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Objective: To determine the vitamin D status of middle-aged women living in the Norwegian arctic and its relationship with vitamin D intake and exposure to ultraviolet (UV) radiation.Design: Cross-sectional study.Subjects and Setting: This study is based on measurements of 25-hydroxyvitamin D (25(OH)D) levels in a sub-sample of the Norwegian component of the EPIC biological bank, which consists of blood samples from a random selection of participants in the Norwegian Women and Cancer Study. From November 2001 until June 2002, 309 blood samples were collected from a total of 443 invited middle-aged women (44-59 years) in northern Norway (65-71 degrees N) (crude response rate, 69.8%). Questionnaire data provided information on dietary sources of vitamin D and UV exposure.Results: Median plasma 25(OH)D concentration for the whole group was 55.0 nmol l(-1) (range 8.1-142.8 nmol l(-1)). Vitamin D intake was a significant predictor of 25(OH)D status (P=0.0003). The time of the year when the blood sample was collected significantly predicted plasma 25(OH)D level (P=0.005). Levels of 25(OH)D were positively associated (P=0.0002) with estimated hours per day of exposure to UV-B radiation. Residing in northern Norway during the summer prior to blood sampling was negatively associated with 25(OH)D concentration (P=0.001). The prevalence of moderate hypovitaminosis D was highest in January-February, when a quarter of the participants had 25(OH)D concentrations < or =37.5 nmol l(-1).Conclusions: Increased ingestion of marine food items that provide vitamin D should be promoted and further studies should be carried out to investigate vitamin D status in arctic populations in relation to both UV exposure and traditional food sources. [ABSTRACT FROM AUTHOR]

Abstract Background Pregnancy-related pelvic pain is a common condition, and use of hormonal contraceptives before pregnancy has been proposed as a risk factor. We used data from a sub-sample of women participating in the "Norwegian Women and Cancer study" (NOWAC) to assess the association between hormonal contraceptive use and pelvic pain in pregnancy. Methods From a sub-group of 2078 parous women participating in the NOWAC study, information was collected from a self-instructive four-page questionnaire containing questions about lifestyle and medical conditions. We calculated odds ratios (OR) and 95% confidence intervals (CI), using unconditional logistic regression. Results In this study, the prevalence of pelvic pain in women was 26.5% during the first pregnancy and increased with parity. Use of hormonal contraceptives before a woman's first pregnancy was associated with an increased risk of pelvic pain in her first pregnancy (OR = 1.6; 95% confidence interval 1.2–2.2). There was no association between use of hormonal contraceptives and pelvic pain in the second or third pregnancy. Occurrence of pelvic pain in a previous pregnancy was the only factor associated with pelvic pain in subsequent pregnancies (OR = 51.1; 95% CI 32.9–79.5 in the second pregnancy and OR = 28.3; 95% CI 15.4–53.1 in the third pregnancy). Conclusion Use of hormonal contraceptives was associated with an increased risk of pelvic pain in a woman's first pregnancy. The most important determinant of pelvic pain in the second or third pregnancy was the history of pelvic pain in the preceding pregnancy.

This is an update of the Norwegian Mother and Child Cohort Study (MoBa) cohort profile which was published in 2006. Pregnant women attending a routine ultrasound examination were initially invited. The first child was born in October 1999 and the last in July 2009. The participation rate was 41%. The cohort includes more than 114 000 children, 95 000 mothers and 75 000 fathers. About 1900 pairs of twins have been born. There are approximately 16 400 women who participate with more than one pregnancy. Blood samples were obtained from both parents during pregnancy and from mothers and children (umbilical cord) after birth. Samples of DNA, RNA, whole blood, plasma and urine are stored in a biobank. During pregnancy, the mother responded to three questionnaires and the father to one. After birth, questionnaires were sent out when the child was 6 months, 18 months and 3 years old. Several sub-projects have selected participants for in-depth clinical assessment and exposure measures. The purpose of this update is to explain and describe new additions to the data collection, including questionnaires at 5, 7, 8 and 13 years as well as linkages to health registries, and to point to some findings and new areas of research. Further information can be found at [www.fhi.no/moba-en]. Researchers interested in collaboration and access to the data can complete an electronic application available on the MoBa website above., (© The Author 2016; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association.)

