Table 1. Characteristics of the Study Cohort at the First Eligible Routine CBC Test.
| Description | Individuals (N = 8 917 187)a |
|---|---|
| Sex | |
| Female | 4 971 578 (55.8) |
| Male | 3 945 609 (44.2) |
| Age, y | |
| Mean (SD) | 47.0 (17.8) |
| Median (IQR) | 46.4 (32.5-59.5) |
| Residence location | |
| Urban | 8 084 848 (90.7) |
| Rural | 820 419 (9.2) |
| Missing | 11 920 (0.1) |
| Core primary care visits to general practitioner or family practitioner in previous 2 y, No. | |
| Mean (SD) | 2.8 (3.4) |
| Median (IQR) | 2 (1-3) |
| Rostered to family physician | 6 940 867 (77.8) |
| Comorbidities and chronic conditions | |
| Asthma | 796 810 (8.9) |
| Congestive heart failure | 172 576 (1.9) |
| COPD | 192 482 (2.2) |
| Hypertension | 2 139 804 (24.0) |
| Diabetes | 666 477 (7.5) |
| Kidney disease | 88 520 (1.0) |
| Chronic coronary syndrome | 321 278 (3.6) |
| Hemoglobin concentration, g/L | |
| Mean (SD) | 139.5 (14.9) |
| Median (IQR) | 140 (130-150) |
| Platelet count, 109/L | |
| Mean (SD) | 247.2 (64.5) |
| Median (IQR) | 241 (205-282) |
| Observation time, yb | |
| Mean (SD) | 6.8 (3.0) |
| Median (IQR) | 7.3 (4.4-9.3) |
| Routine CBC tests in observation period, No. | |
| Mean (SD) | 4.3 (6.3) |
| Median (IQR) | 3 (1-6) |
| Cancer diagnosisb,c | |
| Any | 492 691 (5.5) |
| Solid tumor | 429 222 (4.8) |
| Colon | 51 521 (0.6) |
| Lung | 56 724 (0.6) |
| Breastd | 65 721 (1.3) |
| Ovaryd | 7661 (0.2) |
| Cervicald | 3494 (0.1) |
| Endometriald | 17 101 (0.3) |
| Prostatee | 62 946 (1.6) |
| Thyroid | 21 478 (0.2) |
| Pancreas | 12 021 (0.1) |
| Stomach | 9195 (0.1) |
| Kidney | 14 063 (0.2) |
| Bladder | 23 344 (0.3) |
| Liver | 7696 (0.1) |
| Esophagus | 4712 (0.1) |
| Other gastrointestinal tract | 5255 (0.1) |
| Brain | 5724 (0.1) |
| Melanoma | 20 192 (0.2) |
| Head and neck | 13 363 (0.1) |
| Other | 27 011 (0.3) |
| Hematologic tumor | 63 469 (0.7) |
| Leukemia | 5154 (0.1) |
| Lymphoma | 33 827 (0.4) |
| Multiple myeloma | 8274 (0.1) |
| Other | 16 214 (0.2) |
Abbreviations: CBC, complete blood count; COPD, chronic obstructive pulmonary disease; OHIP, Ontario Health Insurance Plan.
SI conversion factors: To convert hemoglobin concentration to grams per deciliter, divide by 10.0; platelet count to 103 per microliter, divide by 1.0.
a
Data are presented as number (percentage) of individuals unless otherwise indicated.
b
Period of observation was from the first eligible CBC test to the earliest date of death, end of OHIP eligibility, or end of the observation period (December 31, 2018).
c
Data are from the Ontario Cancer Registry.
d
Women only.
e
Men only.