Demographic characteristics of respondents
| ALS | n (%) | Control | n (%) |
| Country of birth | |||
| USA | 72 (36) | Australia | 228 (62) |
| Australia | 55 (27) | Other (<3% each) | 65 (18) |
| Canada | 32 (16) | USA | 33 (9) |
| Other (<3% each) | 22 (11) | UK | 23 (6) |
| UK | 11 (5) | South Africa | 10 (3) |
| South Africa | 5 (3) | Spain | 10 (3) |
| Spain | 5 (3) | ||
| Country of residence | |||
| USA | 73 (36) | Australia | 282 (76) |
| Australia | 69 (34) | USA | 39 (11) |
| Canada | 38 (19) | Other* (<1% each) | 27 (7) |
| Other* (<3% each) | 12 (6) | Canada | 5 (1) |
| South Africa | 5 (3) | New Zealand | 5 (1) |
| Spain | 5 (3) | ||
| Ancestry | |||
| Other (<6% each) | 82 (41) | Other (<4% each) | 125 (34%) |
| Australian | 34 (17) | Australian | 105 (28) |
| English | 28 (14) | English | 66 (18) |
| American | 16 (8) | Irish | 35 (10) |
| Irish | 16 (8) | British | 20 (5) |
| Canadian | 13 (6) | Scottish | 15 (4) |
| German | 13 (6) | ||
| Cultural group | |||
| Australian | 57 (28) | Australian | 238 (64) |
| American | 43 (21) | Other (<2% each) | 63 (17) |
| Other (<3% each) | 43 (21) | American | 24 (7) |
| Canadian | 29 (14) | English | 22 (6) |
| English | 17 (8) | Spanish | 10 (3) |
| German | 6 (3) | Dutch | 8 (2) |
*Other countries of residence (in alphabetical order): Argentina, Belgium, Brazil, China, Colombia, Denmark, Ecuador, Egypt, Finland, Germany, Iran, Ireland, Italy, Japan, Lebanon, Luxembourg, Mexico, the Netherlands, Portugal, Russia, Slovakia, South Korea, Sweden, Switzerland, Turkey and UK.
Some subsets do not add up to the total number of respondents because of answers to particular questions not being given.
ALS, amyotrophic lateral sclerosis.