Coffee consumption and overall and cause-specific mortality: the Norwegian Women and Cancer Study (NOWAC)

Coffee consumption has previously been reported to reduce overall and cause-specific mortality. We aimed to further investigate this association by coffee brewing methods and in a population with heavy coffee consumers. The information on total, filtered, instant, and boiled coffee consumption from self-administered questionnaires was available from 117,228 women in the Norwegian Women and Cancer (NOWAC) Study. We used flexible parametric survival models to calculate hazard ratios (HR) and 95% confidence intervals (CI) for all-cause, cardiovascular, and cancer mortality by total coffee consumption and brewing methods, and adjusted for smoking status, number of pack-years, age at smoking initiation, alcohol consumption, body mass index, physical activity, and duration of education. During 3.2 million person-years of follow-up, a total of 16,106 deaths occurred. Compared to light coffee consumers (≤ 1 cup/day), we found a statistically significant inverse association with high-moderate total coffee consumption (more than 4 and up to 6 cups/day, HR 0.89; 95% CI 0.83–0.94) and all-cause mortality. The adverse association between heavy filtered coffee consumption (> 6 cups/day) and all-cause mortality observed in the entire sample (HR 1.09; 95% CI 1.01–1.17) was not found in never smokers (HR 0.85; 95% CI 0.70–1.05). During the follow-up, both high-moderate total and filtered coffee consumption were inversely associated with the risk of cardiovascular mortality (HR 0.79; 95% CI 0.67–0.94; HR 0.80; 95% CI 0.67–0.94, respectively). The association was stronger in the analyses of never smokers (> 6 cups of filtered coffee/day HR 0.20; 95% CI 0.08–0.56). The consumption of more than 6 cups/day of filtered, instant, and coffee overall was found to increase the risk of cancer deaths during the follow-up. However, these associations were not statistically significant in the subgroup analyses of never smokers. The data from the NOWAC study indicate that the consumption of filtered coffee reduces the risk of cardiovascular deaths. The observed adverse association between coffee consumption and cancer mortality is most likely due to residual confounding by smoking

Seafood Intake and Serum Levels of Polychlorinated Biphenyls in Mother and Child

Background and objectives Seafood is considered a natural part of a healthy and balanced diet. Seafood is an excellent source of high quality protein, and contains many essential nutrients like omega-3 fatty acids, vitamin D, B12, iodine, and selenium. At the same time it contains some environmental contaminants, such as polychlorinated biphenyls (PCBs), which may have undesirable health effects. The risk-benefit of seafood is therefore under debate, with focus on oily fish in particular. Based on this public debate the Norwegian Directorate of Health recently advised young, as well as pregnant women, to consume no more than two meals of oily fish per week over longer periods of time. This might reduce the foetal exposure to PCBs that can have a negative effect on development. The National Institute of Nutrition and Seafood Research (NIFES) did not support this advice, as it was based on contaminant data from 2004, and contaminant levels have decreased since then. In this project mothers’ seafood intake during pregnancy and postpartum was assessed, and serum concentrations of PCBs from both mother and child have been determined. The relationship between PCB-concentrations in mother and child and reported seafood intake was then evaluated. Confounding factors for body burden of PCBs, like BMI, age, breastfeeding, and parity, were also examined to see if they had an influence on the PCB-concentrations. Method This project was part of the prospective longitudinal population-based study “Nutrition, Mental Health and Infant Development” that took place in the municipality Fjell in Western-Norway, 2010-2012. Blood was sampled from mothers in the 28th gestation week and at 3-, 6- and 12 months after birth from both mother and child. Dietary habits of mothers were assessed by a seafood-food frequency questionnaire (seafood-FFQ), and dietary habits of the children were assessed by a 24-hour recall interview and an interviewer administrated FFQ. The following PCBs: PCB-118, PCB-138, PCB-153 and PCB-180 were extracted from 100 μl serum and analysed by High Resolution Gas Chromatography – High Resolution Mass Spectrometry (HRGC-HRMS). Results and conclusion The women in this study population consumed less seafood than the amount recommend by the Norwegian Directorate of Health. All four PCBs were detected in serum from both mother and child, at levels considerably lower than other European countries. Whereas breastfeeding in itself had little impact on the serum PCB-levels in mothers, breastfed children had increased iv serum PCB-levels compered to not breastfed children. The serum PCB-levels increased with age and parity in non-breastfeeding and breastfeeding women respectively. Fish liver consumption was the only seafood that decisively had an impact on serum PCB-levels. When excluding fish liver consumers there were no relationship between maternal fish intake and serum PCB-levels in mother or child. Pregnant and young women should therefore increase their seafood intake to achieve the overall beneficial health effects, but avoid consumption of fish liver

