Abstract
PURPOSE
To examine the availability of medical marijuana dispensaries, price of medical marijuana products, and variety of medical marijuana products in school neighborhoods and their associations with adolescents’ use of marijuana and susceptibility to use marijuana in the future.
METHODS
A representative sample of 8th, 10th, and 12th graders (N=46,646) from 117 randomly selected schools in California participated in the cross-sectional 2015-16 California Student Tobacco Survey (CSTS). Characteristics of medical marijuana dispensaries in California were collected and combined with school locations to compute availability, price, and product variety of medical marijuana in school neighborhoods. Multilevel logistic regressions with random intercepts at school level were conducted to test the associations, accounting for individual and school socioeconomic characteristics.
RESULTS
The distance from school to the nearest medical marijuana dispensary (within 0-1 mile and 1-3 mile bands) was not associated with adolescents’ use of marijuana in the past month or susceptibility to use marijuana in the future, nor was the weighted count of medical marijuana dispensaries within the 3-mile band of school. Neither the product price nor the product variety in the dispensary nearest to school was associated with marijuana use or susceptibility to use. The results were robust to different specifications of medical marijuana measures.
CONCLUSIONS
There was no evidence supporting the associations of medical marijuana availability, price, or product variety around school with adolescents’ marijuana use and susceptibility to use.
Keywords: medical marijuana dispensary, school neighborhood, adolescent health, drug abuse
INTRODUCTION
In recent years, the proportion of adolescents who use marijuana has surpassed the proportion who smoke cigarettes in the U.S. In 2016, the Monitoring the Future survey estimated that the national prevalence of past-month marijuana use among 8th, 10th, and 12th graders was 5.4%, 14.0%, and 22.5%, respectively.1 Early initiation of marijuana use is linked to a wide range of negative health consequences and socioeconomic outcomes.2-6 Preventing experimentation of marijuana and regular marijuana use among adolescents has become a public health priority.7
The increase in marijuana use in adolescents coincided with the increasing number of states passing medical marijuana laws, a common provision of which is the protection of medical marijuana dispensaries.8 Although providing marijuana for medical use in dispensaries usually requires additional scrutiny for patients under age 18, there are concerns that adolescents could be still influenced by the presence of dispensaries in the neighborhood. Medical marijuana dispensaries may increase adolescents’ access to marijuana, normalize their attitudes towards marijuana use, and expose them to marketing tactics. Unlike state-wide law provisions which allow for possession and cultivation, patient registry system, and approval of certain medical conditions,9 the location and density of medical marijuana dispensaries are usually subject to city or county licensing policies and zoning ordinances.10 The huge variations in these local regulations across and within states have contributed to variations in the availability of medical marijuana dispensaries in neighborhoods, which may potentially generate differential influences on adolescents’ marijuana use behaviors.
Despite the strong relationship between retail outlets and alcohol and tobacco use documented by a number of studies,11-14 examination of the associations of medical marijuana dispensaries with marijuana use remains limited. The existing research on state-wide laws provide little insight into within-state spatial variations. The dearth of research at the neighborhood level is largely due to a lack of data associating geographic locations with individuals. Even when location data such as zip code and city were available, exact point address was unknown. To date, only three studies have provided empirical evidence at the neighborhood level and all of them defined neighborhood broadly as zip code or city. Two California studies on adults reported that higher prevalence of adults’ marijuana use and abuse in cities/zip codes was associated with higher density of dispensaries.15,16 In contrast, the one study on adolescents approximated school point locations with zip code centroids and found that the presence of dispensaries around schools was not associated with past-month use of marijuana among adolescents.17 City or zip code level measures may be too crude to represent neighborhood characteristics that influence the daily life of individuals. A narrowly defined neighborhood is particularly meaningful to adolescents who drive vehicles less often than adults do.
