Table I.

Racial Background of Combined United States and Australian At‐Risk and Control Samples

	All subjects (%)	At‐risk (%)	Control (%)
European	478 (78.5)	335 (91.3)	143 (62.4)
Asian	38 (6.2)	1 (0.3)	37 (16.2)
African	40 (6.6)	5 (1.4)	35 (15.3)
Mixed race/other/unknown	53 (8.7)	26 (7.0)	14 (6.1)
Total	609 (100)	367 (100)	229 (100)

The total number of individuals in each racial group (reported in line with the seven US census categories) is given, along with the percentage (%) representation within each sample. The numbers of individuals represented in the mixed race/other/unknown category were of Australian Aboriginal/Hawaiian/Pacific Islander (n = 7), American Indian/Alaska native (n = 1), mixed race (n = 18), or other/unknown (n = 27) descent.