Background: A number of epidemiological studies have examined the association between use of dairy products and risk of ovarian cancer, but results are conflicting. Using data from a large Danish population-based case-control study we here further examined the association between dairy consumption, lactose, and calcium and risk of overall ovarian cancer and histological types of ovarian cancer.
Material and methods: In the period 1995-1999 we included 554 women with epithelial ovarian cancer and 1554 randomly selected age-matched controls (35-79 years). All women participated in a detailed personal interview that included questions about dairy consumption. Data were analysed using multiple logistic regression models.
Results: Total dairy intake was associated with ovarian cancer risk (OR = 1.11; 95% CI: 1.07-1.15 per 100 ml/day). The association was strongest for milk [OR = 1.14; 95% CI: 1.03-1.27 per glass (200 ml)/day], soured milk products [OR = 1.49; 95% CI: 1.22-1.81 per portion (250 ml)/day] and yoghurt [OR = 1.65; 95% CI: 1.22-2.23 per portion (250 ml)/day]. In contrast, intake of cheese was associated with a decreased risk [OR = 0.70; 95% CI: 0.55-0.89 for > 1 portion (100 ml)/day compared with no intake]. Intake of lactose, but not calcium, was also associated with an increased ovarian cancer risk (OR = 1.24; 95% CI: 1.10-1.40 per 10 g of lactose/day). Similar risk patterns were observed for the different histological types of ovarian cancer, indicating virtually identical aetiologies with regard to dairy intake, lactose, and calcium.
Conclusions: Our results indicate that intake of dairy products is associated with a modest increased risk of ovarian cancer. In addition, ovarian cancer development was associated with lactose intake.