Causal and Associational Language in Observational Health Research: A Systematic Evaluation.

We estimated the degree to which language used in the high-profile medical/public health/epidemiology literature implied causality using language linking exposures to outcomes and action recommendations; examined disconnects between language and recommendations; identified the most common linking phrases; and estimated how strongly linking phrases imply causality. We searched for and screened 1,170 articles from 18 high-profile journals (65 per journal) published from 2010-2019. Based on written framing and systematic guidance, 3 reviewers rated the degree of causality implied in abstracts and full text for exposure/outcome linking language and action recommendations. Reviewers rated the causal implication of exposure/outcome linking language as none (no causal implication) in 13.8%, weak in 34.2%, moderate in 33.2%, and strong in 18.7% of abstracts. The implied causality of action recommendations was higher than the implied causality of linking sentences for 44.5% or commensurate for 40.3% of articles. The most common linking word in abstracts was "associate" (45.7%). Reviewers' ratings of linking word roots were highly heterogeneous; over half of reviewers rated "association" as having at least some causal implication. This research undercuts the assumption that avoiding "causal" words leads to clarity of interpretation in medical research.

Sex differences in nonmedical prescription tranquilizer and stimulant use trends among secondary school students in Argentina, Chile, and Uruguay.

BACKGROUND: Little is known about recent nonmedical prescription tranquilizer and stimulant use trends in Latin America. We tested whether recent trends among students in three South American countries differed by sex over time. METHODS: Three countries independently collected National School Students Survey on Drugs. Students in 8th, 10th, and 12th grades were sampled in Argentina (2007-2014, N = 328,202), Chile (2007-2015, N = 136,379), and Uruguay (2007-2016, N = 32,371). Weighted linear regression models predicted the prevalences and trends over time of past-year nonmedical tranquilizer and stimulant use by country, and tested whether trends differed by sex, adjusting for school type and grade. RESULTS: In Argentina from 2007 to 2014, past-year nonmedical prescription tranquilizer (girls: 2.8 to 2.6%, boys: 2.5 to 2.3%) and stimulant (girls: 1.7 to 1.3%, boys: 1.9 to 1.5%) use trends did not differ by sex. In Chile from 2007 to 2015, nonmedical prescription tranquilizer use trends significantly differed comparing girls (3.9 to 10%) with boys (3.2 to 6.9%); stimulant use trends did not differ comparing girls (1.6 to 2.0%) with boys (2.0 to 1.3%). In Uruguay from 2007 to 2014 and 2014-2016, past-year nonmedical prescription tranquilizer (girls: 5.1 to 6.6%; boys: 2.8 to 4.2%) and stimulant (girls: 1.8 to 0.7%; boys: 1.8 to 0.7%) use trends did not differ by sex. CONCLUSIONS: Trends of nonmedical prescription tranquilizer use recently increased in Chile and Uruguay, widening by sex over time in Chile only. The drivers of increasing tranquilizer use among girls in Chile and Uruguay merit further investigation.

Investigating how perceived risk and availability of marijuana relate to marijuana use among adolescents in Argentina, Chile, and Uruguay over time.

AIMS: Amid changing marijuana policies in the Southern Cone, we examined relationships between marijuana-related risk factors and marijuana use among adolescents in Argentina, Chile, and Uruguay from 2001 to 2016. METHODS: Using cross-sectional surveys from 8th, 10th, and 12th graders and weighted time-varying effect models, we estimated associations between perceived risk (no/low risk versus moderate/great risk) and perceived availability (easy/very easy versus difficult/very difficult/not able to obtain) of marijuana, and any past-month marijuana use. RESULTS: In all countries, marijuana use increased over time and adolescents who perceived no/low risk and easy availability had higher odds of use. In Argentina, the bivariate risk/use association weakened from 2001 (OR = 15.24, 95%CI = 9.63, 24.12) to 2004 [OR = 3.86 (2.72, 5.48)] and strengthened until 2011 [OR = 8.22 (7.56, 10.30)]; the availability/use association strengthened from 2005 [OR = 5.32 (4.05, 6.98)] to 2009 [OR = 20.77 (15.57, 27.70)] and weakened until 2014 [OR = 11.00 (9.11, 13.27)]. In Chile, the risk/use association weakened from 2001 [OR = 7.22 (6.57, 7.95)] to 2015 [OR = 5.58 (4.82, 6.48)]; the availability/use association weakened from 2001 [OR = 5.92 (4.96, 7.06)] to 2015 [OR = 4.10 (3.15, 5.34)]. In Uruguay, the risk/use association weakened from 2003 [OR = 34.22 (22.76, 51.46)] to 2016 [OR = 6.23 (4.96, 7.83)]; the availability/use association weakened from 2005 [OR = 29.13 (13.39, 63.39) to 2007 [OR = 9.42 (3.85, 23.07)], and strengthened until 2016 [OR = 22.68 (12.03, 42.76)]. CONCLUSIONS: Overall, the association between risk and use weakened in all countries, suggesting risk perceptions became a weaker determinant of marijuana use. Perceived availability remained strongly associated with use and may become an increasingly important driver of use (particularly in Uruguay and Argentina).

