Energy, Nutrient Intake & Prostate Cancer Risk: A Population Based Case-Control Study In Sweden.
Energy, Nutrient Intake & Prostate Cancer Risk: A Population Based Case-Control Study In Sweden.
Year: 1996
Authors: Andersson, S-O. Wolk, A. Bergstrom, R. Giovannucci, E.L. Lindgren, C.
Publication Name: Int. J. Cancer
Publication Details: Vol 68; Pages 716-722.
Abstract:
The role of diet in the etiology of prostate cancer remains unclear, because results from several case-control and cohort studies on fat intake and risk of prostate cancer have been inconsistent; few of the studies have adjusted the results for caloric intake. To examine the relationship between energy, intake of several nutrients and risk of prostate cancer (all stages combined and advanced stages separately), we conducted a population-based case-control study in Orebro County, Sweden, from 1989 through 1994. A total of 526 patients with newly diagnosed prostate cancer and 536 controls, randomly selected from the population register and frequency-matched by age, were included in the analyses. Information about dietary intake was obtained from a self-administered semi-quantitative food frequency questionnaire. Odds ratios with 95% confidence intervals were estimated by unconditional logistic regression. In age-adjusted analyses, there were positive associations of prostate cancer (all stages combined) risk with total energy intake as well as intake of total fat (saturated and monounsaturated), protein, retinol and zinc. The positive association with energy intake was stronger for advanced cancer, with an excess risk of 70% for the highest quartile vs. the lowest. After adjustment for energy intake, there was no apparent association of prostate cancers (all stages combined) with any of the investigated nutrients. However, a weak positive association between intake of retinol and advanced cancer was observed. We conclude that our results provide some evidence that total energy intake is a risk factor for prostate cancer. (Author's Abstract)
Environmental factors including diet and in particular dietary fat appear to play a role in increasing incidence of prostate cancer. However, findings from epidemiological and cohort studies have been inconsistent with regard to the significance of both amount of fat and types of fatty acids. This population-based case-control study was one of the largest conducted in the 1990's to clarify further the role of diet in the etiology of prostate cancer. Patients with aggressive/advanced disease were analyzed separately, to test the hypothesis that dietary factors, especially fat, are involved in the progression of this malignancy. The findings showed a positive association between energy intake and risk of prostate cancer and no associations for specific macro- or micronutrients. The study does suffer from the possibility of recall bias in dietary data. And another methodological problem includes high correlations between many nutrients and energy intake. After energy adjustment, no clear associations between total fat, different types of fat (saturated, mono- and polyunsaturated) or specific fatty acids (linoleic and alpha-linolenic, ALA) and risk of prostate cancer were found. These findings contradict most previous case-control studies and some cohort studies but do lend support to the growing evidence that shows no, or very low association between ALA intakes and prostate cancer. Inconsistent findings between these types of studies are due largely to differences in study design, statistical power and analytic approaches. Some studies focused on fat intake as a nutrient and others on intake of foods rich in fat with or without adjustment for total energy intake. Further prospective studies are needed to clarify these divergent results. (Editor's comments)
Environmental factors including diet and in particular dietary fat appear to play a role in increasing incidence of prostate cancer. However, findings from epidemiological and cohort studies have been inconsistent with regard to the significance of both amount of fat and types of fatty acids. This population-based case-control study was one of the largest conducted in the 1990's to clarify further the role of diet in the etiology of prostate cancer. Patients with aggressive/advanced disease were analyzed separately, to test the hypothesis that dietary factors, especially fat, are involved in the progression of this malignancy. The findings showed a positive association between energy intake and risk of prostate cancer and no associations for specific macro- or micronutrients. The study does suffer from the possibility of recall bias in dietary data. And another methodological problem includes high correlations between many nutrients and energy intake. After energy adjustment, no clear associations between total fat, different types of fat (saturated, mono- and polyunsaturated) or specific fatty acids (linoleic and alpha-linolenic, ALA) and risk of prostate cancer were found. These findings contradict most previous case-control studies and some cohort studies but do lend support to the growing evidence that shows no, or very low association between ALA intakes and prostate cancer. Inconsistent findings between these types of studies are due largely to differences in study design, statistical power and analytic approaches. Some studies focused on fat intake as a nutrient and others on intake of foods rich in fat with or without adjustment for total energy intake. Further prospective studies are needed to clarify these divergent results. (Editor's comments)
