Omega-3 supplementation reduces cardiovascular events in women

This study pooled data from 18 large clinical trials (134,144 people total) and found that omega-3 supplements modestly reduced heart attacks, cardiovascular deaths, and the need for heart procedures. However, this finding cannot be trusted as evidence specifically about women, because the study never analyzed women separately.

• The effect sizes are small and close to no effect: the risk reductions were 10% for revascularization (RR 0.90), 11% for heart attacks (RR 0.89), and 8% for cardiovascular death (RR 0.92) — all with upper confidence intervals near 1.0, meaning the true benefit could be very small
• Women made up anywhere from 0% to 69% of participants across the different trials, but results were never broken down by sex
• The overall benefit observed applies to a predominantly mixed or male-majority population, not specifically to women
• The significant results for heart attacks and cardiovascular death disappeared when one or two influential trials were removed, suggesting the findings are not fully robust
• One of the authors' institutions received a research grant from Amarin, the company that makes the EPA supplement shown to have the greatest benefit — this relationship is worth noting even though the grant was not paid directly to the researchers