Do fish oil supplements raise the risk of heart disease? – Zoë Harcombe
Executive summary
* A paper generated global headlines that taking fish oil supplements might raise the risk of heart disease and strokes.
* The paper used data from the UK Biobank study for over 400,000 people. Approximately 30% of participants took fish oil supplements regularly. These people were claimed to be more likely to develop atrial fibrillation and have a stroke (from a healthy baseline).
* The risk ratio for arial fibrillation was small. The risk ratio for stroke was not statistically significant and should not have been reported as a finding.
* There were eight findings in total. One (the atrial fibrillation claim) found against supplements; the other seven found in favour of supplements. The headlines should have been “Seven times as many associations found in favour of fish oil supplements and heart disease as against.”
* The researchers needs to explain why there was one finding against and seven in favour of fish oil supplements. They made no attempt to do this.
* With clear bias in claims and without any plausible mechanism, this should be viewed as a spurious correlation and a non-sense paper.
