Aims We investigated associations between the density of medical marijuana dispensaries (MMDs) around young adults' homes and marijuana use outcomes. Design Secondary data analysis. Setting Los Angeles County, CA, USA. Participants A total of 1887 participants aged 18–22 years, surveyed online in 2016–17. Measurements Outcomes were past‐month marijuana use (number of days used, number of times each day), positive expectancies and perceived peer use. Density was measured as the total number of MMDs and number of MMDs with storefront signage indicative of marijuana sales, within 4 miles of respondents' homes. Findings Eighty‐four per cent of respondents had 10 or more MMDs within 4 miles of their homes. Multiple linear regression analyses that adjusted for individual‐level socio‐demographic characteristics and neighborhood socio‐economic status indicated that living near a higher number of MMDs was associated with greater number of days used in the past month [β = 0.025; 95% confidence interval (CI) = 0.001, 0.049; P = 0.04] and higher positive marijuana expectancies (β = 0.003; 95% CI = 0.001, 0.007; P = 0.04). Living near more MMDs with storefront signage had a four‐ to six‐fold larger effect on number of times used per day and positive expectancies, respectively, compared with associations with the total MMD count. Adjusting for medical marijuana card ownership attenuated the association with number of days used in the past month and positive expectancies, and an unexpected association emerged between higher MMD density and fewer number of times used each day (β = −0.005; 95% CI = –0.009, −0.001; P = 0.03). Conclusions For young adults in Los Angeles County, living near more medical marijuana dispensaries (MMDs) is positively associated with more frequent use of marijuana within the past month and greater expectations of marijuana's positive benefits. MMDs with signage show stronger associations with number of times used each day and positive expectancies.

Background An increasing number of states have laws for the legal sale of recreational and medical cannabis out of brick-and-mortar storefront locations. Given the proliferation of cannabis outlets and their potential for impact on local economies, neighborhood structures, and individual patterns of cannabis use, it is essential to create practical and thorough methods to capture the location of such outlets for research purposes. However, methods used by researchers vary greatly between studies and often do not include important information about the retailer’s license status and storefront signage. Objective The aim of this study was to find methods for locating and observing cannabis outlets in Los Angeles County after the period when recreational cannabis retailers were granted licenses and allowed to be open for business. Methods The procedures included searches of online cannabis outlet databases, followed by methods to verify each outlet’s name, address, license information, and open status. These procedures, conducted solely online, resulted in a database of 531 outlets. To further verify each outlet’s information and collect signage data, we conducted direct observations of the 531 identified outlets. Results We found that 80.9% (430/531) of these outlets were open for business, of which 37.6% (162/430) were licensed to sell cannabis. Unlicensed outlets were less likely to have signage indicating the store sold cannabis, such as a green cross, which was the most prevalent form of observed signage. Co-use of cannabis and tobacco/nicotine has been found to be a substantial health concern, and we observed that 40.6% (175/430) of cannabis outlets had a tobacco/nicotine outlet within sight of the cannabis outlet. Most (350/430, 81.4%) cannabis outlets were located within the City of Los Angeles, and these outlets were more likely to be licensed than outlets outside the city. Conclusions The findings of this study suggest that online searches and observational methods are both necessary to best capture accurate and detailed information about cannabis outlets. The methods described here can be applied to other metropolitan areas to more accurately capture the availability of cannabis in an area.

