Sample Characteristics

Original Sample, n = 191 660MI Sample, m = 10, n = 191 660
Dependent Variables%% Missing%
Lifetime NPOU7.62.97.6
Lifetime heroin use1.52.51.6
History of initiating NPOU in relation to initiating heroin
 No lifetime NPOU or heroin use95.611.095.3
 Lifetime NPOU only3.53.7
 Lifetime heroin use only0.250.27
 Initiated NPOU and heroin use in the same grade0.380.42
 Initiated NPOU in ≥1 grade before heroin use0.170.19
 Initiated heroin use in ≥1 grade before initiating NPOU0.100.11
Participation in sports and exercise (independent variables)
 No past-year participation in sports and exercise (reference)7.890.707.9
 Participates in sports and exercise once a week at most38.838.8
 Participates in sports and exercise almost every day53.353.3
Control variables
 Male (reference)48.83.548.9
 White (reference)57.40.0057.4
 Respondent is in 8th grade (reference)52.00.5252.1
 Respondent is in 10th grade48.047.9
 Never has been suspended from school (reference)75.43.575.1
 Has been suspended ≥1 time from school24.624.9
 Both parents have less than a college degree (reference)
 ≥1 Parent has a college degree or higher51.050.9
 Respondent lives in a non-MSA (reference)
 Respondent lives in an MSA47.047.0
 Respondent lives in a large MSA30.830.8
 Respondent lives in the Northeast (reference)
 Respondent lives in the Midwest24.124.1
 Respondent lives in the South35.635.6
 Respondent lives in the West21.621.6
 Cohort years (1997–1999) (reference)
 Cohort years (2000–2002)16.216.2
 Cohort years (2003–2005)17.617.6
 Cohort years (2006–2008)17.117.1
 Cohort years (2009–2011)16.516.5
 Cohort years (2012–2014)15.315.3
 No lifetime cigarette use (reference)65.32.665.5
 Lifetime cigarette use34.734.5
 No lifetime alcohol use (reference)
 Lifetime alcohol use52.352.6
 No lifetime illicit drug use (excluding opioids) (reference)
 Lifetime illicit drug use (excluding opioids)38.738.7
 No lifetime heroin use (reference)98.97.698.9
 Initiated heroin use in 4th grade or 7th grade0.490.53
 Initiated heroin use in 8th, 9th, or 10th grade0.590.61
 No lifetime NPOU (reference)95.610.195.3
 Initiated NPOU in 4th through 7th grade1.11.3
 Initiated NPOU in 8th, 9th, or 10th grade3.23.4
  • MI, multiple imputation; MSA, Metropolitan Statistical Area. Weighted sample is provided; n = 191 660.