kidney. Study results highlight the importance of an appropriate CB in the prevention of several cancers. Therefore, monitoring daily energy intake and increasing physical activity should be strongly recommended.