Table 1 Descriptive statistics of the independent, dependent, mediating and controlling variables (n = 3,975)

Dependent variable

E-cigarette use in past 30 days in Wave 5 (0 ~ 30, Mean ± SD)

1.75 ± 5.97

Independent variable

Social Media Usage Wave 3 (1 ~ 7, Mean ± SD)

5.91 ± 1.62

Mediating variable

Internalizing Problems in Wave 4 (0 ~ 4, Mean ± SD)

1.91 ± 1.62

Moderating variable

Academic Performance in Wave 4 (1 ~ 9, Mean ± SD)

7.36 ± 1.67

Covariates

Age in Wave 3 (n. %)

12–14

3,882 (97.7)

15–17

93 (2.3)

Gender in Wave 3 (n. %)

Female

2.048 (51.5)

Male

1,914 (48.2)

Race in Wave 3 ((n. %)

White alone

2,470 (62.1)

African American alone

644 (16.2)

Other

625 (15.7)

Household income in Wave 3 (n. %)

Less than $10,000

312 (7.8)

$10,000 to $24,999

670 (16.9)

$25,000 to $49,999

913 (23.0)

$50,000 to $99,999

907 (22.8)

$100,000 or more

933 (23.5)

Self-perceived physical health in Wave 3 (1 ~ 5, Mean ± SD)

4.14 ± 0.93

Self-perceived mental health in Wave 3 (1 ~ 5, Mean ± SD)

3.72 ± 1.18

Exposed to Family secondhand smoke in Wave 3 (n. %)

Yes

1,307 (32.9)

No

2,593 (65.2)

Internalizing Problems in Wave 3 (0 ~ 4, Mean ± SD)

1.76 ± 1.56

E-cigarette use in past 30 days in Wave 3 (0 ~ 30, Mean ± SD)

0.09 ± 1.11

E-cigarette use in past 30 days in Wave 4 (0 ~ 30, Mean ± SD)

0.15 ± 1.48