ObjectiveThe current study estimates trends in the number of cigarettes smoked per day (CPD) and percentage of smokers having their first CPD within 30 min of waking (time to first cigarette (TTFC)<30 min) among smokers from 2002 to 2015 in the USA overall, and adjusting for demographics. Trends in TTFC<30 min were also estimated by varying levels of cigarette consumption.MethodsData were drawn from the National Household Survey on Drug Use, an annual nationally representative cross-sectional study of the US population aged 12 and older (n=54 079–58 397 per year). Linear time trend analyses of CPD and TTFC<30 min were conducted adjusting for age, gender and income; linear time trend analyses of TTFC among those at varying levels of CPD were then performed.ResultsEstimates suggest that CPD declined overall from 2002 to 2015, and that the prevalence of TTFC<30 min declined overall among smokers (p<0.0001). The proportion of smokers consuming fewer (ie, 1–5, 6–15) CPD has increased while the number consuming 16+ CPD has decreased overall. Among those smoking 1–5 (p=0.0006) and 6–15 (p<0.0001) CPD, TTFC<30 min has increased significantly, but TTFC<30 min has remained unchanged among those smoking 16 or more CPD (p=0.5838).ConclusionsFindings suggest that smokers today are consuming fewer CPD, yet are increasingly likely to have their first cigarette earlier on awakening than they were a decade ago. Intervention and outreach efforts aimed at moving the prevalence lower may benefit from evaluating and addressing nicotine dependence even among lighter smokers.
On the Estimation of a Linear Time Trend Regression with a One-Way Error Component Model in the Presence of Serially Correlated Errors
