Dietary antioxidant vitamins, retinol, and breast cancer incidence in a cohort of Swedish women.

Dietary antioxidant vitamins and retinol have been proposed to be protective against breast cancer on the basis of their ability to reduce oxidative DNA damage and their role in cell differentiation. Epidemiologic studies have not been convincing in supporting this hypothesis, but women with high exposure to free radicals and oxidative processes have not been specifically considered. We explored these issues in the Swedish Mammography Screening Cohort, a large population-based prospective cohort study in Sweden that comprised 59,036 women, 40-76 years of age, who were free of cancer at baseline and who had answered a validated 67-item food frequency questionnaire. During 508,267 person-years of follow-up, 1,271 cases of invasive breast cancer were diagnosed. Cox proportional hazards models were used to obtain hazard ratios (HRs) and 95% confidence intervals (CIs). There was no overall association between intake of ascorbic acid, beta-carotene, retinol or vitamin E and breast cancer incidence. High intake of ascorbic acid was inversely related to breast cancer incidence among overweight women (HR=0.61; 95% CI 0.45-0.82, for highest quintile of intake among women with body mass index>25 kg/m(2)) and women with high consumption of linoleic acid (HR=0.72; 95% CI 0.52-1.02, for highest quintile of ascorbic acid intake and average consumption of more than 6 grams of linoleic acid per day). Among women with a body mass index of 25 or below, the hazard ratio for breast cancer incidence was 1.27 (95% CI 0.99-1.63), comparing the highest to the lowest quintile of ascorbic acid intake. Consumption of foods high in ascorbic acid may convey protection from breast cancer among women who are overweight and/or have a high intake of linoleic acid.

Cholecystectomy in Sweden 1989 and 1994: long admissions assessed by the inpatient registry.

The purpose of this study was to compare cholecystectomy in Sweden (pop. 8.9 million) 1989 to 1994 when the diffusion of laparoscopic cholecystectomy (LC) was completed, focusing on long hospital admissions as a proxy indicator of adverse events. This was an observational study of all patients operated on with cholecystectomy in 1989 and 1994 (n = 19,432) from the National Inpatient Registry. The risk of a long admission was analyzed by multivariate analyses. Odds ratios of long admissions were computed considering gender, age groups, acute or chronic gallstone disease, 1989 and 1994, county level of operations per 1000 inhabitants, and hospital categories. Stratified analyses were performed by acuteness of disease, and year. Long admissions were defined as lasting longer than 20 days in 1989 and 14 days in 1994. Odds ratios of a long admission increased steeply with age and acute gallstone disease. The county level of operations per 1000 inhabitants had no influence on risk nor did hospital category. The absolute number of those operated on with an acute gallstone disease changed little between 1989 and 1994, whereas operations for chronic disease increased significantly. Stratification revealed that their risk of a long admission was increased both in 1989 and 1994, particularly for women. Those with chronic gallstone disease had no increased risk. After the introduction of the laparoscope and a rise in the number of cholecystectomies, patients with chronic gallstone disease seem to have a constant risk of long hospital stay. However, because patients with acute disease had an increased risk in both 1989 and 1994, further longitudinal analyses are needed to analyze the level of complications in this group.

Appendectomy in Sweden 1989-1993 assessed by the Inpatient Registry.

We analyzed all appendectomies in Sweden 1989-1993 (n = 60,306) recorded in the national Inpatient Registry. Our focus was on diagnostic accuracy, incidence rate of appendicitis, perforative appendicitis, and length of stay by day of admission and hospital category. The incidence rate of appendectomy decreased by 9.8% in women compared to 4.1% in men. Since the number of patients with an end diagnosis of appendicitis remained almost constant, diagnostic accuracy increased each year. This was more pronounced in women than men, seen in all hospital categories, and was higher for those admitted during periods of low capacity (weekends/ holidays). Perforated appendicitis did not increase. Duration of hospital stay decreased continuously, especially among the oldest. We found no indications of an increased frequency of complications, such as increases in the incidence rate of perforations or in the length of stay.

Evaluation of a biological marker of dairy fat intake.

