DIETARY LACTOSE INTAKE, LACTOSE-INTOLERANCE, AND THE RISK OF EPITHELIAL OVARIAN-CANCER IN SOUTHERN ONTARIO (CANADA)

A case-control study of dietary factors and cancer of the ovary was co nducted during 1989-92 in metropolitan Toronto and surrounding areas o f southern Ontario, Canada. Four hundred and fifty women aged 35-79 ye ars, with newly diagnosed, histologically verified, primary epithelial ovarian-cancer were interviewed concerning reproduction and diet. Ove r the same period, 564 randomly-selected population controls, frequenc y-matched to the cases within three 15-year age groups, also were inte rviewed. From information obtained by quantitative diet history, avera ge daily macro- and micronutrient intake values were calculated throug h use of the United States Department of Agriculture Food Composition Databank, which was extended and modified for Canadian items and recip es. Analysis was performed with continuous, unconditional logistic-reg ression methods, adjusting for age at interview, number of full-term p regnancies, total duration of oral contraceptive use, and total daily caloric intake. Neither reported history of lactose intolerance, nor a verage daily consumption of lactose or free galactose, were found to b e associated with risk of ovarian cancer. Lactose intake or intoleranc e did not appear to modify the protective effects of parity and oral c ontraceptive use. Nevertheless, other studies suggest that ovarian gal actose metabolism still may have a relationship with risk of ovarian c ancer, though more evidence is needed.