Association Between Prescription Drug Monitoring Programs and Nonfatal and Fatal Drug Overdoses: A Systematic Review.

Background: Prescription drug monitoring programs (PDMPs) are a key component of the president's Prescription Drug Abuse Prevention Plan to prevent opioid overdoses in the United States. Purpose: To examine whether PDMP implementation is associated with changes in nonfatal and fatal overdoses; identify features of programs differentially associated with those outcomes; and investigate any potential unintended consequences of the programs. Data Sources: Eligible publications from MEDLINE, Current Contents Connect (Clarivate Analytics), Science Citation Index (Clarivate Analytics), Social Sciences Citation Index (Clarivate Analytics), and ProQuest Dissertations indexed through 27 December 2017 and additional studies from reference lists. Study Selection: Observational studies (published in English) from U.S. states that examined an association between PDMP implementation and nonfatal or fatal overdoses. Data Extraction: 2 investigators independently extracted data from and rated the risk of bias (ROB) of studies by using established criteria. Consensus determinations involving all investigators were used to grade strength of evidence for each intervention. Data Synthesis: Of 2661 records, 17 articles met the inclusion criteria. These articles examined PDMP implementation only (n = 8), program features only (n = 2), PDMP implementation and program features (n = 5), PDMP implementation with mandated provider review combined with pain clinic laws (n = 1), and PDMP robustness (n = 1). Evidence from 3 studies was insufficient to draw conclusions regarding an association between PDMP implementation and nonfatal overdoses. Low-strength evidence from 10 studies suggested a reduction in fatal overdoses with PDMP implementation. Program features associated with a decrease in overdose deaths included mandatory provider review, provider authorization to access PDMP data, frequency of reports, and monitoring of nonscheduled drugs. Three of 6 studies found an increase in heroin overdoses after PDMP implementation. Limitation: Few studies, high ROB, and heterogeneous analytic methods and outcome measurement. Conclusion: Evidence that PDMP implementation either increases or decreases nonfatal or fatal overdoses is largely insufficient, as is evidence regarding positive associations between specific administrative features and successful programs. Some evidence showed unintended consequences. Research is needed to identify a set of "best practices" and complementary initiatives to address these consequences. Primary Funding Source: National Institute on Drug Abuse and Bureau of Justice Assistance.

Constant Lethality of Gunshot Injuries From Firearm Assault: United States, 2003-2012.

OBJECTIVES: To investigate the validity of the apparent downward trend in the national case-fatality rate for gunshot wounds from assault. METHODS: We reanalyzed the estimated annual number of nonfatal firearm injuries the National Electronic Injury Surveillance System reported from 2003 to 2012. We adjusted the estimates for discontinuities created by the substitution of 1 hospital for another in the sample and for a downward trend in the percentage of gunshot injuries classified as "unknown circumstance." Firearm homicide data are from the Centers for Disease Control and Prevention, Web-based Injury Statistics Query and Reporting System. RESULTS: The unadjusted National Electronic Injury Surveillance System estimate increased by 49%, yielding a decline in the case-fatality rate from 25% to 18%. Our adjustments eliminated these trends; the case-fatality rate was 22% in both 2003 and 2012. CONCLUSIONS: With reasonable adjustments, the trend in nonfatal injuries from interpersonal firearms assault tracks the flat trend in firearms homicides, suggesting that there was no increase in firearms violence during this period. The case-fatality rate did not change, and trauma care improvements did not influence the firearms homicide trend.