From: The concentration of three anti-seizure medications in hair: the effects of hair color, controlling for dose and age
Hair Color (N)
Mean Concentration PHT (S.D.)
Estimated Means1, PHT (S.E.)
Black (24)
16.35 (5.79)
15.184 (0.58)
Brown (18)
16.76 (7.68)
15.02 (0.67)
Blond (8)
7.91 (2.92)
11.96 (1.11)
Gray (10)
6.55 (4.82)
9.23 (1.09)