Table 5. Antibody test result according to key variables, stratified by cohort.

Differences assessed using chi-squared test for categorical variables and t-test for continuous variables; n (%) for categorical variables or mean (standard deviation; SD) for continuous variables. A positive result is defined as either an ‘IgG positive’ or ‘IgG and IgM positive’ result, while a negative result is defined as either a ‘negative’ or ‘IgM positive’ result.

	Positive result	Negative result	p-value
Age (years) G0 G1	58.2 (4.6) 28.2 (0.6)	59.2 (4.7) 28.3 (1.1)	0.077 0.763
Gender G0 – Male          Female G1 – Male          Female	18 (2.6%) 63 (3.3%) 29 (5.0%) 91 (5.9%)	681 (97.4%) 1856 (96.7%) 552 (95.0%) 1464 (91.2%)	0.355 0.442
Education G0 – O levels or lower          A levels or higher G1 – O levels or lower          A levels or higher	36 (3.6%) 44 (2.9%) 17 (5.0%) 81 (6.1%)	961 (96.4%) 1454 (97.1%) 323 (95.0%) 1252 (93.9%)	0.35 0.451
BMI G0 G1	27.1 (6.1) 24.6 (5)	26.5 (4.7) 24.9 (5.3)	0.372 0.491
Systolic BP G0 G1	121.9 (15.5) 116.5 (12.6)	123.1 (15.1) 115.2 (10.8)	0.528 0.216
Diastolic BP G0 G1	70.9 (9.1) 67.3 (8.3)	72.4 (9.8) 67 (8)	0.197 0.668

BMI=body mass index; BP=blood pressure