Table 1. Overview of the two DNA methylation data sets.

	Caucasian (Data Set 1)			Hispanic (Data Set 2)
	P-value	PD	control	P-value	PD	control
Sample size		289	219		46	38
No. Female	0.47	125	102	0.05	14	20
Smoking Status	0.013			0.21
Smoking: current		15	13		3	4
Smoking: former		120	118		21	6
Smoking: never		154	88		22	8
	P-value	mean (SE), min, max	mean (SE), min, max	P-value	mean (SE), min, max	mean (SE), min, max
Smoking: total pack years	0.0051	11.4 (1.3),0,175	14.8 (1.6),0,125	0.65	5.7 (2),0,73	7 (2.9),0,39
Age	0.053	71 (0.6),37,91	68 (0.8),35,92	0.60	67.3 (1.6),37,83	65 (2.1),36,86
Year Born	0.14	1932 (0.6),1915,1966	1935 (0.8),1912,1969	0.27	1938 (2),1920,1964	1944 (4),1918,1969
Education: no. of years in school	0.0085	14.1 (0.2),6,30	14.8 (0.2),5,27	0.16	9.6 (0.72),0,20	11.2 (1),1,19
PD Family History	0.16	0.15 (0.021),0,1	0.11 (0.021),0,1	0.30	0.15 (0.05),0,1	0.6 (0.056),0,1
Caffeinated Coffee: lifetime weighted ave. (cup/day)	0.21	1.8 (0.12),0,14	2.2 (0.18),0,19	0.54	1.6 (0.48),0,20	1.3 (0.29),0,4
Organophospate count (residential+occuputation)	2.8×10–8	9 (0.59),0,46	4.9 (0.47),0,41	1.7×10–3	13.3 (1.63),0,37	5.9 (2.4),0,30
Year diagnosed with PD		2001 (0.3),1998,2007			2002 (0.3),1998,2006
Levodopa Medication status		0.7 (0.03)			0.67 (0.v07)
Levodopa mg/day		350 (16),0,2300			369 (41),0,1020

Data sets 1 and 2 are comprised of Caucasians (non-Hispanic whites) and Hispanics, respectively. The p-value resulted from relating the respective variables to PD status using a non-parametric group comparison test (Kruskal Wallis test) or Fisher's exact test (for categorical variables).