Table 1

Characteristics of study subjects by category

All usersSelf-reported COVID-19SARS-CoV-2 testedP valueStandard users
AllNegativePositive
Demographics
N (%)2 401 982157 406 (6.5)26 918 (1.1)16 759 (0.7)7123 (0.3)2 221 088 (92.4)
Sex (% F)63.364.3968.8168.4167.820.40163.16
Age43.63±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)
<2.2×10−1643.73±15.14
(32–55)
BMI26.47±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)
9.04×10–726.44±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)<2.2×10−1668 188 (3.07)
Ethnicity (%)
 Asian6014 (2.1)395 (3.02)120 (4.72)51 (3.63)50 (6.39)5525 (2.03)
 Black1700 (0.59)123 (0.94)27 (1.06)15 (1.07)10 (1.28)1555 (0.57)
 Chinese1040 (0.36)52 (0.4)16 (0.63)11 (0.78)4 (0.51)975 (0.36)
 Middle East1219 (0.43)81 (0.62)16 (0.63)6 (0.43)7 (0.89)1128 (0.42)
 Mixed4260 (1.49)272 (2.08)28 (1.10)14 (1.00)5 (0.64)3969 (1.46)
 White272 537 (95.04)12 142 (92.94)2335 (91.86)1309 (93.10)707 (90.29)258 508 (95.16)
 N/A2 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)*
Overall240 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)
1.10×10–5220 135; 132 927; 87 064
(10.79; 10.17; 11.90)
Age (years)
 16–2430 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)
 25–44135 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)
 45–6466 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)
 >658423; 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 (%)
 Diabetes2.842.52.952.763.262.86
 Heart disease2.031.682.112.331.692.06
 Lung disease12.213.3814.6915.0113.3812.09
 Kidney disease0.590.570.90.950.830.59
 Cancer1.210.671.752.290.941.26
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.