There is current interest in fish consumption and marine omega-3 (n-3) fatty acids and breast cancer risk. Some in vitro and animal studies have suggested an inhibitory effect of marine n-3 fatty acids on breast cancer growth, but the results from epidemiological studies that have examined the association between fish consumption and breast cancer risk in humans are inconsistent. We examined fish consumption and breast cancer risk in 310,671 women aged between 25 and 70 yr at recruitment into the European Prospective Investigation Into Cancer and Nutrition (EPIC). The participants completed a dietary questionnaire between 1992-98 and were followed up for incidence of breast cancer for a median of 6.4 yr. Hazard ratio for breast cancer by intake of total and lean and fatty fish were estimated, stratified by study centre and adjusted for established breast cancer risk factors. During follow-up, 4,776 invasive incident breast cancers were reported. No significant associations between intake of total fish and breast cancer risk were observed, hazard ratio (HR) 1.01 (95% confidence interval [CI] 0.99-1.02; p = 0.28 per 10 g fish/day). When examining lean and fatty fish separately, we found a positive significant association only in the highest quintile for fatty fish (HR 1.13, 95% CI 1.01-1.26), but test for trend was not significant (p = 0.10). No associations with breast cancer risk were observed when the study participants were subdivided by menopausal status. Although the period of follow-up is relatively short, the results provide no evidence for an association between fish intake and breast cancer risk.

Background: Sales of HRT in Norway have increased considerably over the last 10 to 15 years, as has the incidence of breast cancer. The aim of this study was to investigate the relationship between use of HRT and risk of breast cancer in a Norwegian cohort of women., Material and Methods: The Norwegian Women and Cancer (NOWAC) study is a representative, national, population-based cohort study involving 31,451 postmenopausal women aged 45-64 who contributed information on reproduction, lifestyle and use of HRT. The women are followed up for breast cancer., Results: Current users of HRT, 35% of those included, had an adjusted relative risk of breast cancer of 2.1 (95% CI 1.5-2.5). A continuous regimen of estrogen/progestagen implied an increased risk compared to a sequential regimen. Longer use increased the risk (test for trend p<0.0001). The population-attributable risk of breast cancer due to use of HRT was estimated at 27%, which equals approximately 300 cases of breast cancer per year among Norwegian women aged 45-64., Interpretation: Our results suggest that current use of HRT could be considered a major determinant of the increasing incidence of breast cancer in postmenopausal women in Norway. Treatment should, accordingly, be restricted to women with serious vasomotor complaints. The dosage should be individually tailored according to potential risks and benefits, and treatment given over a short period of time.

Context: The intake of vegetables and fruits has been thought to protect against breast cancer. Most of the evidence comes from case-control studies, but a recent pooled analysis of the relatively few published cohort studies suggests no significantly reduced breast cancer risk is associated with vegetable and fruit consumption., Objective: To examine the relation between total and specific vegetable and fruit intake and the incidence of breast cancer., Design, Setting, and Participants: Prospective study of 285,526 women between the ages of 25 and 70 years, participating in the European Prospective Investigation Into Cancer and Nutrition (EPIC) study, recruited from 8 of the 10 participating European countries. Participants completed a dietary questionnaire in 1992-1998 and were followed up for incidence of cancer until 2002., Main Outcome Measures: Relative risks for breast cancer by total and specific vegetable and fruit intake. Analyses were stratified by age at recruitment and study center. Relative risks were adjusted for established breast cancer risk factors., Results: During 1,486,402 person-years (median duration of follow-up, 5.4 years), 3659 invasive incident breast cancer cases were reported. No significant associations between vegetable or fruit intake and breast cancer risk were observed. Relative risks for the highest vs the lowest quintile were 0.98 (95% confidence interval [CI], 0.84-1.14) for total vegetables, 1.09 (95% CI , 0.94-1.25) for total fruit, and 1.05 (95% CI , 0.92-1.20) for fruit and vegetable juices. For 6 specific vegetable subgroups no associations with breast cancer risk were observed either., Conclusion: Although the period of follow-up is limited for now, the results suggest that total or specific vegetable and fruit intake is not associated with risk for breast cancer.

