Saturated fatty acids and total and CVD mortality in Norway: a prospective cohort study with up to 45 years of follow-up.

Abstract

The contribution of dietary saturated fatty acids (SFA) to cardiovascular disease (CVD) and mortality remains debated after decades of research. Few previous studies had repeated dietary assessments and power to assess mortality. Evidence for individual SFA is limited. In this large population-based cohort study, we investigated associations between intake of total and individual SFA and risk of total and CVD mortality. Adult residents (mean 41·1 years at baseline) in three Norwegian counties were invited to repeated health screenings between 1974 and 1988 (> 80 % attendance). We calculated cumulative average intakes of macronutrients from semi-quantitative FFQ. Median (interquartile range) intake of SFA was 14·6 % (12·8-16·6 %) of total energy (E%). Hazard ratios (HR) and 95 % CI were estimated using multivariable Cox regression models to assess total, CVD, ischaemic heart disease (IHD) and acute myocardial infarction (AMI) mortality. Among 78725 participants, 28555 deaths occurred during a median follow-up of 33·5 years, with 9318 deaths due to CVD. Higher intake of SFA (replacing carbohydrates) was positively associated with all mortality endpoints, including total (HR per 5 E% increment, 1·18; 95 % CI 1·13, 1·23) and CVD mortality (1·16; 95 % CI 1·07, 1·25). Theoretical isoenergetic substitution of SFA with carbohydrates or MUFA was associated with lower risk. Of individual SFA, myristic (14:0) and palmitic acid (16:0) were positively associated with mortality. In summary, dietary SFA intake was strongly associated with higher total and CVD mortality in this long-term cohort study. This supports policies implemented to reduce SFA consumption in favour of carbohydrates and unsaturated fats.