Butter, margarine and all-cause mortality or survival.

Butter: Data about high vs low consumption of butter was provided by 2 cohorts. A significant protective effect was found in one cohort among women only (19), but no association was found in the other cohort (12).
Margarine: Data about high vs low consumption of margarine was provided by 1 cohort (19). A significant protective effect was found among women only.
Butter vs margarine: Data comparing butter to margarine consumption was provided by 3 cohorts. In one cohort, HR's for butter and margarine were similar (19). In the other cohorts, no differences in effect were found for butter as opposed to margarine consumption (8, 10).

Conclusion: Few associations were found. Effects of butter and margarine consumption on mortality were similar.