Social factors, diet and breast cancer in a northern Italian population

Abstract

Summary The relation of breast cancer to social and dietary variables was evaluated in a case-control study of 368 women with breast cancer admitted to the General Hospital of Pordenone (a town in the eastern side of Northern Italy) and 373 age-matched controls. Occupation was related to the risk of breast cancer, housewives and non-manual workers (teachers and other professionals, clerical workers, etc.) showing relative risks of 1.7 and 2.4 respectively when compared to women occupied in agriculture. The role of education was apparently less important, and not statistically significant. The risk was higher in women who were obese, the trend of increasing risk with increasing body mass index being confined to post-menopausal women.When indicators of dietary fat intake were analysed, a significantly increased risk was found with more frequent consumption of milk and dairy products but the risk estimates were only slightly above unity with reference to meat consumption.Women who drank alcoholic beverages showed a relative risk of 2.5 compared to women who had never drunk, when allowance was made for all identified potential confounding factors. The association between alcohol and breast cancer was not explained by the other dietary variables considered, and the risk estimates were higher for women who drank more wine, or more than one type of alcoholic beverage. Thus, the findings of the present study give evidence in favour of the hypothesis that alcohol consumption is related to the risk of breast cancer.

Cancer morbidity in alcohol abusers

“…In the last decade three cohort studies (Hiatt & Bawol, 1984;Schatzkin et al, 1987;Willet et al, 1987) and several case-control studies have shown a similar tendency for an increased risk of breast cancer in women with even a very light alcohol intake, i.e. a drink or so daily, compared with abstainers (Le et al, 1984;Talamini et al, 1984;La Vecchia et al, 1985;Harvey et al, 1987;O'Connell et al, 1987;Rohan & McMichael, 1988). This association has not been consistent (Byers & Funch, 1982;Begg et al, 1983;Paganini-Hill & Ross, 1983;Webster et al, 1983;Meara et al, 1989;Rosenberg et al, 1990).…”

“…The presumably lower socioeconomic status among the alcoholic women of the present cohort may cause some negative confounding (Talamini et al, 1984;O'Connell et al, 1987). Our results suggest that the association must be more complex than a direct effect of alcohol alone.…”

Cigarette smoking, alcohol consumption and risk of breast cancer in young women

“…Twenty-nine reported no change in consumption and one woman had decreased her wine intake (unpublished data). A positive association between alcohol and breast cancer has emerged not only in cohort but also in several case-control studies (Hammond, 1966;Williams & Horm, 1977;O'Connell, 1987;Le et al, 1984;Talamini et al, 1984;La Vecchia et al, 1985;Harvey et al, 1987). Taken together, these observations contradict the idea that recall bias due to our retrospective study design fully explained the discrepancy between our findings and those recently reported by other investigators.…”

“…Several case-control (Williams & Horm, 1977;O'Connell et al, 1987;Le et al, 1984;Talamini et al, 1984;La Vecchia et al, 1985;Harvey et al, 1987) and cohort (Hiatt & Bawol, 1984;Schatzkin et al, 1987;Willett et al, 1987) studies have shown an approximately 50-100% increase in the risk of developing breast cancer -particularly before menopause (O'Connell et al, 1987;Schatzkin et al, 1987;Willett et al, 1987) -in women who consume moderate or large amounts of alcohol. Accordingly, there is growing agreement that the association is causal and that in many populations exposure to alcohol might be a significant public health factor (Editorial, 1985;Graham, 1987).…”

“…There is accumulating evidence to indicate that the risk of developing breast cancer might be decreased in women who smoke (Hammond, 1966;Williams & Horm, 1977;Doll et al, 1980;Vessey et al, 1985;O'Connell et al, 1987), but that a moderate or high alcohol consumption entails an increased risk (Williams & Horm, 1977;O'Connell et al, 1987;Rosenberg et al, 1982;Hiatt & Bawol 1984; Le et al, 1984;Talamini et al, 1984;La Vecchia et al, 1985;Harvey et al, 1987;Schatzkin et al, 1987;Willett et al, 1987). A reasonable biological mechanism of the former relationship could be a reduction of oestrogenic activity in women who smoke, possibly as a result of decreased biosynthesis of oestrogen (MacMahon et al, 1982) or, which is more likely, of increased metabolic clearance of both endogenous (Michnovicz et al, 1986) and exogenous (Jensen et al, 1985) oestrogens.…”