Using point location measures, this study aimed to ascertain whether the availability, price, and product variety of medical marijuana in school neighborhoods were associated with adolescents’ use of marijuana and susceptibility to use marijuana in the future. The study utilized a representative sample of adolescents in California, the state with the longest history of medical marijuana legalization and the largest number of dispensaries and registered patients.18
METHODS
STUDY SAMPLE
Funded by the California Department of Public Health, the 2015-16 California Student Tobacco Survey (CSTS) is a cross-sectional survey to collect data on tobacco and other drug use, including marijuana use behaviors. CSTS has been conducted approximately every two years since 2001-02. The 2015-16 wave was administered by the University of California, San Diego between October 2015 and June 2016. A two-stage random stratified sampling design was employed, which randomly selected public and non-sectarian schools from regions in the first stage and invited all classrooms in a grade to participate in the second stage. When a school was not able to recruit all classrooms (23% of schools), classrooms within a grade were randomly sampled.
The survey was self-administered on paper by 14% of schools and online by 86% of schools. Both English and Spanish versions were available to students. Consent procedures included obtaining the appropriate parental/guardian consent (using passive or active consent, as dictated by the school district) and students providing assent. The survey was approved by the Human Research Protections Program at the University of California, San Diego (#150256) and the California State Committee for the Protection of Human Subjects (#15-04-1992).
A total of 119 schools participated in the CSTS 2015-16 survey, representing 45% of schools initially contacted. Among schools that responded, the minimal acceptable response rate for students was set at 30%. Two schools had a lower than 30% students responded and were excluded, leaving 117 in the dataset. The mean response rate for students from these schools was 75.5% and the median was 79.2%. Our analysis focused on students who were 8th, 10th and 12th graders in the survey (N=47,981). The final analyses excluded 1,335 students (2.8%) with incomplete information, resulting in effective sample size of 46,646 students. The overall racial and ethnic distribution of the study sample was similar to the student profile provided by the Department of Education for all the students in California.19
MEASURES
Outcome Measures: Marijuana Use and Susceptibility to Use
The individual-level outcome variables included two dichotomized indicators assessing 1) whether an adolescent was a current marijuana user, and 2) if not identified as a current marijuana user, whether an adolescent was susceptible to use marijuana in the future. Current marijuana use was defined as using marijuana (including blunts) in the past month. Susceptibility has been a strong indicator for future use in the tobacco control literature.20 We used one of the three items that were validated for assessing susceptibility in smokers and adapted it to assess susceptibility to marijuana use.21 Specifically, adolescents who had not used marijuana in the past month (non-users) were classified as being susceptible to use marijuana if their response to the question “if one of your best friends offered you marijuana (including blunts), would you use it?” was “definitely yes”, “probably yes”, or “probably not”. Only adolescents who responded with the strongest negative response “definitely not” were classified as not being susceptible to marijuana use.
Primary Explanatory Measures: Medical Marijuana Availability, Price, and Product Variety
The school-level explanatory measures of interest were a series of variables representing the availability, price, and variety of medical marijuana products in school neighborhoods. We obtained exact street addresses, price, and detailed product information for all medical marijuana dispensaries with storefronts in California from a previously validated crowdsourced website (weedmaps.com),15 which posts the most up-to-date information voluntarily contributed by dispensary owners and marijuana users. The dispensary data were compiled in March-June, 2016. A total of 994 dispensaries with storefronts were listed on weedmaps.com during the data collection period. We removed 52 dispensaries (5%) that lacked exact street addresses. Point locations of the remaining 942 dispensaries were successfully geocoded using ArcGIS (ArcMap, Version 10.4; ESRI Inc., Redlands, CA, USA).
