The obesity paradox for risk of recurrent gout attacks is explained by the absence of the direct effect, which is often measured in conventional analyses and misinterpreted as the intended total effect of interest, according to a recent study. Out of 11,816 gout-free subjects at baseline, researchers documented 408 incident gout cases, with 132 developing recurrent gout attacks over a 7-year follow-up. They found:

• The adjusted odds ratio (OR) for incident gout among obese individuals was 2.6, while that for recurrent gout attacks among gout patients was 0.98 (ie, the obesity paradox).

• These ORs correlated well with the ORs for the indirect and direct effects of obesity on risk of recurrent gout attacks (ie, 2.83 and 0.98, respectively).

• Compared with no body mass index (BMI) change, the OR of losing vs gaining >5% of baseline body mass index (BMI) was 0.61 and 1.60 for recurrent gout attacks, respectively, suggesting a dose-response association.