Table 2.

Log blood harmane concentration and coffee consumption in analyses stratified by case-control status.

	ET cases (N = 242)	Controls (N = 255)
Log blood harmane concentration (g−10/ml)
Drank coffee on morning of phlebotomy	0.42 ± 0.54 [0.34]	0.37 ± 0.62 [0.28]
Did not drink coffee	0.56 ± 0.57 [0.42]	0.40 ± 0.65 [0.26]
	P = .11a	P = .69a
Correlation between the number of cups of coffee on morning of phlebotomy and log blood harmane concentration	r = −0.012, P = .068	r = −0.002, P = .97
Correlation between the number of cups of coffee on morning of phlebotomy and log blood harmane concentration (in 214 participants who drank coffee on the morning of phlebotomy)	r = −0.014, P = .23	r = 0.078, P = .38

^aMann Whitney test. In upper row, values are means ± standard deviation (median). Correlation coefficients, r, are Spearman's rho.