Background Neighborhood factors reported subjectively by residents and measured objectively at the census tract are both associated with adolescent alcohol, cigarette, electronic cigarette (e-cigarette), and marijuana (ATOD) use. Less clear is how these neighborhood factors are longitudinally associated with each substance. Equivocal findings may be due to lack of consideration of individual, peer, and family effect modifiers, which could help adolescents overcome exposure to stressful neighborhood environments. Methods We used multivariate logistic regressions with interaction terms to test whether parental monitoring, resistance self-efficacy (RSE) and being around peers who use ATOD modified the association between four subjective and objective neighborhood measures and odds of using each substance measured one year later among 2,539 high school students and college freshmen originally recruited from middle schools in Southern California. Results Census tract-level disadvantage was not longitudinally associated with ATOD use. However, perceptions of higher neighborhood disorganization, less social cohesion, and more neighborhood problems with alcohol and drug use were associated with higher odds of ATOD use. Higher RSE and weaker affiliations with peers who use ATOD consistently buffered negative effects of neighborhood disorganization and neighborhood problems with alcohol and drugs on past year ATOD use. Conclusions Community-level programs that increase social cohesion among neighbors, neighborhood monitoring of deviant behaviors, and better policing of open drug selling may prevent ATOD use. Programs should also target RSE and minimize affiliations with peers who use ATOD, which could reduce the magnitude of the association with ATOD, even for adolescents living in the most at-risk neighborhoods.

Background and Objectives To expand on epidemiologic studies examining associations between the legalization of recreational cannabis and use among young adults, we examined the associations between licensed and unlicensed cannabis outlet density and cannabis outcomes. Methods A total of 1097 young adults aged 21 and older living in Los Angeles County were surveyed before licensed recreational cannabis outlets opened (Time 1: July to December 2017) and after (Time 2: July 2018 to June 2019). Using a database of open licensed and unlicensed cannabis retailers to calculate individual‐level cannabis outlet density measures, we examined associations between outlet density within a 4‐mile radius of participants’ residences with Time 2 outcomes of any past‐month use, daily use, intentions to use, quantity used, consequences, and cannabis use disorder (CUD) symptoms. Results After controlling for demographic factors and cannabis outcomes at a time point prior to their opening (Time 1), licensed cannabis outlets were associated with young adults’ cannabis use, heavy use, and intentions, and unlicensed outlets were associated with young adults’ heavy cannabis use and CUD symptoms. Conclusion and Scientific Significance This study expands beyond studies of outlet prevalence to find that, after controlling for outcomes 1 year prior, licensed and unlicensed outlets were associated with young adults’ cannabis outcomes. The current study is among the first to find associations between cannabis use outcomes and density of cannabis outlets among young adults using data from two time points: preopening and postopening of recreational cannabis retailers. Findings can inform policies around the density and placement of cannabis outlets. (Am J Addict 2020;00:00–00)

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Objectives.-The purpose of this paper is to describe the 4-step process (consent, selection, protection, and abstraction) of acquiring a large sample of chiropractic patient records from multiple practices and subsequent data abstraction.Methods.-From April 2017 to December 2017 RAND acquired patient records from 99 chiropractic practices across the United States. The records included patients enrolled in a survey e study (prospective sample) and a random sample of all clinic patients (retrospective sample) with chronic back or neck pain. Clinic staff were trained to collect the sample, scan, and transfer the records We designed an on-line data collection tool for abstraction. Protocols were instituted to protect patient confidentiality. Doctors of chiropractic were selected and trained as abstractors, and a system was established to monitor data collection.Results.-In compliance with data protection protocols, 3,603 patient records were scanned, including 1,475 in the prospective sample and 2,128 in the random sample. A total of 1,716 patients (prospective sample) consented to having their records scanned, but only 1,475 could be retrieved. Of records scanned, 19 percent were unusable due to illegibility, no care during the period of interest, or poor scanning. The abstractor inter-rater reliability for appropriateness of care decisions was fair to moderate (kappa .38-.48).

Physical activity (PA) tends to decline with age, but changes are influenced by individual and contextual factors. Identifying the relative contributions of each may be useful in addressing inactivity. We studied the degree to which changes in the built environment were associated with changes in PA among young women maturing from adolescence to adulthood. We followed a cohort of young women who participated in the Maryland site of the Trial of Activity of Adolescent Girls in 11th grade (ages 16-17 years) and again at ages 22 to 23. Participants wore accelerometers for 1 week in 2009 and in 2015 and answered questionnaires about their daily lives. We found that living closer to mass transit, sports, and recreational facilities was associated with more moderate-to-vigorous physical activity (MVPA). Individual-level factors were strongly associated with MVPA as well.