On the other hand, significant risk reductions were observed for people with no history of hypertension, and ‘meaningful’ decreases were also seen in people with no history of CVD, report investigators of the AREDS2 Research Group.
“There was a numerical but not statistically significant difference toward heterogeneity in effects in the participants receiving omega-3 fatty acids, with those having no history of CVD or at low risk for development of the disease (no CVD, no hypertension, no elevated cholesterol level) showing potential benefit and those with a history of CVD or at higher risk of CVD showing no effect,” they wrote.
“However, the number of events for these subgroups was small, the confidence interval was wide, and the lack of isolated, individual risk factors may not provide a complete picture of an individual’s total cardiovascular risk.”
Leading supplement experts have questioned the cut-off levels in the study to show statistical significance, with the ‘meaningful’ but non-statistically significant results for omega-3s still having potentially important clinical benefits, despite the overall null results.
‘A failure to detect an effect’
Harry Rice, PhD, VP of regulatory & scientific affairs at the Global Organization for EPA and DHA Omega-3s (GOED), told NutraIngredients-USA: “Given that this ancillary study was under-powered, the results are not surprising and should not be misinterpreted as a lack of an effect(s), rather a failure to detect an effect. Prespecified subgroup analyses revealed some interesting protective effects - significant among individuals without a history of hypertension, as well as a trend among those without a history of cardiovascular disease.”
Duffy MacKay, ND, Sr VP of scientific & regulatory affairs for the Council for Responsible Nutrition (CRN), told us that the study was set up so that a positive result – ie. statistically significant – was associated with a 25% reduction in CVD events. “A 25% risk reduction to obtain a positive study is huge. These are drug-like numbers,” he added.
Despite the headline conclusion of the paper, “we did see great results in here”, he said.
Indeed, there was a statistically significant 34% reduction in risk of CVD in people with no history of hypertension, and a non-significant 19% reduction for people with no history of CVD. “That may not be statistically significant but it is still meaningful,” said Dr MacKay. “In these pre-defined sub-populations we see real demonstrable benefits.”