A school’s availability of medical marijuana dispensaries was measured by the proximity to the nearest dispensary and the density of dispensaries within the neighborhood. Specifically, 0-1 and 1-3 mile bands around the school street address were created using Euclidean (straight-line) method. The 0-1 mile band is commonly used in literature to represent walkable distance to retailers such as tobacco, alcohol and food outlets.22-26 Because the density of medical marijuana dispensaries is far less than that of tobacco or alcohol outlets,17 we also chose the 1-3 mile band to increase statistical power, which represents a range of distance easily reachable by bicycle, vehicle, or public transportation. The point locations of medical marijuana dispensaries were spatially joined with the 0-1 and 1-3 mile bands around the school locations. Two dichotomized indicators were generated to represent the proximity of the nearest dispensary: less than 1 mile and between 1 and 3 miles from school, respectively. One continuous variable was created to represent the density of dispensaries in the 0-3 mile band. To account for the ease of access to dispensaries, the count of dispensaries within different distances were given different weights, with a weight of 1 for those within 1-mile, 0.75 for those between 1 and 2 miles, and 0.5 for those between 2 and 3 miles.27 The weighted count was computed as the sum of dispensaries with the corresponding weights. In sensitivity analyses, we also considered the nearest distance in the 0-1, 1-2, and 2-3 mile bands, unweighted count of dispensaries in the 0-1, 1-2, and 2-3 mile bands, and unweighted count of dispensaries within the 0-3 mile band.
The price of marijuana was measured by the lowest unit price of one eighth ounce of all marijuana flower products in the dispensary nearest to a school. Marijuana flower products included all strains of the three types: Indica, Sativa, and Hybrid. The unit of one eighth ounce (approximately 3.5 grams or 5 joints worth) was selected to represent the most popular quantity purchased in marijuana dispensaries.28 Non-flower products, such as extract, edible, drink, pre-roll, and topicals, were not considered due to the lack of standard quantity measures. Detailed product information was not available for 4 dispensaries; we filled in missing values with the average value in the dispensary‘s county. As a robustness check, we also considered the highest unit price of one eighth ounce of all marijuana flower products.
The variety of marijuana products was measured by the total count of marijuana strains in flower-type products in the dispensary nearest to a school. Missing information for the 4 dispensaries was replaced with the average value in the dispensary’s county. The number of non-flower products were added to the total count in the sensitivity analyses.
Individual Socioeconomic Measures
The individual-level variables included student grades, gender, race/ethnicity, earning money from a job or obtaining allowance from parents or guardians during an average week, and having friends who use marijuana.
School Contextual Measures
The contextual variables included those that have been shown to be correlated with marijuana use.8,16 For the 117 unique census tracts of the schools, the following socioeconomic measures were obtained from the American Community Survey, 2015 5-year estimates: population density computed as thousand population per square mile, proportion of population under age 18, proportion of population that were not non-Hispanic White, and median household income in thousand dollars. Using 2010 rural-urban commuting area codes,29 an indicator was generated for metropolitan core area. Count of tobacco outlets within the 0-1 mile band around school locations was obtained from infoUSA, a commercial provider of business lists with moderate specificity and sensitivity.30,31 We used North American Industry Classification System codes 445310, 722410, 445120, 447190, 445110, 453991, 447110, 452112, 452910, and 451212 to identify tobacco outlets.
STATISTICAL ANALYSIS
Descriptive statistics were provided for individual and school level variables. To account for the hierarchical structure of study sampling, we used multilevel logistic regressions with random intercepts at the school level to examine the associations, controlling for individual and school socioeconomic factors. Sensitivity analyses were performed to test the robustness of findings to different specifications of medical marijuana availability, price, and product variety measures. We applied survey sampling weights to reported statistics to account for multistage sampling and varying probability of sample selection in the 2015-16 CSTS survey. The statistical analyses were conducted in STATA 14 (STATA Corp, College Station, TX).
RESULTS
DESCRIPTIVE STATISTICS
Among the 46,646 adolescents sampled in California, 11.3% (95%CI: 10.9-11.8%) used marijuana in the past month. The prevalence for 8th, 10th, and 12th graders was 3.50%, 11.43%, and 18.44%, respectively, slightly smaller than the national estimates of 5.4%, 14.0%, and 22.5% in the 2016 Monitoring the Future survey.1 Among those who did not use marijuana in the past month, 28.65% (95%CI: 27.94-29.35%) were susceptible to use marijuana in the future.
