Table 1.

Comparison of age and sex for those who did or did not participate in the CoBalT study

	Participants n = 2909			Non-participants n = 7720

	n^{^a}	Mean	SD	n^a	Mean	SD	P-value

Age	2746	48.2	13.5	7375	47.8	13.6	0.129

	n^{^a}	n	%	n^{^a}	n	%

Sex (female)	2821	2020	71.6	7580	5166	68.2	<0.001

↵a Data on age and sex were not available for all.