Adherence to the Healthy Nordic Food Index in the Norwegian Women and Cancer (NOWAC) cohort

Background: High adherence to the Healthy Nordic Food Index has been associated with better health outcomes, but the results have not been consistent. The association between high adherence and higher intake of energy and healthy and less healthy foods has been persistent across countries, highlighting the need to examine potential confounding by energy intake. Objective: This study aimed to examine energy-adjusted dietary factors and lifestyle factors related to the index in a Norwegian context. Design: The study was cross-sectional within the Norwegian Women and Cancer cohort and included 81,516 women aged 41–76. Information about habitual food intake was based on a food frequency questionnaire (FFQ). The index incorporated six food groups (fish, root vegetables, cabbages, apples/pears, whole grain bread, and breakfast cereals). Ordered trend and regression analyses were performed to assess the association between the index and lifestyle and dietary factors with energy-adjusted models. Results: Nearly one out of four women (22.8%) had low adherence, 49.0% had medium adherence, and 28.2% had high adherence to the index. Intake of energy and of both healthy and less healthy foods increased with increased adherence. Energy adjustment removed the associations between less healthy foods and high adherence and demonstrated a better dietary composition in high adherers. The healthy Nordic foods contributed more to the total food intake in high versus low adherers, and high adherence was associated with a healthier lifestyle. Conclusion: High adherence was associated with a healthier lifestyle, both concerning diet and other factors. Energy adjustment of potential confounding foods removed associations between high adherence and less healthy foods. The Nordic foods accounted for a larger fraction of the diet among high adherers, at the expense of other healthy foods. Careful adjustment for confounders is warranted when assessing associations between the index and health outcomes

Coffee Consumption and Whole-Blood Gene Expression in the Norwegian Women and Cancer Post-Genome Cohort

Norwegians are the second highest consumers of coffee in the world. Lately, several studies have suggested that beneficial health effects are associated with coffee consumption. By analyzing whole-blood derived, microarray based mRNA gene expression data from 958 cancer-free women from the Norwegian Women and Cancer Post-Genome Cohort, we assessed the potential associations between coffee consumption and gene expression profiles and elucidated functional interpretation. Of the 958 women included, 132 were considered low coffee consumers (3 cups of coffee/day). At a false discovery rate <0.05, 139 genes were differentially expressed between high and low consumers of coffee. A subgroup of 298 nonsmoking, low tea consumers was established to isolate the effects of coffee from smoking and potential caffeine containing tea consumption. In this subgroup, 297 genes were found to be differentially expressed between high and low coffee consumers. Results indicate differentially expressed genes between high and low consumers of coffee with functional interpretations pointing towards a possible influence on metabolic pathways and inflammation

High lactose whey cheese consumption and risk of colorectal cancer - The Norwegian Women and Cancer Study

The incidence of colorectal cancer (CRC) has increased among Norwegian women, and is among the highest in the world. In order to understand this increase, country specific dietary exposures have been investigated. The aim of this study was to quantify the association between consumption of brown cheese, a common bread topping in Norway, and colorectal, colon, and rectal cancer in the prospective Norwegian Women and Cancer (NOWAC) Study. Data on brown cheese consumption and adjustment factors was available for 82 527 women. During a mean of 14.6 years of follow-up (1.2 million person-years), there were 1360 cases of colorectal cancer (907 colon; 453 rectal). Multivariable Cox proportional hazards models were used to calculate hazard ratios (HR) with 95% confidence intervals (CI) for colorectal, colon, and rectal cancer sites. We modelled restricted cubic splines with 4 knots, to assess a possible non-linear relationship between brown cheese intake and the investigated cancer sites. In the age-adjusted model, consumption of more than 2 slices (>16 grams) of brown cheese per day was associated with 13% reduced risk of colon cancer (95% CI 4%-21%) compared to women who did not consume brown cheese. The multivariable-adjusted model, however, showed no association between brown cheese consumption and the risk of colorectal, colon, or rectal cancer (colorectal: HR = 0.93, 95% CI 0.76–1.13, p-trend 0.37; colon: HR = 0.83, 95% CI 0.65–1.06; p-trend = 0.10; rectal: HR = 1.16, 95% CI 0.84–1.1.61, p-trend = 0.41). In this large, prospective cohort study of women, consumption of brown cheese was suggestively protective against colon cancer. However, adjustment attenuated the inverse risk association. Brown cheese consumption was not associated with rectal cancer, or colorectal cancer overall