Assessing causality between osteoarthritis with urate levels and gout: a bidirectional Mendelian randomization study

Area of Science:

• Genetics and Epidemiology
• Rheumatology
• Metabolic Disorders

Background:

• The relationship between osteoarthritis (OA), serum urate levels, and gout is complex and not fully understood.
• Previous observational studies suggest associations, but causality remains unclear.

Purpose of the Study:

• To investigate the bidirectional causal relationship between osteoarthritis (OA) and urate levels, as well as gout, using Mendelian randomization (MR).

Main Methods:

• Utilized large-scale summary statistics from genome-wide association studies for OA (up to 826,690 participants), serum urate levels (288,649 participants), and gout (69,374 participants).
• Employed established MR analytical methods, including Wald ratio, inverse variance weighted (IVW), weighted median (WM), and MR-Egger regression.

Main Results:

• Genetically determined urate levels and gout showed no association with the risk of total OA.
• No causal effect of urate levels or gout was found on site-specific OA (knee, hip, spine, thumb, hand).
• Reverse MR analyses indicated no causal effect of total or site-specific OA on urate levels or gout.

Conclusions:

• This MR study provides robust evidence against a bidirectional causal effect between urate levels and gout on total and site-specific osteoarthritis.
• The findings suggest that OA and hyperuricemia/gout are likely independent conditions or share common underlying risk factors rather than a direct causal link.