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

Abstract

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.

Coffee – the Wonder

“…Some other studies concomitantly examine the risk of coffee on cancer and CV cardiovascular risk (7,8). Both studies cited here conclude that the final result is positive: the Norwegian one (7) addresses 117,228 women, while the other one (8) concludes that "there is highly suggestive evidence for an inverse association between coffee intake and risk of liver and endometrial cancer". For other sites, new analyses are necessary.…”

Association of beverage consumption with subclinical atherosclerosis in a Spanish working population

“…Indeed, consumption of unfiltered boiled coffee was associated with unfavourable changes in the lipid profile, and may cause a slight but significant rise in systolic blood pressure [37][38][39] . These unfavourable associations were mitigated with filtered coffee consumption, which is associated with a reduction of cardiovascular and general mortality, when compared to unfiltered coffee 40,41 . Table 3.…”

Online education model on coffee addiction on the prevention of diabetes mellitus

“…Specific genetic polymorphisms associated with caffeine metabolism raise the risk of cardiovascular disease among coffee drinkers. In another study conducted by (Lukic et al, 2020), drinking coffee > 6 cups of filtered coffee/day filtered and instant coffee was found to increase the risk of death from cancer (HR 0,20; 95% CI: 0,08-0,56).…”