Baseline characteristics of the What Comes Next Cohort at the time of genetic testing
| Characteristic | No. (%) of participants* n = 15 986 |
|---|---|
| Age, yr, mean ± SD | 52.5 ± 13.9 |
| Ethnicity† | |
| European | 10 130 (63.4) |
| Southeast Asian | 1048 (6.6) |
| Central/South Asian or Middle Eastern | 1282 (8.0) |
| African/Caribbean | 606 (3.8) |
| Latin/Hispanic | 495 (3.1) |
| Other | 1107 (6.9) |
| Unknown | 1378 (8.6) |
| Ashkenazi Jewish | 2946 (18.4) |
| Neighbourhood income‡ | |
| Rural | 1340 (8.4) |
| Urban, lowest quintile | 1940 (12.1) |
| Urban, second quintile | 2378 (14.9) |
| Urban, third quintile | 2522 (15.8) |
| Urban, fourth quintile | 3298 (20.6) |
| Urban, highest quintile | 4481 (28.0) |
| Marginalization summary score,§ mean ± SD | 3.03 ± 0.77 |
| ADGs | |
| 0–5 | 2938 (18.4) |
| 6–7 | 3051 (19.1) |
| 8–10 | 4714 (29.5) |
| ≥ 11 | 5283 (33.0) |
| Biological children | |
| Yes | 11 702 (73.2) |
| No | 2411 (15.1) |
| Unknown | 1873 (11.7) |
| Year of testing | |
| 2007–2009 | 2793 (17.5) |
| 2010–2012 | 4616 (28.9) |
| 2013–2016 | 8577 (53.7) |
| Test type¶ | |
| Founder testing | 2072 (13.0) |
| Predictive testing | 2329 (14.6) |
| Complete analysis | 11 585 (72.5) |
| Test result | |
| Positive | 2033 (12.7) |
| Variant of uncertain significance | 1175 (7.4) |
| Negative | 11 437 (71.5) |
| Predictive negative | 1341 (8.4) |
Note: ADG = Aggregated Diagnosis Group, SD = standard deviation.
↵* Except where indicated otherwise.
↵† Women could belong to more than 1 ethnic group; also, ethnicity and Ashkenazi Jewish ancestry are not mutually exclusive.
↵‡ Data missing for 27 participants.
↵§ Each of the 4 domains of the Ontario Marginalization Index is broken down into quintiles (1 = least marginalized, 5 = most marginalized). The marginalization summary score is the average score across the 4 domains comprising the marginalization index, where 1 = low levels of marginalization and 5 = high levels of marginalization.
↵¶ Founder testing refers to testing for 3 variants carried in highest frequency among the Ashkenazi Jewish population (BRCA1 c.68_69delAG, BRCA1 c.5266dupC and BRCA2 c.5946delT). Predictive testing refers to familial testing for a specific risk-increasing variant known to be carried by a family member of the individual being tested. Complete analysis refers to sequencing of coding regions and splice sites using Sanger sequencing, next-generation sequencing or analysis by denaturing high-performance liquid chromatography, and detection of deletion or duplication by multiplex ligation-dependent probe amplification.