Milk and lactose intakes and ovarian cancer risk in the Swedish Mammography Cohort.
BACKGROUND
High intakes of dairy products and of the milk sugar lactose have been hypothesized to increase ovarian cancer risk, but prospective data are scarce.


OBJECTIVE
We examined the association between intakes of dairy products and lactose and the risk of total epithelial ovarian cancer and its subtypes.


METHODS
This was a prospective population-based cohort study of 61 084 women aged 38-76 y who were enrolled in the Swedish Mammography Cohort. Diet was assessed in 1987-1990 with the use of a self-administered food-frequency questionnaire. During an average follow-up of 13.5 y, 266 women were diagnosed with invasive epithelial ovarian cancer; 125 of those women had serous ovarian cancer.


RESULTS
After adjustment for potential confounders, women who consumed >/=4 servings of total dairy products/d had a risk of serous ovarian cancer (rate ratio: 2.0; 95% CI: 1.1, 3.7; P for trend = 0.06) twice that of women who consumed <2 servings/d. No significant association was found for other subtypes of ovarian cancer. Milk was the dairy product with the strongest positive association with serous ovarian cancer (rate ratio comparing consuming >/=2 glasses milk/d with consuming milk never or seldom: 2.0; 95% CI: 1.1, 3.7; P for trend = 0.04). We observed a positive association between lactose intake and serous ovarian cancer risk (P for trend = 0.006).


CONCLUSIONS
Our data indicate that high intakes of lactose and dairy products, particularly milk, are associated with an increased risk of serous ovarian cancer but not of other subtypes of ovarian cancer. Future studies should consider ovarian cancer subtypes separately.
Larsson
Susanna C
SC
Division of Nutritional Epidemiology, The National Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden. susanna.larsson@imm.ki.se
Bergkvist
Leif
L
Wolk
Alicja
A
D000328:Adult; D000368:Aged; D000818:Animals; D015992:Body Mass Index; D015331:Cohort Studies; D004032:Diet; D005260:Female; D006801:Humans; D015994:Incidence; D007785:Lactose / Q000008:administration & dosage / Q000009:adverse effects*; D008875:Middle Aged; D008892:Milk / Q000009:adverse effects*; D010051:Ovarian Neoplasms / Q000209:etiology*; D012306:Risk; D011795:Surveys and Questionnaires; D013548:Sweden / Q000453:epidemiology
D007785:Lactose