We evaluated whether the adipose tissue content of 2 fatty acids of exogenous origin specific for ruminant fat, 15:0 and 17:0, reflect average long-term dairy fat consumption in free-living subjects. In 81 healthy women aged 30-77 y, we compared the relative content of these 2 fatty acids in subcutaneous adipose tissue with relative intake (% of total fat) based on four 1-wk weighed diet records made 3-4 mo apart and on a food-frequency questionnaire reflecting average past year consumption. The mean (+/-SD) daily milk fat intake was 20.0 +/- 9.1 g and fat from ruminant meat was 3.0 +/- 1.5 g according to food records, representing 29.2 +/- 8.9% and 4.6 +/- 2.2% of total fat, respectively. The intake of 15:0 and 17:0, which are 1.05% and 0.61% of milk fat and 0.43% and 0.83% of ruminant meat fat, was 0.22 +/- 0.10 and 0.15 +/- 0.06 g, respectively. Content of 15:0 and 17:0 in adipose tissue was 0.35% and 0.24% and relative dietary intake was 0.33% and 0.22% according to the food records and 0.32% and 0.21%, respectively, according to the food-frequency questionnaire. Correlation coefficients between 15:0 content in adipose tissue and intake from dairy foods only, according to food records, were 0.63 (Pearson) and 0.59 (Spearman); corresponding values for 17:0 were 0.42 and 0.45, respectively. Content of 15:0 and 17:0 in subcutaneous adipose tissue might be a valid biological marker of long-term milk fat intake in free-living individuals in populations with high consumption of dairy products.

Effect of additional questions about fat on the validity of fat estimates from a food frequency questionnaire. Study Group of MRS SWEA.

OBJECTIVE: We studied whether the validity of fat estimates from food frequency questionnaires (FFQ) can be increased by using in nutrient calculation an additional qualitative information about the type of fat and reduced consumption of visible fat and skin. DESIGN: A random sample of women answered an 88-item self-administered FFQ and performed 4 x 1-week weighed dietary records (DR). SETTING: Uppsala County in central Sweden. SUBJECTS: One hundred and eighty-four women aged 30-77 y, with FFQ and complete DR; 73 women with subcutaneous adipose tissue (AT) samples. METHODS: Fat intake from the FFQ was calculated with/without use of qualitative information and compared to DR and fat composition of AT. MAIN OUTCOME MEASURES: Estimates of long-time intake of total fat, saturated, monounsaturated, polyunsaturated fat and ten specific fatty acids based on FFQ, DR and composition of AT. RESULTS: Mean absolute fat intake estimates based on FFQ (without vs with use of additional fat information) were 21.2 vs 20.2 g/d for saturated, 17.1 vs 16.0 g/d for monounsaturated and 7.3 vs 7.3 g/d for polyunsaturated fat. The Pearson correlation coefficient between the FFQ and AT for polyunsaturated fat was 0.65 vs 0.67. Corresponding correlation between the FFQ and DR was 0.40 vs 0.41; adjustment for energy intake increased this correlation from 0.40 to 0.52. CONCLUSIONS: The increase in the validity of fat estimates due to use of qualitative information about fat was negligible; energy adjustment had greater impact than asking additional questions.

A prospective study of association of monounsaturated fat and other types of fat with risk of breast cancer.

BACKGROUND: Animal studies suggest that monounsaturated and polyunsaturated fat may have opposite effects on the risk of breast cancer. METHODS: We performed a population-based prospective cohort study, including 61,471 women aged 40 to 76 years from 2 counties in central Sweden who did not have any previous diagnosis of cancer; 674 cases of invasive breast cancer occurred during an average follow-up of 4.2 years. All subjects answered a validated 67-item food frequency questionnaire at baseline. Cox proportional hazards models were used to obtain adjusted rate ratio (RR) estimates with 95% confidence intervals (CIs). RESULTS: After mutual adjustment of different types of fat, an inverse association with monounsaturated fat and a positive association with polyunsaturated fat were found. The RR for each 10-g increment in daily intake of monounsaturated fat was 0.45 (95% CI, 0.22-0.95), whereas the RR for a 5-g increment of polyunsaturated fat was 1.69 (95% CI, 1.02-2.78); the increments correspond to approximately 2 SDs of intake in the population. Comparing the highest quartile of intake with the lowest, we found an RR of 0.8 (95% CI, 0.5-1.2) for monounsaturated fat and 1.2 (95% CI, 0.9-1.6) for polyunsaturated fat. Saturated fat was not associated with the risk of breast cancer. CONCLUSIONS: Our results indicate that various types of fat may have specific opposite effects on the risk of breast cancer that closely resemble the corresponding effects in experimental animals. Research investigations and health policy considerations should take into account the emerging evidence that monounsaturated fat might be protective for risk of breast cancer.