Demographic characteristics of participants and those who reported wheeze, bronchitic symptoms, shortness of breath or secondhand nicotine vape exposure during the study period*
| Total | Wheeze† | Bronchitic symptoms† | Shortness of breath† | Secondhand nicotine vape exposure† | |
| N=2090 | N=510 | N=811 | N=480 | N=542 | |
| Race | |||||
| Asian | 72 (3.4) | 16 (3.1) | 27 (3.3) | 19 (4.0) | 17 (3.1) |
| Black | 31 (1.5) | 9 (1.8) | 12 (1.5) | 2 (0.4) | 6 (1.1) |
| Hispanic white | 1081 (51.8) | 214 (42.0) | 378 (46.7) | 254 (53.0) | 241 (44.5) |
| Non-hispanic white | 732 (35.1) | 222 (43.5) | 320 (39.5) | 168 (35.1) | 237 (43.7) |
| Others | 172 (8.2) | 49 (9.6) | 73 (9.0) | 36 (7.5) | 41 (7.6) |
| Parental education at baseline | |||||
| Completed grade 12 or less | 574 (27.5) | 113 (22.2) | 185 (22.8) | 142 (29.6) | 128 (23.6) |
| Some college | 648 (31.0) | 164 (32.2) | 268 (33.0) | 154 (32.1) | 208 (38.4) |
| Completed college or more | 622 (29.8) | 183 (35.9) | 279 (34.4) | 136 (28.3) | 153 (28.2) |
| Missing | 246 (11.8) | 50 (9.8) | 79 (9.7) | 48 (10.0) | 53 (9.8) |
| Sex | |||||
| Female | 1036 (49.6) | 258 (50.6) | 419 (51.7) | 337 (70.2) | 264 (48.7) |
| Male | 1054 (50.4) | 252 (49.4) | 392 (48.3) | 143 (29.8) | 278 (51.3) |
*χ2 tests were performed comparing the demographic characteristics of participants with wheeze, bronchitic symptoms, shortness of breath, secondhand nicotine vape exposure to participants without the specific respiratory outcome or secondhand nicotine vape. N (%) is shown in the table. Significant differences (p<0.05) are shown in bold.
†Total number of participants reporting wheeze, bronchitic symptoms, shortness of breath or secondhand nicotine vape exposure, at least once, over the study period (waves 1–4).