Metabolic factors and breast cancer risk in Korean women

Metabolic factors have been suggested to be associated with breast cancer. However, the findings are inconsistent among studies. We conducted a case-control study in Korean women to evaluate the association between metabolic factors and premenopausal and postmenopausal breast cancer. Incident breast cancer cases (270 women) and their controls (540 women) matched by age and menopausal status were recruited from the recipients of a health examination at the same institution. Five relevant factors of metabolic syndrome were evaluated. Odds ratios (OR) and 95 % confidence intervals (CI) for the association were estimated by conditional logistic regression analysis. Proportions of cases and controls with each factors were 25.6 and 20.6 % for obesity (body mass index a parts per thousand yen 25 kg/m(2)), 17.4 and 17.4 % for high fasting glucose (a parts per thousand yen5.55 mmol/L or use of hypoglycemic medication), 13.0 and 18.9 % for high triglyceride (a parts per thousand yen1.69 mmol/L), 26.3 % and 23.9 % for low high-density lipoprotein cholesterol (< 1.29 mmol/L), and 29.6 and 30.6 % for high blood pressure (a parts per thousand yen130/or 85 mmHg or use of antihypertensive medication), respectively. Although only the obesity was associated with an increased risk of postmenopausal breast cancer (OR = 2.24; 95 % CI 1.22-4.10) among individual metabolic factors, women with aggregation of three or more metabolic factors as defined by international diabetes federation criteria showed greater risk for postmenopausal breast cancer compared with women without any factor (OR = 2.36; 95 % CI 1.10-5.10). Although obesity was the only metabolic factor associated with postmenopausal breast cancer, the presence of other metabolic factors may further increase the risk of postmenopausal breast cancer when combined with obesity.