Characteristics of the population and associated testing
| Total no | Ever tested | Mean days to test | Median days to test | Deficiency | Mean days to B12 deficiency | Median days to B12 deficiency | |
| Gender | |||||||
| Male | 6247 (46.3%) | 2590 (41.5%) | 1037 | 785 | 81 (3.1%) | 1883 | 1921 |
| Female | 7242 (53.7%) | 3461 (47.8%) | 922 | 675 | 121 (3.5%) | 1955 | 2407 |
| Total | 13 489 (100%) | 6051 (44.9%) | 972 | 720 | 202 (3.3%) | 1926 | 2313 |
| Age | |||||||
| 18–39 | 830 (6.2%) | 292 (35.2%) | 929 | 643 | 3 (1.0%) | 2686 | 2780 |
| 40–49 | 1716 (12.7%) | 581 (33.9%) | 942 | 695 | 12 (2.1%) | 2367 | 2690 |
| 50–64 | 5828 (43.2%) | 2316 (39.7%) | 1050 | 780 | 64 (2.8%) | 2019 | 2397 |
| 65–79 | 4196 (31.1%) | 2285 (54.5%) | 952 | 723 | 99 (4.3%) | 1894 | 2076 |
| >80 | 919 (6.8%) | 577 (62.8%) | 785 | 553 | 24 (4.2%) | 1492 | 1133 |
| Total | 13 489 (100%) | 6051 (44.9%) | 972 | 720 | 202 (3.3%) | 1926 | 2313 |
| Race | |||||||
| African-American | 5409 (40.1%) | 2251 (41.6%) | 966 | 724 | 59 (2.6%) | 2132 | 2407 |
| Asian | 499 (3.7%) | 209 (41.9%) | 905 | 684 | 6 (2.9%) | 2312 | 2680 |
| Hispanic | 338 (2.5%) | 149 (44.1%) | 1184 | 791 | 6 (4.0%) | 2230 | 2500 |
| Other/unknown | 1385 (10.3%) | 573 (41.4%) | 969 | 692 | 22 (3.8%) | 1756 | 2165 |
| Caucasian | 5858 (43.4%) | 2869 (49.0%) | 970 | 723 | 109 (3.8%) | 1811 | 2040 |
| Total | 13 489 (11%) | 6051 (44.9%) | 972 | 720 | 202 (3.3%) | 1926 | 2313 |
| Confounders | |||||||
| Malabsorption disorders | 694 (5.1%) | 498 (71.8%) | 860 | 572 | 11 (2.2%) | 1864 | 2046 |
| Proton pump inhibitor use (prescriptions) | 3957 (29.3%) | 2173 (54.9%) | 947 | 703 | 70 (3.2%) | 2058 | 2452 |
| Total | 4651 (100%) | 2671 (57.4%) | 972 | 720 | 81 (3.0) | 1926 | 2313 |