Table 2.

Summary of matched case-control studies on the association of hypertension with risk of Parkinson’s disease.

Study	Country	Sample size	Assessment of hypertension	OR (95% CI)	P value	Matching criteria
Current study	Singapore	671 PD, 671 controls	Questionnaire and medical record	1.86 (1.46–2.38)	<0.0001	Gender, age
Paganini-Hill17	USA	395 PD, 2320 controls	Questionnaire	0.71 (0.56–0.89)	None	Gender, age, vital status
Powers et al.16	USA	Males: 217 PD, 298 controls	Questionnaire	0.80 (0.55–1.17)	None	Gender, age, area
Becker et al.15	UK	3637 PD, 3637 controls	Medical record	0.83 (0.74–0.92)	0.001	Gender, age, general practice, index date, and duration of previous history