Figures
- FIGURE 1
Directed Acyclic Graph (DAG) identifying potential confounders for the relationship between asthma and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positive test. An arrow from a factor to another means possible association. Red circles indicate variables that require adjustment to assess the relationship between exposure (asthma, green) and the outcome (SARS-CoV-2 test, blue).
Tables
- TABLE 1
Demographic characteristics amongst all UK Biobank individuals who attended an assessment centre and amongst UK Biobank individuals with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) test data
All UK Biobank UK Biobank with SARS-CoV-2 test data Whole sample Whole sample# Positive Negative Subjects n 502 505 107 412 17 979 (17%) 89 433 (83%) Age at recruitment¶ (mean±sd) 56.53±8.10 56.70±8.25 53.52±8.58 57.33±8.03 Age at SARS-CoV-2 test¶ (mean±sd) 68.23±8.23 64.69±8.58 69.00±7.94 Sex¶ Female 54.0 54.0 52.9 54.3 Male 45.6 45.9 47.1 45.7 Ethnicity¶ White 94.1 93.6 89.5 94.5 Mixed 0.6 0.6 0.8 0.6 Asian 2.3 2.4 4.6 2.0 Black 1.6 1.8 2.9 1.5 Other ethnic background 1.3 1.3 1.9 1.2 Ever asthma Yes 12.6 13.9 14.1 13.9 No 87.0 85.6 85.4 85.7 Asthma age of onset (if asthma yes)¶ (mean±sd) 31.16±18.69 31.67±18.81 30.02±17.71 32.02±19.02 Asthma onset (if asthma yes) Early-onset (<13 years) 36.9 36.5 34.9 36.8 Late onset (≥13 years) 63.1 63.5 65.1 63.2 COPD diagnosis Yes 0.3 0.4 0.3 0.5 No 23.8 23.1 18.3 24.0 COPD age of onset 59.52±9.28 58.82±10.18 58.39±9.64 58.89±10.26 Hay fever or eczema diagnosis (mean±sd) Yes 23.6 24.0 23.6 24.1 No 75.9 75.6 75.9 75.5 Hay fever or eczema age of onset¶ 25.21±16.13 25.68±16.39 24.46±15.14 25.91±16.61 Asthma medication (if asthma yes) (mean±sd) No asthma/COPD medications 47.0 45.6 45.8 45.6 Only non-steroidal medications 15.4 14.8 14.7 14.8 Steroid medications 37.6 39.5 39.5 39.5 Hay fever medication (if hay fever yes) No hay fever medication 82.6 81.5 82.3 81.4 Medication; no antihistamines 7.2 7.5 7.3 7.6 Antihistamines 10.1 10.8 10.3 10.9 Lung function+ FEV1 at baseline, z-score¶ 0.37 (−0.32–1.08) 0.41−0.29–1.12) 0.44−0.27–1.16) 0.40−0.30–1.11) FVC at baseline, z-score¶ 0.18 (−0.48–0.84) 0.21 (−0.46–0.88) 0.24 (−0.44–0.92) 0.21 (−0.46–0.87) FEV1/FVC at baseline, z-score 0.34 (−0.16–0.90) 0.35 (−0.16–0.90) 0.34 (−0.16–0.92) 0.35 (−0.16–0.90) Household income GBP <18 000 18.9 19.7 20.1 19.6 18 000 to 30 999 21.5 21.2 20.2 21.4 31 000 to 51 999 22.3 22.1 23.6 21.8 52 000 to 100 000 17.8 17.2 17.3 17.2 >100 000 4.9 5.1 4.4 5.3 Education¶ None of the following 0.9 0.9 0.8 1.0 College or University degree 32.4 30.6 25.1 31.7 A levels/AS levels or equivalent 10.9 10.4 9.9 10.5 O levels/GCSEs or equivalent 20.8 21.0 22.4 20.7 CSEs or equivalent 5.3 5.5 8.8 4.8 NVQ or HND or HNC or equivalent 6.6 7.0 7.8 6.8 Other professional qualifications 5.2 5.3 4.8 5.5 Smoking history¶ Never 54.4 52.2 52.9 52.0 Past 34.4 36.3 35.0 36.6 Current 10.5 10.8 11.5 10.7 Smoking pack-years 19.00 (10.00–32.00) 19.88 (10.13–33.00) 20.00 (10.50–33.00) 19.88 (10.00–33.00) BMI¶ (mean±sd) 27.43±4.80 27.83±4.96 28.29±5.10 27.74±4.93 White blood cell count¶ 6.65 (5.63–7.86) 6.70 (5.69–7.90) 6.73 (5.70–7.99) 6.70 (5.69–7.90) Eosinophil count 0.14 (0.10–0.21) 0.14 (0.10–0.21) 0.14 (0.10–0.22) 0.14 (0.10–0.21) Close to major road Yes 7.0 7.2 7.4 7.1 No 91.5 91.5 91.4 91.5 Greenspace percentage, buffer 300 m¶ 29.53 (17.22–48.41) 29.53 (17.17–48.21) 27.44 (16.37–44.02) 29.97 (17.35–49.11) Values are % of participants, mean±sd or median (interquartile range) unless stated otherwise. FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; BMI: body mass index. #: sample of UK Biobank with SAR-CoV-2 test data differs from whole UK Biobank cohort (p<0.05) in all parameters except greenspace percentage, buffer 300 m. ¶: all p-values are <0.001, except for FVC at baseline, z-score (p=0.002) and white blood cell count (p=0.008). p-values are comparing positive and negative test result: chi-square for categorical exposures, ANOVA for parametric and Mann–Whitney U-test (Wilcoxon rank sum test) for non-parametric analysis of variance for continuous variables. +: z-score means represent the mean standard deviation of lung function parameters compared with values for age-, sex- and race-matched individuals.
