Adherence to the healthy Nordic food index and total and cause-specific mortality among Swedish women

Nina Roswall, Sven Sandin, Marie Löf, Guri Skeie, Anja Olsen, Hans-Olov Adami, Elisabete Weiderpass

Several healthy dietary patterns have been linked to longevity. Recently, a Nordic dietary pattern was associated with a lower overall mortality. No study has, however, investigated this dietary pattern in relation to cause-specific mortality. The aim of the present study was to examine the association between adherence to a healthy Nordic food index (consisting of wholegrain bread, oatmeal, apples/pears, root vegetables, cabbages and fish/shellfish) and overall mortality, and death by cardiovascular disease, cancer, injuries/suicide and other causes. We conducted a prospective analysis in the Swedish Women's Lifestyle and Health cohort, including 44,961 women, aged 29-49 years, who completed a food frequency questionnaire between 1991-1992, and have been followed up for mortality ever since, through Swedish registries. The median follow-up time is 21.3 years, and mortality rate ratios (MRR) were calculated using Cox Proportional Hazards Models. Compared to women with the lowest index score (0-1 points), those with the highest score (4-6 points) had an 18 % lower overall mortality (MRR 0.82; 0.71-0.93, p < 0.0004). A 1-point increment in the healthy Nordic food index was associated with a significantly lower risk of all-cause mortality: 6 % (3-9 %), cancer mortality: 5 % (1-9 %) and mortality from other causes: 16 % (8-22 %). When examining the diet components individually, only wholegrain bread and apples/pears were significantly inversely associated with all-cause mortality. We observed no effect-modification by smoking status, BMI or age at baseline. The present study encourages adherence to a healthy Nordic food index, and warrants further investigation of the strong association with non-cancer, non-cardiovascular and non-injury/suicide deaths.