Non-adherence to established dietary guidelines associated with increased mortality: the Copenhagen General Population Study

Aims
The relevance of adherence to established dietary guidelines is repeatedly challenged. We hypothesised that non-adherence to established dietary guidelines is associated with an excess risk of cardiovascular, non-cardiovascular and all-cause mortality.

Methods
We studied 100,191 white adult Danes aged 20–100 years recruited in 2003–2015 and followed up until December 2018. During follow-up equalling 865,600 person-years, 9273 individuals died. Participants’ diets were assessed at baseline by a food frequency questionnaire focusing on key foods defining a healthy diet according to Danish dietary guidelines. Individuals were divided into five categories ranging from very high to very low adherence to dietary guidelines and studied with Cox and Fine–Gray regression models. At study inclusion, we collected demographic and lifestyle characteristics by questionnaire, made a physical examination and took a blood sample.

Results
Cardiovascular, non-cardiovascular and all-cause mortality increased gradually with increasing non-adherence to dietary guidelines. Cardiovascular mortality was 30% higher (95% confidence interval 7–57%), non-cardiovascular mortality 54% higher (32–79%) and all-cause mortality 43% higher (29–59%) in individuals with very low adherence to dietary guidelines compared with those with very high adherence after adjustments for age, sex, education, income, smoking, leisure time physical activity and alcohol intake. Mortality risk estimates were similar in all strata of adjusted variables.

Conclusion
Non-adherence to Danish food-based dietary guidelines is associated with up to 43% increased all-cause mortality in a dose–response manner. The mortality excess was seen for both cardiovascular and non-cardiovascular causes. The public has good reasons to have confidence in and to adhere to established dietary guidelines.