The mean distance between school and the nearest medical marijuana dispensary was 8.18 miles (95%CI: 6.03-10.34) and the median was 3.69 miles. About 15.38% and 30.76% schools had the nearest dispensary located within 1 mile and 1-3 miles, respectively. The mean of weighted count of dispensaries in the 0-3 mile band was 1.89 (95%CI: 1.16-2.62) and the median was 0. About 16.23% of schools had a weighted count of dispensaries between 0 and 1, and 29.91% had a weighted count greater than 1. The mean of the lowest price of marijuana flower products in the nearest dispensary was $23.70 per one eighth ounce and the mean of the highest price was $76.54. The average total number of marijuana strains in the nearest dispensaries was 33.10.
MULTILEVEL LOGISTIC REGRESSION RESULTS
The proximity and density of medical marijuana dispensaries were examined in multilevel regressions and are shown in Table 2 and Table 3, respectively. Having the nearest dispensary located within 0-1 mile or 1-3 mile bands from a school was not associated with adolescents’ marijuana use in the past month or their susceptibility to use in the future. Similarly, the weighted count of medical marijuana dispensaries in the 3-mile band was not associated with marijuana use or susceptibility to use.
Table 2.
Associations of Proximity of Medical Marijuana Dispensaries with Marijuana Use and Susceptibility to Use. CSTS 2015-16 (N=46,646)
| Characteristics | Odds Ratio (95% CI)
|
|
|---|---|---|
| Marijuana Use | Susceptibility to Use among Non-users | |
|
| ||
| Proximity of Medical Marijuana Dispensaries | ||
| Distance to the nearest dispensary | ||
| <=1 mile | .88 (.72,1.07) |
1.08 (.96,1.23) |
| 1-3 mile | .94 (.80,1.09) |
1.01 (.92,1.11) |
| >3 mile (reference) | 1 | 1 |
|
| ||
| Student Characteristics | ||
| Grade | ||
| 8th grade (reference) | 1 | 1 |
| 10th grade | 1.87*** (1.54,2.27) |
1.42*** (1.28,1.57) |
| 12th grade | 3.04*** (2.51,3.68) |
1.52*** (1.37,1.69) |
| Male | 1.18*** (1.12,1.25) |
.93** (.89,.98) |
| Race/ethnicity | ||
| Non-Hispanic White (reference) | 1 | 1 |
| Non-Hispanic Black | 1.04 (.90,1.21) |
1.03 (.91,1.17) |
| Hispanic | .92* (.86,.99) |
1.14*** (1.07,1.21) |
| Non-Hispanic Asian | .42*** (.36,.48) |
.84*** (.77,.92) |
| Other | .88 (.74,1.04) |
.97 (.85,1.11) |
| Having earnings or allowance | 1.80*** (1.68,1.93) |
1.19*** (1.13,1.25) |
| Any friend using marijuana | 23.50*** (19.43,28.43) |
5.76*** (5.43,6.11) |
|
| ||
| School Characteristics | ||
| Tract population density | 1.00 (.98,1.02) |
.99 (.98,1.00) |
| Tract population under age 18 | .98 (.97,1.00) |
.99 (.98,1.00) |
| Tract racial/ethnic minority composition | .99 (.99,1.00) |
1.00 (.99,1.00) |
| Tract median household income | .99 (.99,1.00) |
1.00 (.99,1.00) |
| Tract in metropolitan core area | 1.05 (.83,1.34) |
.97 (.83,1.12) |
| Count of tobacco outlets within 1-mile buffer of schools | .99 (.99,1.00) | 1.00 (.99,1.00) |
p<.05,
p<.01,
p<.001
Table 3.
