Table 3. Genotype distribution of CLOCK 3111T/C according to Morningness/Eveningness characteristics.

	Time of the day feeling best							Time of the day with high mental performance
	Morning		Evening			Feeling best in the morning		Morning		Evening			Morning mental performance
CLOCK 3111T/C	n	%	n	%	P value	OR (95% CI)	P value	n	%	n	%	P value	OR (95% CI)	P value
CC+TC	225	43	109	53	0.007	0.684(0.491–0.953)	0.024	276	44	58	54	0.028	0.664(0.440–1.00)	0.049
TT	301	57	96	47				351	56	49	45

ORs were calculated for combined groups of minor allele carriers (CC+TC) compared with TT subjects. Adjusted for sex, age and study site.