We investigated contexts of simultaneous use of alcohol and marijuana and the impact of simultaneous use on problems among adolescents. Ecological momentary assessment data were obtained over two weekends from 150 adolescents in California (47% female, M age = 16.36 years), using smartphone surveys administered early and late in the evening and again the following morning. We assessed whether, in what context, and with whom adolescents drank alcohol and used other substances over 3 evening hours. We assessed problems they experienced each evening on the following morning. Results showed that greater adult supervision in every context was associated with a 55% lower risk of simultaneous use (RRR=0.45, p≤ .05). Contexts with no other underage drinkers were associated with 99% lower risk of simultaneous use (RRR=0.01, p≤ .005). Each occasion of simultaneous use was related to 110% increase in the number of problems (IRR=2.10, p≤ .005), with 83%, 221% and 311% greater odds of violence (OR=1.83, p≤ .05), driving under the influence or riding with a drunk driver (OR=3.21, p≤ .05), or being drunk (OR=4.11, p≤ .005). Additional analyses showed that these problems may be attributed largely to the alcohol consumed in each context. Results demonstrate that it is essential to consider situational and social characteristics of substance use contexts to better understand adolescent simultaneous use of alcohol and drugs and problems.

Purpose This study investigates the associations between tobacco outlet density, local tobacco policy, and youth smoking. A primary focus is on whether local tobacco policy moderates the relation between outlet density and youth smoking. Methods 1,491 youth (51.9% male, M age = 14.7 years, SD =1.05) in 50 midsized California cities were surveyed through a computer-assisted telephone interview. Measures of local clean air policy and youth access policy were created based on a review of tobacco policies in these cities. Outlet density was calculated as the number of retail tobacco outlets per 10,000 persons and city characteristics were obtained from 2000 U.S. Census data. Results Using multilevel regression analyses controlling for city characteristics, tobacco outlet density was positively associated with youth smoking. No significant main effects were found for the two tobacco policy types on any of the smoking outcomes after controlling for interactions and covariates. However, statistically significant interactions were found between local clean air policy and tobacco outlet density for ever smoked and past-12-month cigarette smoking. Comparisons of simple slopes indicated that the positive associations between tobacco outlet density and youth smoking behaviors were stronger at the lowest level of local clean air policy compared to the moderate and high levels. Conclusions Our results suggest that outlet density is related to youth smoking. In addition, local clean air policy may act as a moderator of relationship between outlet density and youth smoking, such that density is less important at moderate and high levels of this tobacco policy.

These findings suggest that exposure to tobacco outlets near home environments may be important for understanding adolescents' past-month smoking. Restricting access to tobacco outlets and controlling the number of outlets in residential areas may be an effective preventive strategy to help reduce adolescents' smoking.

This study investigated the associations of youth cigarette smoking with tobacco outlet densities and proximity of tobacco outlets to youth homes and schools across different buffers in 45 midsized California communities. The sample comprised 832 youth who were surveyed about their smoking behaviors. Inclusion criteria included both home and school addresses within city boundaries. Observations in the 45 cities were conducted to document addresses of tobacco outlets. City- and buffer-level demographics were obtained and negative binomial regression analyses with cluster robust standard errors were conducted. All models were adjusted for youth gender, age, and race. Greater densities of tobacco outlets within both a 0.75-mile and 1-mile buffer of youth homes were associated with higher smoking frequency. Neither tobacco outlet densities around schools nor distance to the nearest tobacco outlet from home or school were associated with youth past-30-day smoking frequency. Lower population density and percent African American in areas around homes, and lower percent unemployed in areas around schools were associated with greater smoking frequency. Results of this study suggest that restricting outlet density within at least 1-mile surrounding residential areas will help to reduce youth smoking.