Dean's COVID-19 Commentary

The quick Colorado COVID-19 summary: finally, a clear downward trend with last week’s hospitalization count at 143; cases are trending down in parallel; and wastewater concentrations are heading lower in most jurisdictions. The national trend is similarly downward. 

Until Wednesday, April 19, I was unaware of the special significance of April 20, particularly in Colorado. My education on the topic was prompted by the school's release of a massive scoping review on high-potency marijuana and THC concentrates on April 19. The Colorado School of Public Health was charged with carrying out the review under House Bill HB 1317, passed in the 2021 session of the Colorado General Assembly. The bill called on the school to carry out a systematic review “…related to the physical and mental health effects of high-potency [Note added: Delta-9 Tetrahydrocannabinol (THC)] THC marijuana and concentrates.” Additionally, HB 1317 required that ColoradoSPH “…shall produce a public education campaign for the general public regarding the effect of high-potency marijuana on the developing brain and on physical and mental health.”  

Drawing on the faculty, staff, and students at the Colorado School of Public Health and CU School of Medicine, we put together the team needed to complete this type of review: topic experts; review methodologists; and a support team that included an army of students to comb through the 66,000 publications identified initially. At the end of the scoping review process, we had extracted data from 452 articles found to meet inclusion criteria, created an evidence map, and implemented a dashboard so that the articles could be readily accessed and filtered for their contents. The report submitted to the legislature on April 19 and the dashboard can be accessed on our “Cannabis Research & Policy Project” website. 

We were looking for evidence that would support potential interventions to protect public health, such as regulating the concentration of THC in various cannabis products, and that would become the basis for the public education campaign. As documented in the report, the utility of scientific literature for these purposes is diminished by the poor quality and limited relevance of many of the studies. Only some studies—those carried out more recently—are relevant to today’s marketplace of higher concentration products. Additionally, too many studies are affected by the usual litany of methodological flaws. One of the most challenging aspects of epidemiological studies on cannabis is assessing product use, given the wide range of options (e.g., flower, edibles, and vape pens), and the dynamic nature of products.  

We did not find strong evidence to answer key policy questions, perhaps most importantly whether a threshold THC concentration could be specified that would protect against adverse consequences of using cannabis products. For most of the health areas examined, such as worsening mental health for those with an underlying mental health problem, the number of studies was limited, and study quality was a problem. Given the growing number of states with legal recreational and medical cannabis, there is an urgent need for better evidence so that we can understand the public health consequences of legalization. Barriers to research need to be addressed including inadequate funding and insufficiently developed research methods, such as a lack of standardized approaches for characterizing use.  

Some suggested that we should wait a day and release the report on April 20 or 4/20. For those of you as cannabis-naïve as I, here is background on 420, referring to cannabis and cannabis celebrations. There were numerous events in Colorado, including, for example, the Mile High 420 Festival. We stuck with 4/19. 

Motivated by a spate of recent publications and reviews, I recently finished two books that fit into the genre of “climate fiction” or “cli-fi.” With climate models predicting a hotter and weather-riskier planet, why read fiction about how bad the world might be? I asked myself this question after finishing Neal Stephenson’s 720-page Termination Shock and then Bruce Holsinger’s 448-page The Displacements. The former might be summarized as climate engineering may have bad outcomes, and the latter as ever more extreme weather events will disrupt lives. Both deliver their messages through engaging plot lines. Stephenson’s book interweaves three plot lines that eventually converge, although that point is not obvious at the book’s start—a plane flown by the Queen of the Netherlands crashing into an outsized mutant feral pig on a runway in Texas. Holsinger’s book begins with the destruction of Miami by the first Category 6 hurricane and then moves to happenings at the FEMA encampment where the displaced end up. There are many other books in this genre, reflecting the pervasive worries of many of us concerning the impact of climate change. On the shelf: Kim Stanley Robinson’s The Ministry for the Future (576 pages).

Stay well.

Jonathan Samet, MD, MS
Dean, Colorado School of Public Health