- TABLE 2
Adjusted association between asthma and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positive test
Percentage of positive tests (n/N) OR (95% CI) for a positive test p-value Ever asthma No 16.6 (15 347/91 977) Ref Yes 16.9 (2539/14 988) 0.97 (0.92–1.02) 0.28 Asthma onset No asthma 16.6 (15 347/91 977) Ref Early-onset (<13 years) 16.2 (887/5469) 0.91 (0.84–0.99) 0.03 Late onset (≥13 years) 17.3 (1652/9519) 1.00 (0.94–1.07) 0.87 Adjusted for age at recruitment, sex and baseline measures of: education, average household income, smoking history, BMI, ethnicity, white blood cell count, eosinophil count, close to major road and greenspaces buffer. Bold values indicate p-value <0.05.
- TABLE 3
The associations between asthma age-of-onset phenotypes and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positive test by treatment and lung function
Early onset Late onset Percentage of positive tests (n/N) OR (95% CI) for a positive test Percentage of positive tests (n/N) OR (95% CI) for a positive test Asthma treatment No 15.8 (491/3114) Ref 18 (672/3727) Ref Treated with non-steroid 17.3 (112/645) 1.05 (0.81–1.36), p=0.67 16.5 (261/1576) 0.90 (0.75–1.08), p=0.26 Treated with steroids 16.6 (284/1710) 1.18 (0.98–1.42), p=0.07 17.1 (719/4216) 1.04 (0.91–1.19), p=0.55 Quartiles of baseline FEV1 Q1 of FEV1 (lowest quartile) 12.4 (70/562) Ref 18.3 (190/1035) Ref Q2 of FEV1 16.7 (120/715) 1.25 (0.88–1.79), p=0.20 15.2 (203/1332) 0.81 (0.64–1.03), p=0.09 Q3 of FEV1 14.8 (145/976) 1.22 (0.87–1.72), p=0.23 16.9 (280/1653) 0.92 (0.73–1.15), p=0.48 Q4 of FEV1 16.7 (310/1851) 1.44 (1.05–1.72), p=0.02 17.4 (516/2962) 0.90 (0.73–1.15), p=0.36 FEV1: forced expiratory volume in 1 s.
- TABLE 4
The associations between asthma onset phenotypes and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positive test stratified by sex, baseline smoking, obesity and ethnicity (NEW)
Percentage of positive tests (n/N) OR (95% CI) for a positive test Percentage of positive tests (n/N) OR (95% CI) for a positive test p-value for interaction Male Female Sex Asthma onset 0.53 No asthma 17.2 (7374/42 981) Ref 16.3 (7973/48 996) Ref Early-onset (<13 years) 15.5 (417/2684) 0.86 (0.76–0.97), p=0.01 16.8 (470/2785) 0.94 (0.83–1.06), p=0.33 0.29 Late onset (≥13 years) 18.1 (626/3464) 1.00 (0.91–1.11), p=0.88 16.9 (1023/6055) 0.99 (0.92–1.08), p=0.95 0.75 Never smoked Ever smoked Smoking Asthma onset 0.71 No asthma 16.9 (8156/48 191) Ref 16.4 (7152/43 479) Ref Early-onset (<13 years) 16.5 (495/3003) 0.87 (0.78–0.98), p=0.02 16.0 (399/2497) 0.94 (0.84–1.07), p=0.40 0.45 Late onset (≥13 years) 17.4 (819/4711) 1.00 (0.91–1.09), p=0.86 17.2 (793/4589) 1.00 (0.91–1.09), p=0.97 0.79 Normal weight Overweight/Obese BMI Asthma onset 0.03 No asthma 14.8 (4202/28 226) Ref 17.4 (11 036/63 271) Ref Early-onset (<13 years) 16.1 (264/1634) 1.09 (0.94–1.27), p=0.22 16.2 (625/3854) 0.85 (0.77–0.93), p=0.001 0.01 Late onset (≥13 years) 14.4 (330/2280) 0.94 (0.82–1.08), p=0.43 18.2 (1293/7070) 1.02 (0.94–1.09), p=0.59 0.41 Non-black Black Ethnicity Asthma onset 0.32 No asthma 16.5 (14 900/90 327) Ref 27.1 (444/1637) Ref Early-onset (<13 years) 15.9 (859/5389) 0.90 (0.82–0.98), p=0.01 34.6 (27/78) 1.54 (0.90–2.6), p=0.11 0.14 Late onset (≥13 years) 17.1 (1601/9355) 0.99 (0.93–1.06), p=0.89 31.1 (51/164) 1.18 (0.79–1.7), p=0.40 0.67 Adjusted for age at recruitment, sex, and baseline measures of: education, average household income, smoking history, BMI, ethnicity, white blood cell count, eosinophil count, close to major road and greenspaces buffer. Bold values indicate p-value <0.05.
