Assessing 30-day quantity-frequency of U.S. adolescent cigarette smoking as a predictor of adult smoking 14 years later

Abstract

BackgroundTo improve measures of monthly tobacco cigarette smoking among non-daily smokers, predictive of future non-daily monthly and daily smoking. MethodsData from United States National Longitudinal Study of Adolescent to Adult Health, tracking adolescents, ages 12–21, over 14 years were analyzed. At baseline, 6501 adolescents were assessed; 5114 individuals provided data at waves 1 and 4. Baseline past 30-day non-daily smokers were classified using quantity-frequency measures: cigarettes smoked/day by number of days smoked in the past 30days. ResultsThree categories of past 30-day non-daily smokers emerged using cigarettes/month (low:1–5, moderate: 6–60, high: 61+) and predicted past 30-day smoking at follow-up (low: 44.5%, moderate: 60.0%, high: 77.0%, versus 74.2% daily smokers; rτ=−0.2319, p<0.001). Two categories of non-smokers plus low, moderate and high categories of non-daily smokers made up a five-category non-daily smoking index (NDSI). High NDSI (61+ cigs/mo.) and daily smokers were equally likely to be smoking 14 years later (High NDSI OR=0.97, 95% CI=0.53–1.80 [daily as reference]). Low (1–5 cigs/mo.) and moderate (6–60 cigs/mo.) NDSI were distinctly different from high NDSI, but similar to one another (OR=0.21, 95% CI=0.15–0.29 and OR=0.22, 95% CI=0.14–0.34, respectively) when estimating future monthly smoking. Among those smoking at both waves, wave 1 non-daily smokers, overall, were less likely than wave 1 daily smokers to be smoking daily 14 years later. ConclusionsNon-daily smokers smoking over three packs/month were as likely as daily smokers to be smoking 14-years later. Lower levels of non-daily smoking (at ages 12–21) predicted lower likelihood of future monthly smoking. In terms of surveillance and cessation interventions, high NDSI smokers might be treated similar to daily smokers.