TNF and Parkinson disease: Mendelian randomization estimates based on the 3 SNPs, using adapted IVW methodology to account for correlations between the variants, were consistent with the main results: neither PD risk (OR 0.99; 95% CI 0.91–1.08) nor age at onset (0.14 years of increase; 95% CI −0.66 to 0.93) were predicted to be affected by TNF-TNFR1 blockade, whereas anticipated effects on other inflammatory diseases were observed (table 3).