Table 1. Characteristics of the Individuals in the Study According to SARS-CoV-2 Serology Test Results.
| Characteristica | Participants, No. (%) | P valueb | Standardized difference | ||
|---|---|---|---|---|---|
| Total (N = 18 148) | SARS-CoV-2 seropositive (n = 900) | SARS-CoV-2 seronegative (n = 17 248) | |||
| Age, y | |||||
| Median (IQR) | 47 (37-56) | 45 (36-54) | 48 (37-56) | <.001 | 0.18 |
| ≥60 | 2926 (16.1) | 112 (12.4) | 2814 (16.3) | .002 | 0.12 |
| <60 | 15 222 (83.9) | 788 (87.6) | 14 434 (83.7) | ||
| Sex | |||||
| Male | 5978 (32.9) | 252 (28.0) | 5726 (33.2) | .001 | 0.11 |
| Female | 12 170 (67.1) | 648 (72.0) | 11 522 (66.8) | ||
| Race/ethnicity | |||||
| Asian | 3026 (17.0) | 104 (11.7) | 2922 (17.3) | <.001 | 0.54 |
| Black | 3035 (17.1) | 284 (32.1) | 2751 (16.3) | ||
| Hispanic | 2439 (13.7) | 192 (21.7) | 2247 (13.3) | ||
| Otherc | 1482 (8.3) | 82 (9.3) | 1400 (8.3) | ||
| White | 7785 (43.8) | 224 (25.3) | 7561 (44.8) | ||
| Education | |||||
| No college degree | 8246 (46.6) | 513 (58.6) | 7733 (46.0) | <.001 | 0.25 |
| College degree | 9452 (53.4) | 363 (41.4) | 9089 (54.0) | ||
| Body mass index | |||||
| Median (IQR) | 28 (24-33) | 30 (26-35) | 28 (24-33) | <.001 | 0.24 |
| ≥30 | 6861 (37.9) | 426 (47.3) | 6435 (37.4) | <.001 | 0.20 |
| <30 | 11 265 (62.1) | 474 (52.7) | 10 791 (62.6) | ||
| Blood pressure | |||||
| High | 7886 (43.5) | 368 (40.9) | 7518 (43.6) | .17 | 0.06 |
| Elevated | 2818 (15.5) | 137 (15.2) | 2681 (15.6) | ||
| Normal | 7427 (41.0) | 395 (43.9) | 7032 (40.8) | ||
| Smoking | |||||
| Yes | 2238 (12.3) | 74 (8.2) | 2164 (12.6) | <.001 | 0.14 |
| No | 15 895 (87.7) | 826 (91.8) | 15 069 (87.4) | ||
| Geographical location | |||||
| Northeast | 3937 (21.8) | 155 (17.2) | 3782 (22.1) | <.001 | 0.32 |
| Midwest | 2835 (15.7) | 139 (15.5) | 2696 (15.7) | ||
| West | 4195 (23.3) | 132 (14.7) | 4063 (23.7) | ||
| South | 7057 (39.2) | 473 (52.6) | 6584 (38.4) | ||
| Vitamin D level in the prepandemic period, ng/mL | |||||
| Median (IQR) | 27 (20-35) | 24 (18-32) | 27 (20-35) | <.001 | 0.23 |
| <30 | 10 876 (59.9) | 611 (67.9) | 10 265 (59.5) | <.001 | 0.17 |
| ≥30 | 7272 (40.1) | 289 (32.1) | 6983 (40.5) | ||
| <20 | 4498 (24.8) | 290 (32.2) | 4208 (24.4) | <.001 | 0.17 |
| ≥20 | 13 650 (75.2) | 610 (67.8) | 13 040 (75.6) | ||
| Vitamin D level in the pandemic period, ng/mL | |||||
| Median (IQR) | 27 (20-36) | 25 (18-33) | 27 (20-36) | <.001 | 0.16 |
| <30 | 10 595 (58.4) | 586 (65.1) | 10 009 (58.0) | <.001 | 0.15 |
| ≥30 | 7553 (41.6) | 314 (34.9) | 7239 (42.0) | ||
| <20 | 4424 (24.4) | 260 (28.9) | 4164 (24.1) | .001 | 0.11 |
| ≥20 | 13 724 (75.6) | 640 (71.1) | 13 084 (75.9) | ||
Abbreviation: IQR, interquartile range.
SI conversion factor: To convert vitamin D level to nanomoles per liter, multiply by 2.496.
a
Body mass index (calculated as weight in kilograms divided by height in meters squared), blood pressure, and smoking status were determined during a biometric screening program that took place from September 2019 to January 2020.
b
Unadjusted results from the Wilcoxon rank-sum test for continuous variables and from the χ2 test for discrete variables.
c
Other includes American Indian or Alaska Native, Native Hawaiian or other Pacific Islander, or 2 or more races or ethnicities.