Characteristics of study subjects by category
| All users | Self-reported COVID-19 | SARS-CoV-2 tested | P value | Standard users | |||
| All | Negative | Positive | |||||
| Demographics | |||||||
| N (%) | 2 401 982 | 157 406 (6.5) | 26 918 (1.1) | 16 759 (0.7) | 7123 (0.3) | 2 221 088 (92.4) | |
| Sex (% F) | 63.3 | 64.39 | 68.81 | 68.41 | 67.82 | 0.401 | 63.16 |
| Age | 43.63±15.01 (32–55) | 42.5±13.26 (32–52) | 42.35±13.23 (32–52) | 43.2±13.51 (33–53) | 41.16±12.69 (31–50) | <2.2×10−16 | 43.73±15.14 (32–55) |
| BMI | 26.47±5.48 (22.67–29.1) | 26.85±5.71 (22.83–29.65) | 26.91±5.78 (22.78–29.8) | 26.71±5.65 (22.71–29.53) | 27.26±5.94 (23.05–30.13) | 9.04×10–7 | 26.44±5.46 (22.67–29.05) |
| Healthcare worker (%) | 83 120 (3.46) | 10 533 (6.69) | 5385 (20.01) | 2391 (14.27) | 2218 (31.14) | <2.2×10−16 | 68 188 (3.07) |
| Ethnicity (%) | |||||||
| Asian | 6014 (2.1) | 395 (3.02) | 120 (4.72) | 51 (3.63) | 50 (6.39) | 5525 (2.03) | |
| Black | 1700 (0.59) | 123 (0.94) | 27 (1.06) | 15 (1.07) | 10 (1.28) | 1555 (0.57) | |
| Chinese | 1040 (0.36) | 52 (0.4) | 16 (0.63) | 11 (0.78) | 4 (0.51) | 975 (0.36) | |
| Middle East | 1219 (0.43) | 81 (0.62) | 16 (0.63) | 6 (0.43) | 7 (0.89) | 1128 (0.42) | |
| Mixed | 4260 (1.49) | 272 (2.08) | 28 (1.10) | 14 (1.00) | 5 (0.64) | 3969 (1.46) | |
| White | 272 537 (95.04) | 12 142 (92.94) | 2335 (91.86) | 1309 (93.10) | 707 (90.29) | 258 508 (95.16) | |
| N/A | 2 115 212 (88.06) | 144 341 (91.70) | 24 376 (90.56) | 15 353 (91.61) | 6 340 (89.01) | 1 949 428 (87.77) | |
| Smoking prevalence (% all; % F; % M)* | |||||||
| Overall | 240 873; 146 010; 94 697 (10.96; 10.35; 12.05) | 18 845; 11 776; 7048 (13.79; 13.26; 14.76) | 2182; 1502; 678 (8.93; 8.87; 9.08) | 1418; 944; 473 (9.26; 8.92; 10.01) | 472; 333; 138 (7.40; 7.67; 6.79) | 1.10×10–5 | 220 135; 132 927; 87 064 (10.79; 10.17; 11.90) |
| Age (years) | |||||||
| 16–24 | 30 510; 20 167; 10 313 (13.79; 13.02; 15.55) | 2334; 1523; 805 (19.00; 17.86; 21.5) | 253; 177; 75 (14.93; 14.38; 16.27) | 153; 101; 52 (15.07; 14.13; 17.39) | 61; 46; 14 (13.26; 13.77; 11.29) | 27 952; 18 485; 9443 (13.47; 12.73; 15.20) | |
| 25–44 | 135 199; 82 509; 52 594 (13.11; 12.07; 15.14) | 11 093; 6 848; 4233 (16.13; 15.21; 17.85) | 1288; 906; 381 (9.95; 9.78; 10.38) | 811; 548; 262 (10.38; 9.82; 11.76) | 302; 222; 80 (8.54; 8.92; 7.68) | 122 980; 74,865; 48 032 (12.93; 11.88; 14.99) | |
| 45–64 | 66 741; 39,238; 27 468 (8.96; 8.46; 9.79) | 5135; 3,253; 1879 (10.48; 10.32; 10.76) | 591; 396; 195 (6.88; 6.85; 6.95) | 413; 274; 139 (7.40; 7.29; 7.66) | 104; 64; 40 (4.73; 4.47; 5.21) | 61 110; 35 654; 25 424 (8.87; 8.34; 9.75) | |
| >65 | 8423; 4096; 4322 (4.21; 3.78; 4.71) | 283; 152; 131 (4.27; 4.02; 4.60) | 50; 23; 27 (4.16; 3.44; 5.07) | 41; 21; 20 (4.48; 3.97; 5.18) | 5; 1; 4 (2.72; 1.18; 4.04) | 8093; 3923; 4165 (4.21; 3.78; 4.71) | |
| Comorbidities (%) | |||||||
| Diabetes | 2.84 | 2.5 | 2.95 | 2.76 | 3.26 | 2.86 | |
| Heart disease | 2.03 | 1.68 | 2.11 | 2.33 | 1.69 | 2.06 | |
| Lung disease | 12.2 | 13.38 | 14.69 | 15.01 | 13.38 | 12.09 | |
| Kidney disease | 0.59 | 0.57 | 0.9 | 0.95 | 0.83 | 0.59 | |
| Cancer | 1.21 | 0.67 | 1.75 | 2.29 | 0.94 | 1.26 | |
| Hospital attendance | <2.2×10−16 | ||||||
| N (%) | 12 093 (1.45) | 2746 (2.84) | 2753 (14.39) | 1250 (12.16) | 1148 (18,35) | 7208 (1.00) | |
*Smoking prevalence in the UK (adult smoking habits in the UK: 2018, Office for National Statistics). Overall: 14.7% (16.5% of men; 13% of women). By age group: 18–24: 16.8%; 25–34: 19.2%; 35:44: 16.4%; 45:54: 16.8%; 55:64: 14.5%; ≥65: 7.9. Age and BMI are given as mean±SD and first, third IQR (in brackets). Standard users refers to individuals who did not believe that they already had COVID-19 when registering with the app and had not been tested for SARS-CoV-2. Significant differences in study variables between tested positive and tested negative subjects are shown (P). Categorical variables (ie, gender, healthcare worker and smoking) were compared using Pearson’s χ2 test, while age was compared using Wilcoxon’s test. Association of p values with BMI is from linear regression adjusting for age and sex. The ‘self-reported COVID-19’ group includes 1295 and 1767 individuals who reported having tested positive and negative for SARS-CoV-2, respectively.
BMI, body mass index.