In the table below we have provided the demographics of those who completed the online survey and those who completed the full study (including soil, water, urine and toenail samples). The first number is the count and then the percentage is listed in parenthesis. So, for example, a total of 283 people completed the online survey (100%), but only 17.4% of those who completed the online survey are under 40 years old (51 people). Most of the respondents (37.1%) are between 40 and 65 years of age. A total of 80 people completed the full study, and 47.7% of them are also between 40 and 65 years of age.
| Characteristic | Completed online survey | Completed full study |
| Total | 283 (100) | 80 (100) |
| Age | ||
| <40 years | 51 (17.4) | 11 (13.8) |
| 40-65 years | 105 (37.1) | 35 (47.7) |
| >65 years | 92 (32.5) | 34 (42.5) |
| Missing data | 35 (12.3) | 0 (0) |
| Gender, N (%) | ||
| Male | 100 (35.3) | 28 (35.0) |
| Female | 169 (59.7) | 52 (65.0) |
| Missing data | 14 (5.0) | 0-(0) |
| Ethnicity, N (%) | ||
| Non-Hispanic | 280 (98.9) | 80 (100.0) |
| Hispanic | 3 (1.1) | 0 (0) |
| Race/ethnicity, N (%) | ||
| White/Caucasian | 273 (96.5) | 78 (97.5) |
| Other | 10 (3.5) | 2 (2.5) |
| Annual income, N (%) | ||
| <20,000 | 55 (19.4) | 18 (22.5) |
| 20,000-39,000 | 44 (15.5) | 13 (16.2) |
| 40,000-69,000 | 63 (22.3) | 17 (21.3) |
| >=70,000 | 53 (18.7) | 18 (22.5) |
| Missing data | 68 (24.0) | 14 (17.5) |
| Educational level | ||
| < High school | 24 (8.5) | 4 (5.0) |
| High school or GED | 123 (43.5) | 31 (38.7) |
| Some college | 66 (23.3) | 20 (25.0) |
| 4-year degree | 31 (11.0) | 10 (12.5) |
| Graduate degree | 37 (13.1) | 15 (18.8) |
| Other/missing data | 2 (0.7) | 0 (0) |