Associations of Density of Medical Marijuana Dispensaries with Marijuana Use and Susceptibility to Use. CSTS 2015-16 (N=46,646)
| Odds Ratio (95% CI)
|
||
|---|---|---|
| Marijuana Use | Susceptibility to Use among Non-users | |
|
| ||
| Density of Medical Marijuana Dispensaries | ||
| Weighted count of dispensaries in 0-3 mile band around school | ||
| =0 (reference) | 1 | 1 |
| >0 and <=1 | .91 (.76,1.09) |
1.03 (.93,1.15) |
| >1 | .93 (.78,1.10) |
1.03 (.93,1.14) |
|
| ||
| Student Characteristics | ||
| Grade | ||
| 8th grade (reference) | 1 | 1 |
| 10th grade | 1.88*** (1.55,2.28) |
1.41*** (1.27,1.57) |
| 2th grade | 3.05*** (2.52,3.70) |
1.52*** (1.37,1.69) |
| Male | 1.18*** (1.12,1.25) |
.93** (.89,.98) |
| Race/ethnicity | ||
| Non-Hispanic White (reference) | 1 | 1 |
| Non-Hispanic Black | 1.04 (.90,1.21) |
1.03 (.91,1.17) |
| Hispanic | .92* (.85,.99) |
1.14*** (1.07,1.21) |
| Non-Hispanic Asian | .42*** (.36,.48) |
.84*** (.77,.92) |
| Other | .88 (.74,1.04) |
.97 (.85,1.11) |
| Having earnings or allowance | 1.80*** (1.68,1.93) |
1.19*** (1.13,1.25) |
| Any friend using marijuana | 23.50*** (19.43,28.43) |
5.76*** (5.43,6.11) |
|
| ||
| School Characteristics | ||
| Tract population density | 1.00 (.98,1.02) |
.99 (.98,1.00) |
| Tract population under age 18 | .98 (.97,1.00) |
.99 (.98,1.00) |
| Tract racial/ethnic minority composition | .99 (.99,1.00) |
1.00 (.99,1.00) |
| Tract median household income | .99 (.99,1.00) |
1.00 (.99,1.00) |
| Tract in metropolitan core area | 1.05 (.83,1.34) |
.97 (.83,1.12) |
| Count of tobacco outlets within 1-mile buffer of schools | .99 (.99,1.00) |
1.00 (.99,1.00) |
p<.05,
p<.01,
p<.001
Further, we found no associations of marijuana use or susceptibility to use with the price or the variety of marijuana flower products in the dispensary nearest to the school (detailed results are not shown).
Several individual factors had consistent associations with the outcome variables. Adolescents who were older, had pocket money, or had friends who used marijuana were more likely to use marijuana or to be susceptible to use marijuana in the future (p’s<.001). Non-Hispanic Asians were less likely to use or to be susceptible to use marijuana compared to non-Hispanic Whites (p<.001). Males were more likely to use marijuana than females and Hispanics were less likely to use marijuana than non-Hispanic Whites. Among non-users, however, males were less likely and Hispanics were more likely to be susceptible to use marijuana. None of the school level contextual factors was associated with the outcome variables.
SENSITIVITY ANALYSIS RESULTS
A series of sensitivity analyses were conducted. We considered to replace the medical marijuana measures with: 1) the nearest dispensary located in the 0-1, 1-2, and 2-3 mile bands, 2) the unweighted count of dispensaries in the 0-1, 1-2, and 2-3 mile bands, 3) the unweighted count of dispensaries within the 0-3 mile band, 4) the highest price of one eighth ounce of marijuana flower products, and 5) the count of marijuana products including non-flower types. Consistent with findings reported above, none of these measures had associations with adolescents’ marijuana use or susceptibility to use (detailed results are not shown).
DISCUSSION
This study examined the contextual associations of medical marijuana dispensaries with marijuana use behaviors in a representative sample of adolescents in California. We reported null associations of the proximity and density of medical marijuana dispensaries in school neighborhoods with adolescents’ marijuana use and susceptibility to use. Compared with the nation-wide study that found similar results using zip code centroid to approximate school locations,17 this California study was able to use school street address to calculate more precise proximity and density in a smaller school neighborhood within which retailers are easily accessible to adolescents. Such narrowly defined school neighborhood is the focal area for licensing and zoning policies that aim to create healthy environments for adolescents. The current study focused on past-month use instead of past-year use because the exact timing of past-year use was unknown and likely inconsistent with the timing of dispensary data collection. Price and variety of marijuana products were not assessed in the previous study17.
