Table 1. Participant Characteristics by Enrollment Cohort: Adolescents in Northern California, US (2019-2020).
| Baseline characteristic | No. (%) | P valued | |
|---|---|---|---|
| Spring 2019 cohort (n = 521)a,b | Fall 2019 cohort (n = 485)b,c | ||
| Grade in school | |||
| Ninth | 247 (48.4) | 328 (68.6) | <.001 |
| Tenth | 263 (51.6) | 150 (31.4) | |
| Sex | |||
| Female | 311 (59.7) | 312 (64.3) | .10 |
| Male | 206 (39.5) | 165 (34.0) | |
| Other | 4 (0.8) | 8 (1.6) | |
| Race/ethnicity | |||
| Hispanic/Latinx | 185 (34.6) | 173 (35.7) | .98 |
| Non-Hispanic White | 256 (49.9) | 236 (48.7) | |
| Othere | 80 (15.5) | 76 (15.7) | |
| Computers at home, No. | |||
| 0 | 46 (9.0) | 58 (12.1) | .04 |
| 1 | 136 (26.7) | 113 (23.6) | |
| 2 | 112 (22.0) | 133 (27.8) | |
| >2 | 215 (42.24) | 175 (36.5) | |
| Family vacations in past year, No. | |||
| 0 | 107 (21.1) | 92 (19.1) | .09 |
| 1 | 115 (22.7) | 142 (29.5) | |
| 2 | 111 (21.9) | 105 (21.8) | |
| >2 | 174 (34.3) | 143 (29.7) | |
| School lunch program | |||
| Free or reduced | 253 (51.7) | 312 (64.3) | <.001 |
| Full price | 183 (37.4) | 86 (17.7) | |
| Do not know | 53 (10.8) | 87 (17.9) | |
| Scholastic performance | |||
| Mostly A’s | 210 (40.4) | 227 (46.9) | .21 |
| Mostly B’s | 202 (38.8) | 166 (34.3) | |
| Mostly C’s or below | 83 (16.0) | 72 (14.9) | |
| Do not know | 25 (4.8) | 19 (3.9) | |
| Depression symptoms | |||
| Positive screen | 167 (32.2) | 153 (31.8) | .90 |
| Negative screen | 352 (67.8) | 328 (68.2) | |
| e-Cigarette use in past 30 d | |||
| Never | 327 (62.8) | 301 (62.1) | .79 |
| Ever (0 d) | 101 (19.4) | 87 (17.9) | |
| 1-5 d | 55 (10.6) | 55 (11.3) | |
| 6-30 d | 38 (7.3) | 42 (8.7) | |
| Other tobacco use in past 30 dd | |||
| 0 d | 487 (93.5) | 467 (96.3) | .04 |
| 1-30 d | 34 (6.5) | 18 (3.7) | |
| Cannabis use in past 30 d | |||
| Never | 351 (67.4) | 303 (62.5) | .20 |
| Ever (0 d) | 77 (14.8) | 87 (17.9) | |
| 1-5 d | 53 (10.2) | 63 (13.0) | |
| 6-30 d | 40 (7.7) | 32 (6.6) | |
| Alcohol use in past 30 d | |||
| 0 d | 428 (82.1) | 386 (79.8) | .33 |
| 1-30 d | 93 (17.9) | 98 (20.2) | |
| Physically active in past week | |||
| 0-1 d | 51 (9.8) | 42 (8.7) | .83 |
| 2-4 d | 190 (36.5) | 180 (37.3) | |
| 5-7 d | 279 (53.7) | 261 (54.0) | |
| Sensation-seeking score, standardized mean (SD) | −0.05 (0.98) | −0.07 (1.01) | .75 |
| Has a follow-up responsef | |||
| Before March 20, 2020 | 521 (100) | 0 (0) | NA |
| After March 19, 2020 | 387 (74.3) | 485 (100) | NA |
Abbreviation: NA, not applicable.
Includes participants from schools recruited March 2019 to May 2019 and whose 6-month follow-up was completed before the March 19, 2020, California stay-at-home order. This also includes 51 participants recruited in August 2019 and whose 6-month follow-up responses were collected from February 27, 2020, to March 7, 2020.
This Table includes only individuals with a 6-month follow-up observation. For a comparison of the full baseline sample to the follow-up analytic sample, including 12-month follow-up, see eTable 1 in the Supplement. Number of participants may be smaller for some variables owing to missing data.
Includes participants from schools recruited August 2019 to February 2020 and whose 6-month follow-up was completed after the March 19, 2020, California stay-at-home order.
χ2 Test to compare the spring and fall cohorts; exception: sensation-seeking score tested with t test.
Other race/ethnicity included American Indian or Alaska Native, Asian, Black, Native Hawaiian or Pacific Islander, more than 1 race, prefer not to respond, and missing data.
Follow-up completed after March 19, 2020, in the spring 2019 cohort refers to 12-month follow-up.