Abstract
We used design principles of target trial methodology to emulate the effect of sustained adherence to the Dietary Approaches to Stop Hypertension (DASH) diet on the 22-year risk of heart failure. Women and men aged 45-83 years without previous heart failure, who answered questionnaires in 1997 from the Swedish Mammography Cohort and the Cohort of Swedish Men, were eligible. Follow-up questionnaires were sent in 2008-2009. Incidence of heart failure was ascertained using the Swedish Patient Register, updated until December 31, 2019. The parametric g-formula was used to estimate the 22-year risk of heart failure under sustained adherence to a population-adapted DASH diet compared with no intervention. Intakes before 1997 for before-baseline adjustment was available only for women. In total, 31,238 women and 34,939 men were eligible. The 22-year risk of heart failure was 14.5% with long-term adherence to the DASH diet compared with 15.2% with no intervention (risk difference = -0.7%, 95% confidence interval: 1.6, 0.0%) in women and correspondingly in men 15.3% vs. 16.2% (risk difference = -0.9%, 95% confidence interval: -1.6, -0.2%). Our hypothetical intervention suggests that sustained adherence to the population-adapted DASH diet may reduce risk of heart failure in middle-aged and elderly Swedish women and men.