Table 2.

Effect of gender on caffeine level, absorption, and metabolism.

Whole group	Male	Female	p values
Number	94	75
Basal caffeine level	1.42 ± 1.51	1.68 ± 1.98	0.51
Caffeine absorption	0.46 ± 1.42	0.64 ± 2.04	0.21
CYP1A2 activity	0.27 ± 0.23	0.29 ± 0.31	1.00

Early PD and age-matched HS	Male	Female	p values
Number	40	37
Basal caffeine level	1.32 ± 1.61	1.61 ± 1.85	0.64
Caffeine absorption	0.41 ± 1.33	0.90 ± 1.79	0.50
CYP1A2 activity	0.25 ± 0.22	0.34 ± 0.40	0.25

Moderate/advanced PD and age-matched HS	Male	Female	p values
Number	54	38
Basal caffeine level	1.49 ± 1.45	1.77 ± 2.10	0.63
Caffeine absorption	0.50 ± 1.50	0.41 ± 2.28	0.23
CYP1A2 activity	0.28 ± 0.25	0.22 ± 0.17	0.26