Another unique contribution of this study is the objective assessment of price and variety of medical marijuana products around schools. Previous research relied on crude expenditure and quantity measures from user’ self-report or police estimation of seized drugs to compute the price of illicit marijuana.32-34 Using detailed and objective marijuana product information, we found that price and product variety were not directly associated with adolescents’ marijuana use and susceptibility to use. However, competition from medical marijuana dispensaries could have reduced the price of marijuana on the street and adolescents’ marijuana use may be influenced indirectly. This possible mechanism is worth further investigation.
The lack of relationship between the availability of medical marijuana dispensaries and marijuana use behaviors among the adolescent population is inconsistent with previous research on the adult population.15,16 This discrepancy may be due to medical marijuana dispensaries not being the primary source of marijuana for adolescents. Parental consent is required for patients under age 18 and an identification check and doctor’s recommendation are required to purchase medical marijuana from dispensaries in California. In addition, some cities and counties in California prohibit operating dispensaries within 1,000 feet of schools, playgrounds, or youth centers.10 These regulations make direct provision and marketing of medical marijuana products less accessible to adolescents. Adolescents may still be exposed to marijuana through third-party purchases, but the increase in access is likely small because of the small percentage of registered patients among all marijuana users. The current study was not able to test these hypotheses and further studies are warranted to examine the underlying mechanisms of the study findings.
The lack of associations between retail outlets and product use among adolescents is also observed by some, although not all, studies on other products, such as tobacco, alcohol, and food.13,24,35-38 Compared to these products, the influences of retail outlets on adolescents’ marijuana use may be smaller because underage consumption of marijuana remains illegal. Our study is the second of the kind that focuses on adolescents.17 We hope future studies could replicate it using other study samples to substantiate the findings. Particularly, studies are encouraged to collect data on California samples after January 1st, 2018 when the retail sale of marijuana became legal.
Despite a number of strengths, this study has a few limitations. First, as in previous studies, this study provided a cross-sectional examination without inferring causal relationships. Second, self-report of marijuana use may be subject to reporting bias. Third, the mode of marijuana use (e.g., smoking, vaping, edibles) and sources of marijuana were not assessed in the 2015-16 CSTS survey. Medical and recreational marijuana use were not differentiated. However, medical marijuana use in this age group is very rare,39 therefore the study findings should largely represent marijuana use for recreational purpose. Fourth, the 2015-16 CSTS survey did not sample private schools or continuation schools or other alternative schools. The findings may not be generalizable to students who enrolled in these schools or schools outside of California or to those who dropped out of school. In addition, the mode of transportation was not assessed in the survey, which may influence the access to dispensaries. Due to data limitation, we were not able to examine dispensary-related environments beyond spatial access, such as point-of-sale promotions and advertising, and perceived access and harms. Lastly, a single data source may not provide an exhaustive list of dispensaries. We only considered dispensaries with storefronts and excluded those only providing delivery services. Contextual influences of dispensaries around adolescents’ home were not considered either.
In light of the study limitations, the results of this study on adolescents should be interpreted with caution. It should not be used as evidence against marijuana regulation strategies such as licensing, zoning ordinances, taxation, or policies to limit product type. Instead, the findings illustrate the current state of the medical marijuana environment. On November 8th 2016 California passed the laws to legalize marijuana for recreational use (Proposition 64) and on January 1st 2018 retail sales of marijuana became legal. Efforts are being made to integrate the existing medical marijuana system into the new legalization. These changes in the policy landscape are likely to modify neighborhood contexts associated with marijuana, and findings of this study represent a baseline for the evolving environment that accompanies the change in regulation.
CONCLUSION
We did not find empirical support of the associations of medical marijuana availability, price, and product variety around schools with adolescents’ marijuana use and susceptibility to use. Efforts should be taken to monitor changes in contextual environments of marijuana use in the new scheme of recreational marijuana legalization and examine the causal effects of these contextual factors to better inform policymaking.