Increasing use of HRT over the last 2 decades could have contributed to the increasing incidence of cancer in women. Our aim was to investigate the relation between use of HRT and risk of hormone-dependent cancers in a Norwegian cohort of women. The Norwegian Women and Cancer (NOWAC) study is a representative, national, population-based cohort study. This report includes 35,456 postmenopausal women aged 45-64 years who answered a postal questionnaire in 1996-1998 providing information on reproduction, lifestyle and use of HRT. The women were followed up for cancer incidence. The main analyses were restricted to 31,451 postmenopausal women with complete information. Ever use of HRT was reported by 43.5% and current use, by 35% of the women. Current users had an increased risk of breast cancer (adjusted RR=2.1, 95% CI 1.5-2.5). The risk increased with increasing duration of use (ptrend < 0.0001). Using a regimen of continuous estrogen-progestagen implied an increased risk. Adjusted RRs associated with <5 and > or =5 years' duration of use were 2.6 (95% CI 1.9-3.7) and 3.2 (95% CI 2.2-4.6), respectively. The population-attributable risk of breast cancer due to current use of HRT was 27%. We found no significant increase in risk of ovarian cancer. Neither did we find users of estrogen-progestagen preparations to have any increase in risk of endometrial cancer. Our results suggest that HRT could be considered a major determinant for the increasing incidence of breast cancer in Norway.

The aim of our study was to examine the risk of breast cancer according to specific types of estrogens and progestagens in oral contraceptives (OCs) based on the prospective Norwegian Women and Cancer study (NOWAC). Between 1991-97 women aged 30-70 years were drawn at random from the central person register and mailed an invitation and a questionnaire. Women (102,443) were enrolled with follow-up information collected throughout 1999 by linkage with national registries of cancer, mortality and emigration based on the unique national identification number. Among the 96,362 women included in the present analysis 851 invasive breast cancer were diagnosed. The adjusted risk of breast cancer increased with 25% for ever use of OCs and the risk increased with increasing duration of use (test for trend: p = 0.007). No association between time since last use and breast cancer risk was found after stratification on duration of use. Positive trend was still found for total duration of use among women who used OCs more than 5 years ago. Second generation of OCs had an increased risk with increasing duration of use. Classifying progestagens according to chemical groups, the relative risk increased significantly with increasing cumulative dose of levonorgestrel progestagen. It was difficult to conclude for the other groups due to lack of power. In a multivariate analysis the cumulative dose for all progestagen groups were non-significant, although we observed a significant increased risk with increasing milligram-months of estrogen exposure (p = 0.002). In conclusion, the increased risk of breast cancer related with OC formulations could be due mostly to estrogen component., (Copyright 2003 Wiley-Liss, Inc.)

Background: Use of oral contraceptives and the risk of cancer continues to be an issue., Material and Methods: The Norwegian Women and Cancer Cohort Study was initiated in order to study the use of oral contraceptives and risk of cancer. A total of 102 443 women aged 31-70 were included from 1991 to 1997. In the follow-up analysis through 1999, 851 of the 96 355 eligible women had developed breast cancer, 171 ovarian cancer, 118 cervical cancer, 110 endometrial cancer and 219 colorectal cancer., Results: The risk of breast cancer increased with the duration of oral contraceptive use (p for trend p = 0.002), while risk of ovarian and endometrial cancer decreased (p for trend p = 0.03 for endometrial cancer and p < 0.0001 for ovarian cancer). No significant association between the use of oral contraceptives and the combined risk of breast/endometrial/ovarian cancer was revealed., Interpretation: Use of oral contraceptives does not seem to change the overall risk of cancer. The increased risk of breast cancer is compensated by the protective effect in relation to endometrial and ovarian cancer.