Figure 2.

Estimated proportion of markers retained in the transverse colon by age, obtained from a generalised linear model including interaction between disease status and age. There is no evidence of any age trend in those without diagnosed PD (green), despite the wide age range: estimated odds ratio = 1.00 (95% CI: 0.97 to 1.04) per year. In contrast, in those with PD (red), there is some evidence of an increasing age trend: estimated odds ratio = 1.03 (95% CI: 1.00 to 1.06) per year. However, the interaction between PD status and age did not reach statistical significance, indicating either insufficient sample size or a chance observation.