The interactive effect of location, alcohol consumption and non-traffic injury

Insights into the context of simultaneous alcohol and cannabis use among young adults

Simultaneous alcohol and cannabis use (simultaneous use) is common among young adults and is associated with a greater number of substance use-related consequences compared to single substance use. Understanding what drives simultaneous use among young adults is crucial. This study aimed to gather qualitative data on physical, social, and situational characteristics of simultaneous use among young adults. Participants were 36 heavy drinking young adults (Mage = 21.79) who engaged in simultaneous use at least twice during the past 30 days. Individual semistructured interviews were conducted via Zoom videoconferencing. Thematic analyses were used to analyze interview data. Findings indicated that young adults are selective of where and with whom they engage in simultaneous use with. Physical characteristics associated with simultaneous use included being in familiar and safe locations. Young adults were less likely to engage in simultaneous use in public spaces. Social characteristics associated with simultaneous use included being at parties, being around close peers, and if others are approving of and/or also using alcohol and cannabis so their effects overlap. Being around family or being alone decreased the likelihood of simultaneous use. Situational characteristics associated with simultaneous use included having access to alcohol and/or cannabis, being a weekend and/or evening, pregaming, and using cannabis at the end of a drinking occasion. Young adults based their decision to engage in simultaneous use on a range of physical, social, and situational contextual factors. Future research should examine multiple characteristics of the context in order to identify specific context with an increased risk of simultaneous use. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Quantifying risk of injury from usual alcohol consumption: An instrumental variable analysis

BACKGROUND

Numerous studies of roadside accidents among emergency room patients show elevated risk of injury from acute alcohol consumption, i.e., recent drinking precedes the injury event. The observed effects are large and show a dose-response relationship. In contrast, studies quantifying the association between injury risk and chronic consumption, such as past-year average volume, show lower relative risk estimates than those from acute consumption.

METHODS

Combining data from 4 waves of US National Alcohol Surveys (NAS) for years 2000-2015 (N = 29,571, 53% overall cooperation rate), we estimated the risk of any past-year injury from past-year volume using logistic regression. This was contrasted with an instrumental variable (IV) analysis utilizing a 2-stage residual inclusion (2SRI) approach to estimate injury risk from volume, which adjusted for unobserved confounders using state beer and spirits tax rates, zip code-level outlet and bar density, and control state status as instruments.

RESULTS

Based on the combined US population surveys and controlling for sociodemographics, using conventional logistic regression, the odds ratios of injury from an average volume of 1, 2, and 5 drinks per day were 1.12 [95% confidence interval: 1.02, 1.24], 1.10 [1.00, 1.22], and 1.04 [0.88, 1.22], respectively. These compared with 1.67 [1.00, 2.78], 2.38 [0.87, 6.54], and 6.98 [0.57, 85.89] using the IV method. The proportion of injury attributed to alcohol also increased in magnitude, from 6.2% [0.3%, 11.9%] using the conventional approach to 17.9% [8.2%, 27.7%] using the IV method.

CONCLUSIONS

The association between injury and chronic alcohol consumption may be confounded by unobserved factors, resulting in a possible downward bias of the risk estimate.