Table 4.

Critical appraisal skills programme checklist for cohort studies.

Report citation	Groups comparable	Cases and controls matched	Same criteria used for identification of cases and controls	Exposure (physical activity) is measured in a standard, valid and reliable way	Exposure measured in the same way for cases and controls	Confounding factors identified	Strategies used to deal with confounding factors	Outcomes (non-motor symptoms) assessed in a standard, valid and reliable way for cases and controls	Exposure period of interest was long enough to be meaningful	Appropriate statistical analyses used	Total score
Amara et al. (2019) 47	Y	U	Y	N	Y	Y	Y	Y	Y	Y	80%*

Abbreviations: Y = yes; N = no; U = unclear. Identification of confounding factors was rated ‘Y’ if typical confounders, such as age, gender, Levodopa dosage equivalent, disease duration, and motor symptom severity, were identified and measured. The use of valid and reliable measures was rated ‘Y’ if psychometric properties have been previously evaluated and shown acceptable levels in people with Parkinson's disease. Study quality is defined as follows: a total score greater than 70% as high quality, a score between 50% and 70% as medium quality, and a score less than 50% as low quality. *High quality articles, >70%.