Markers of dietary fat quality and fatty acid desaturation as predictors of total and cardiovascular mortality:: a population-based prospective study

Background: Desaturase indexes, as markers of endogenous fatty acid desaturation, and a characteristic serum fatty acid (FA) composition are related to cardiovascular and metabolic diseases, but the relation to mortality is poorly investigated. Objective: The objective was to evaluate the relation between dietary fat biomarkers, desaturase indexes, and mortality. Design: In this community-based prospective sample, 50-y-old men were followed for a maximum of 33.7 y. Cox proportional hazard analysis was conducted to investigate desaturase indexes (stearoyl-CoA-desaturase and Delta(6)- and Delta(5)-desaturase) and the relation of individual serum esterified fatty acids (FAs) in relation to total and cardiovascular mortality in the total study sample (n = 2009) and in a healthy subsample (n = 1885). Desaturase indexes were estimated as product-to-precursor FA ratios. Results: During follow-up, 10 12 men in the total sample died and 931 men in the healthy subsample died. Desaturase indexes predicted both total and cardiovascular mortality. The relations were independent of smoking status, physical activity, BMI, total cholesterol, and hypertension. The adjusted and standardized (per SD) hazard ratios (HRs) and 95% CIs for cardiovascular mortality were 1.15 (1.04, 1.27) for stearoyl-CoA-desaturase, 1.12 (1.0, 1.24) for Delta(6)-desaturase, and 0.88 (0.80, 0.98) for Delta(5)-desaturase, respectively. The proportion of serum linoleic acid was inversely related, whereas serum FAs associated with saturated fat intake (palmitic, palmitoleic, and dihomo-gamma-linolenic acids) were directly related to total and cardiovascular mortality. Conclusions: Altered endogenous FA desaturation might contribute to mortality risk because we observed independent associations between desaturase activity indexes and mortality. The proportion of linoleic acid was inversely related, and FAs reflecting saturated fat intake were directly related to mortality.