Adipose tissue fatty acids, it has been proposed, reflect dietary intake. Using data from a validation study preceding a prospective study on diet, cancer, and health in Denmark, we were able to compare fatty acid profiles in adipose tissue biopsies from 86 individuals (23 men and 63 women) aged 40-64 y and dietary intake of fatty acids (as percentage of total fat) assessed by two 7-d weighed-diet records or by a semi-quantitative food frequency questionnaire. Correlation coefficients (Pearson r) between fatty acid concentrations in adipose tissue biopsies (as percentage of total peak area) and dietary intake of fatty acid (percentage of total fat), determined from the diet records for men and women, respectively, were as follows: polyunsaturated fatty acids r = 0.74 and r = 0.46; n - 3 fatty acids of marine origin: eicosapentaenoic acid r = 0.15 and r = 0.61, and docosahexaenoic acid r = 0.47 and r = 0.57. Correlation coefficients obtained by using the food frequency questionnaire were slightly lower for most fatty acids.
Several large epidemiological studies in the Nordic countries have failed to confirm an association between age at first birth and breast cancer independent of parity. To assess whether lack of power or heterogeneity between the countries could explain this, a meta-analysis was performed of 8 population-based studies (3 cohort and 5 case-control) of breast cancer and reproductive variables in the Nordic countries, including a total of 5,568 cases. It confirmed that low parity and late age at first birth are significant and independent determinants of breast-cancer risk. Nulliparity was associated with a 30% increase in risk compared with parous women, and for every 2 births, the risk was reduced by about 16%. There was a significant trend of increasing risk with increasing age at first birth, women giving first birth after the age of 35 years having a 40% increased risk compared to those with a first birth before the age of 20 years. Tests for heterogeneity between studies were not significant for any of the examined variables. In the absence of bias, this suggests that several individual Nordic studies may have had too little power to detect the weak effect of age at first birth observed in the meta-analysis.
The influence of alcohol consumption on breast cancer risk was evaluated in a population-based case-control study, including 1,486 cases diagnosed over a one-year (1983-84) period in Denmark. Cases were identified from the files of the nationwide clinical trial of the Danish Breast Cancer Cooperative Group and the Danish Cancer Registry. The control group was an age-stratified random sample of 1,336 women from the general population. Data on risk factors were collected by self-administered questionnaires. The association of alcohol consumption with breast cancer risk varied with age and dietary fat intake. Among women aged 50-59 years, with a fat intake in the lowest quartile, the risk of breast cancer increased with increasing consumption of alcohol. A consumption of 24 g or more per day was associated with an 18-fold increased risk compared with abstainers. For women in other age groups, alcohol consumption had no significant association with breast cancer risk.
The effect of age at first pregnancy and number of pregnancies was examined in a cohort of 14,421 women where reproductive informations were collected as part of a cervical cancer screening program. A total of 352 cases occurred in the cohort. In subgroups of women defined by age at first pregnancy the relative risk of breast cancer was lower among women who were first pregnant before 25 years of age (RR = 0.85 vs 1.20). In subgroups of women defined by parity the relative risk decreased with increasing number of pregnancies from about unity among women with 0-3 pregnancies to 0.7 among women with 6 or more pregnancies.
During the past 50 years, breast cancer incidence has increased by 2-3 % annually. Despite many years of testing for estrogen receptors (ER), evidence is scarce on breast cancer incidence by ER status. The aim of this paper was to investigate the increase in breast cancer incidence by ER status. Data were obtained from the clinical database of the Danish Breast Cancer Cooperative Group which holds nationwide data on diagnosis, including pathology, treatment, and follow-up on primary breast cancers since 1977. All Danish women
The incidence of breast cancer was determined in 1245 women who were treated surgically for breast hypertrophy in Copenhagen, Denmark, between 1943 and 1971. Breast cancer cases were identified by a linkage to the Danish Cancer Registry. The expected number of breast cancers was estimated from age and calendar-time specific incidence rates in the Danish female population. A total of 18 breast cancers developed compared to 30.28 expected, yielding a relative risk (RR) of 0.59 (95% confidence interval (CI) 0.35-0.94). The greatest risk reduction was observed ten or more years after the plastic surgery operation in women who had 600 g or more of breast tissue removed (RR = 0.27; 95% CI 0.03-0.99). This suggests that the number of potential foci are important for cancer development in the breast.
In Denmark, incidence of female breast cancer remained constant from 1943 to around 1960, whereafter a steady increase has occurred, the level today being about 50% higher than in 1960. No equivalent rise has been observed for breast cancer mortality. Influence of hormonal and dietary factors on breast cancer risk and survival was evaluated in a combined population-based case-control and follow-up study, including 2,445 women, aged less than 70 years, diagnosed with breast cancer in Denmark between 1 March 1983 and 31 August 1984, identified from the files of the nation-wide clinical trial of the Danish Breast Cancer Co-operative Group (DBCG) and the Danish Cancer Registry. The control group was an age-stratified random sample of the general female population, selected from the Central Population Register. Data on risk factors were collected by self-administered questionnaires. Clinical and pathological tumour characteristics derived from DBCG. The case-control analysis confirmed an overall increased risk of breast cancer associated with urban residence, high social status, nulliparity, early age at menarche, late age at natural menopause, hormonal replacement therapy, high dietary fat intake, and high alcohol consumption in a subgroup. It failed to detect an association with age at first childbirth, oral contraceptives, smoking, intake of vegetables, tea, coffee, and sweeteners. Survival was determined by tumour size, skin invasion, number of positive lymph nodes, and grade. There was no relation between survival and reproductive or hormonal factors, dietary variables, alcohol consumption, or smoking. However, a complex relationship may exist between survival and body mass index.
From 1958 to 1987, a total of 269 primary breast cancers were diagnosed in 261 women living in the Faroe Islands. The five-year survival was 46.7% (95% confidence interval 40.3-53.0%) and the median survival four years and three months. The incidence of breast cancer in the Faroe Islands remained constant from 1958 to 1972 after which an increase occurred. At present, one in 20 Faroe women will develop breast cancer before the age of 75 years. The time trend in breast cancer incidence is similar in the Faroe Islands and in Denmark, but the incidence is significantly lower in the Faroe Islands at a level corresponding to 2/3 of the Danish. This difference is presumed to be due to a different prevalence of risk factors for development breast cancer.