Dietary fat intake and prevention of cardiovascular disease: systematic review

Objective To assess the effect of reduction or modification of dietary fat intake on total and cardiovascular mortality and cardiovascular morbidity. Design Systematic review, Data sources Cochrane Library Medline, Embase, CAB abstracts, SIGLE, CVRCT registry and biographies were searched; trials known to experts were includ ed. Included studies Randomised controlled trials stating intention to reduce o r modify fat or cholesterol intake in healthy adult participants over at le ast six months. inclusion decisions, validity, and data extraction were dup licated. Meta-analysis (random effects methodology), meta-regression, and f unnel plots were performed. Results 27 studies (30 902 person years of observation) were included. Alte ration of dietary fat intake had small effects on total mortality (rate rat io 0.98; 95% confidence interval 0.86 to 1.12). Cardiovascular mortality wa s reduced by 9% (0.91; 0.77 to 1.07) auld cardiovascular events by 16% (0.8 4; 0.72 to 0.99), which was attenuated (0.86; 0.72 to 1.03) in a sensitivit y analysis that excluded a trial using oily fish. Trials with at least two years' follow up provided stronger evidence of protection from cardiovascul ar events (0.76; 0.65 to 0.90). Conclusions There is a small but potentially important reduction in cardiov ascular risk with reduction or modification of dietary fat intake, seen par ticularly in trials of longer duration.