Table 1.
Summary Statistics: Students, Medical Marijuana Dispensaries, Schools, and Census Tracts. CSTS 2015-16 (N=46,646)
| Characteristics | Mean (95% CI) |
|---|---|
|
| |
| Sample size | |
| Schools (No.) | 117 |
| Students (No.) | 46,646 |
|
| |
| Characteristics of Medical Marijuana Dispensary | |
| Proximity: distance to the nearest dispensary (%) | |
| <=1 mile | 15.38 (8.74,22.01) |
| 1-3 mile | 30.76 (22.28, 39.25) |
| >3 mile | 53.84 (44.67, 63.01) |
| Density: weighted count of dispensaries in 3-mile buffer (%) | |
| =0 | 53.84 (44.67, 63.01) |
| >0 and <=1 | 16.23 (9.45, 23.02) |
| >1 | 29.91 (21.49, 38.33) |
| Price ($) | |
| Lowest price of flower products in the nearest dispensary | 23.70 (21.93, 25.47) |
| Product Variety | |
| Count of marijuana strains in the nearest dispensary (No.) | 33.10 (30.00, 36.21) |
|
| |
| Student Characteristics | |
| Grade (%) | |
| 8th grade | 29.11 (28.34, 29.88) |
| 10th grade | 36.82 (36.13, 37.50) |
| 12th grade | 34.06 (33.40, 34.72) |
| Male (%) | 50.61 (49.87, 51.35) |
| Race/ethnicity (%) | |
| Non-Hispanic White | 26.26 (25.61, 26.92) |
| Non-Hispanic Black | 5.68 (5.26, 6.10) |
| Hispanic | 54.00 (53.26, 54.74) |
| Non-Hispanic Asian | 12.64 (12.18, 13.10) |
| Other | 1.39 (1.22, 1.56) |
| Having earnings or allowance (%) | 62.29 (61.57, 63.01) |
| Any friend using marijuana (%) | 61.30 (60.57, 62.04) |
|
| |
| School Characteristics | |
| Tract population density (thousand/mile2) | 5.85 (5.05, 6.64) |
| Tract population under age 18 (%) | 24.48 (23.35, 25.61) |
| Tract racial/ethnic minority composition (%) | 61.45 (57.22, 65.68) |
| Tract median household income (thousand $) | 68.97 (63.34, 74.59) |
| Tract in metropolitan core area (%) | 92.30 (87.40, 97.20) |
| Count of tobacco outlets within 1-mile buffer of schools (No.) | 21.67 (19.01, 24.33) |
Implications and Contribution.
There are concerns that adolescents could be influenced by medical marijuana dispensaries in the neighborhood. Linking dispensaries with schools through precise location measures, this study found no empirical support of associations of medical marijuana availability, price, and product variety around schools with adolescents’ marijuana use and susceptibility to use.
Acknowledgments
Funding Source:
This work was supported by grant R01DA042290 (Shi) from the National Institute on Drug Abuse and grant #347564 (Zhu) from the California Department of Public Health’s Tobacco-Related Disease Research Program and the California Department of Education. The 2015-16 California Student Tobacco Survey was supported by a contract from the California Department of Public Health (Contract # 14-10383). These sponsors have no role in study design, collection, analysis, or interpretation of data; writing the report; or the decision to submit the report for publication.
Abbreviation
- CSTS
California Student Tobacco Survey
Footnotes
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Financial Disclosure:
The authors have no financial relationships relevant to this article to disclose.
Conflicts of Interest:
The authors have no conflicts of interest relevant to this article to disclose.
Contribution of Authors:
Dr. Shi conceptualized and designed the study, collected dispensary data, carried out the statistical analyses, drafted the initial manuscript, and reviewed and revised the manuscript. Dr. Cummins and Dr. Zhu designed the survey data collection instruments, coordinated and supervised survey data collection, and reviewed and revised the manuscript. All authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work.
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