Skip to main content
. 2021 Aug 30;10(8):e28169. doi: 10.2196/28169

Table 2.

Baseline characteristics of participants in the COVID-19 Citizen Science study as of January 14, 2021 (N=46,106).

Characteristica Value
Age at consent (years), n (%) (n=46,106)

18-39 20,897 (45.3)

40-64 21,475 (46.6)

≥65 3734 (8.1)
Sex at birth, n (%) (n=42,902)

Male 13,437 (31.3)

Female 29,391 (68.5)

Decline 74 (0.2)
Gender identity, n (%) (n=42,890)

Male 13,289 (31)

Female 28,904 (67.4)

Transgender woman 53 (0.1)

Transgender man 92 (0.2)

Genderqueer 327 (0.8)

Other 137 (0.3)

Decline 98 (0.2)
Race, n (%) (n=42,418)

Black or African American 875 (2.1)

White 38,086 (89.8)

Asian 3150 (7.4)

Native Hawaiian or Pacific Islander 131 (0.3)


American Indian or Alaska Native 569 (1.3)


Other or don’t know 1516 (3.6)
Hispanic ethnicity, n (%) (n=42,902) 3305 (7.7)
Subjective social status, median (IQR) (n=42,898) 7 (6-8)

Educational attainment, n (%) (n=42,885)

High school or less 1951 (4.5)

Some college 6864 (16)

Bachelor’s 15,394 (35.9)

Postgraduate 18,140 (42.3)

Other, don’t know, or prefer not to state 536 (1.2)
Residence in USA, n (%) (n=43,905) 41,058 (93.5)
Residence: USA region, n (%) (n=40,943)

West 20,146 (49.2)

Midwest 6662 (16.3)

Northeast 5723 (14)

South 8412 (20.5)
Exercise, n (%) (n=43,819)

Never 2775 (6.3)

Less than once per month 4146 (9.4)

Once per month to once per week 5857 (13.3)

Once per week 5792 (13.2)

1 to 4 times per week 13,275 (30.2)

4 or more times per week 11,900 (27.1)

Other 146 (0.3)
Alcohol consumption (drinks/week), median (IQR) (n=27,649) 2 (0-5)
Current smoking, n (%) (n=41,604) 2385 (5.7)
Current e-cigarette use, n (%) (n=41,682) 1408 (3.4)
Medical condition, n (%)

Hypertension (n=42,783) 7969 (18.6)


Diabetes (n=42,780) 1676 (3.9)

Coronary artery disease (n=42,781) 979 (2.3)

Myocardial infarction (n=42,781) 402 (0.9)

Congestive heart failure (n=42,781) 266 (0.6)

Stroke or transient ischemic attack (n=42,783) 520 (1.2)

Atrial fibrillation (n=42,780) 1128 (2.6)

Sleep apnea (n=42,781) 4226 (9.8)

Chronic obstructive pulmonary disease (n=42,782) 682 (1.6)

Asthma (n=42,780) 4414 (10.3)

Cancer (active) (n=42,779) 1272 (2.9)

Immunodeficiency (n=42,783) 867 (2)

HIV (n=42,783) 179 (0.4)

Anemia (n=42,780) 4530 (10.6)

Pregnant (n=42,781) 515 (1.2)
Tested positive for COVID-19 before baseline, n (%) (n=43,905) 1214 (2.8)

aNot all participants provided responses to all survey questions, so the denominator for each characteristic differs.