Volume 30, Number 7—July 2024
Research
Prevalence of and Risk Factors for Post–COVID-19 Condition during Omicron BA.5–Dominant Wave, Japan
, Mariko Hosozawa, Miyuki Hori, Yoko Muto, Isao Muraki, Rie Masuda, Nanako Tamiya, and Hiroyasu Iso
Table 2
Characteristics of participants in study of prevalence and risk factors for post–COVID-19 condition during BA.5 Omicron-dominant wave, Japan*
| Characteristic | Cases, n = 8,392 | Controls, n = 6,318 | p value | ||
|---|---|---|---|---|---|
| Mean age, y (+SD) |
42.3 (+11.6) |
42.4 (+11.8) |
0.63 |
||
| Age group, y | 0.29 | ||||
| 20–29 | 1,316 (15.7) | 1,036 (16.4) | |||
| 30–39 | 2,340 (27.9) | 1,674 (26.5) | |||
| 40–49 | 2,326 (27.7) | 1,766 (28.0) | |||
| 50–59 | 1,695 (20.2) | 1,270 (20.1) | |||
| 60–70† |
715 (8.5) |
572 (9.1) |
|||
| Patient sex | 0.01 | ||||
| M | 3,535 (42.1) | 2,552 (40.4) | |||
| F | 4,802 (57.2) | 3,700 (58.6) | |||
| Prefer not to answer |
55 (0.7) |
66 (1.0) |
|||
| Mean BMI, kg/m2 (+SD) |
22.1 (+3.5) |
22.3 (+3.8) |
0.08 |
||
| BMI, kg/m2 | 0.001 | ||||
| <18.5 | 932 (11.1) | 757 (12.0) | |||
| 18.5–25.0 | 5,902 (70.3) | 4,271 (67.6) | |||
| >25.0 |
1,406 (16.8) |
1,174 (18.6) |
|||
| Underlying medical conditions‡ | 0.01 | ||||
| 0 | 6,445 (76.8) | 4,752 (75.2) | |||
| 1 | 1,382 (16.5) | 1,057 (16.7) | |||
| >2 | 565 (6.7) | 509 (8.1) | |||
| Hypertension | 557 (6.6) | 441 (7.0) | 0.41 | ||
| Dyslipidemia | 396 (4.7) | 362 (5.7) | 0.01 | ||
| Respiratory diseases | 394 (4.7) | 317 (5.0) | 0.37 | ||
| Depression/anxiety | 272 (3.2) | 243 (3.8) | 0.05 | ||
| Heart diseases | 197 (2.3) | 180 (2.8) | 0.06 | ||
| Malignancy | 169 (2.0) | 131 (2.1) | 0.80 | ||
| Diabetes |
152 (1.8) |
167 (2.6) |
0.001 |
||
| No. COVID-19 vaccinations§ | <0.001 | ||||
| 0 | 685 (8.2) | 412 (6.5) | |||
| 1 | 49 (0.6) | 28 (0.4) | |||
| 2 | 1,675 (20.0) | 1,145 (18.1) | |||
| >3 |
5,983 (71.3) |
4,733 (74.9) |
|||
| Household income, ¥ | 0.002 | ||||
| <4 million | 2,520 (34.5) | 2,022 (32.0) | |||
| 4–8 million | 3,699 (50.7) | 2,614 (41.4) | |||
| >8 million |
1,077 (14.8) |
858 (13.6) |
|||
| Education level | 0.68 | ||||
| High school or lower | 1,242 (14.8) | 961 (15.2) | |||
| Some college | 1,710 (20.4) | 1,259 (19.9) | |||
| College or higher |
5,299 (63.1) |
4,004 (63.4) |
|||
| Mean follow-up, d (+SD) |
167.9 (+14.5) |
NA |
|||
| No. SARS-CoV-2 infections | |||||
| 1 | 8,284 (98.7) | NA | |||
| 2 |
108 (1.3) |
NA |
|||
| Severity of infection | |||||
| Asymptomatic | 228 (2.7) | NA | |||
| Mild | 8,098 (96.5) | NA | |||
| Moderate/severe | 66 (0.8) | NA | |||
*Values are no. (%) except as indicated. Continuous variables were compared by using t-tests; categorical variables were compared by using χ2 tests. BMI, body mass index; NA, not applicable. †Includes patients who turned 70 years of age between the participant selection and survey periods. ‡Respiratory diseases included interstitial lung diseases, asthma, and chronic obstructive pulmonary diseases. Heart diseases included myocardial infarction, angina, heart failure, arrhythmia, myocarditis, and cardiomyopathy. Mental disorder included anxiety and depression. §Number of vaccinations administered until 14 d before infection (cases) or before June 2022 (controls).