Nancy Carnide

U of T experts on cannabis in the workplace: We need an accurate measure of impairment

noreen.rasbach — Wed, 17 Oct 2018 15:15:28 +0000

U of T experts on cannabis in the workplace: We need an accurate measure of impairment noreen.rasbach Wed, 10/17/2018 - 11:15

Cutline

Police officers in Ottawa and Vancouver face no restrictions on their off-work use of cannabis as long as they are fit for duty, officers in Calgary have been banned from use and in Toronto they face a 28-day abstinence period (photo by Shutterstock)

Topic

Research & Innovation

The Conversation

Workplace

Now that marijuana is legal in Canada for recreational purposes, one question hanging in the air is whether more Canadians will smoke weed on their way to work, or step out to purchase it during their coffee break.

If they do, how will this impact workplace productivity, and health and safety? This question is especially pertinent in occupations involving driving or operating heavy machinery, and those involving law enforcement and the provision of medical care to the public.

The federal government’s legalization of recreational marijuana raises occupational health and safety concerns for many employers – from banks to health authorities to construction companies, airlines to police departments.

Cannabis on campus: U of T ramps up efforts to educate students, staff and faculty

At the Institute for Work & Health (IWH), we have been reviewing the effects of various drugs that act on the central nervous system – including marijuana – on workplace injuries, deaths and near-misses.

What is striking is how little high-quality evidence there is on the impacts of marijuana in the workplace and how inconsistent the existing data is.

We urgently need high-quality observational research studies to be able to better understand the effects of marijuana on work. We also need to develop an accurate measure of impairment for use in Canadian workplaces.

No published studies on legalization

As far as we’re aware, no published studies to date have examined the impact of recreational marijuana legalization on the workplace.

The only data we’ve seen is from an annual report by a large private drug-testing company in the United States. It found that rates of positive cannabis tests (of urine samples) have increased most markedly in states that have enacted recreational use legislation.

But these rates are based on the number of tests conducted rather than on the number of workers. Therefore, it’s not clear whether this reflects an increase in the use of cannabis in the workplace.

In many workplaces, health and safety is a life and death matter (photo by Shutterstock)

Workplace injuries and accidents

Several studies have examined the impact of marijuana use on workplace outcomes, but with mixed results.

Some have found associations between marijuana use in the workforce and work absenteeism, reduced productivity, job turnover, disciplinary measures, workplace accidents and injuries, unemployment and interpersonal conflict.

However, other studies have found no association with some of these outcomes. Overall, the evidence to date is quite inconsistent.

In 2017, the U.S. National Academy of Sciences published a major report on the health effects of marijuana use, including impacts on injuries and accidents in a workplace setting.

Based on six studies, the review did not find enough evidence to either support or refute a statistical link between marijuana use and occupational injuries or accidents.

No indicator for acute impairment

Some of the inconsistency in the research that does exist may be due to differences in study designs and methodologies and difficulties in conducting this type of research.

Also, much of the evidence in this area comes from post-incident investigations, where the workers involved are tested for marijuana or other drugs following a workplace incident.

These kinds of cases tend to be more publicized, but rigorous research with control groups (i.e., those who did not have an accident) is needed to understand whether there are more accidents among those using marijuana compared to those who are not.

And even though workers may test positive for tetrahydrocannabinol (THC) in their urine, that doesn’t necessarily mean they were impaired at the time of the accident. Marijuana remains in the system for quite some time. So someone can use marijuana on Friday night and come into work on Monday no longer impaired, yet produce positive urine tests for marijuana use.

That said, no consensus currently exists around the length of time someone should wait between consuming cannabis and engaging in safety-sensitive work, giving rise to employer concerns about the timing of off-work consumption.

The Lower-Risk Cannabis Use guidelines for Canada suggest users wait six hours or even longer before driving or operating machinery. More recently, the Occupational and Environmental Medicine Association of Canada released a position statement on cannabis use in safety-sensitive work, recommending a wait time of at least 24 hours before engaging in safety-sensitive work.

On construction sites, the capacity of employees to fulfil their work safely is of paramount importance (photo by Shutterstock)

But the lack of clear evidence around the issue of impairment has led to the emergence of vastly different policies from employers across Canada. For instance, whereas police officers in Ottawa and Vancouver face no restrictions on their off-work use as long as they are fit for duty when they show up for work, officers in Calgary have been banned outright from using cannabis and Toronto officers face a 28-day abstinence period.

Likewise, everyone working in safety-critical areas at Air Canada and WestJet, a broad group comprising flight and cabin crew members, aircraft maintenance engineers and flight dispatchers, are prohibited from using cannabis whether on- or off-duty.

New research directions

We have some, but limited, data on the extent of workplace cannabis use in Canada (e.g. during work, on breaks and in the hours prior to a work shift). According to 2015 data from Statistics Canada’s Canadian Alcohol and Drug Use Monitoring Survey, 15.5 per cent of the working population report using cannabis in the previous 12 months. What’s more, 6.4 per cent of the working population report using cannabis once a week or more.

According to Health Canada’s 2017 Canadian Cannabis Survey, 21.5 per cent of cannabis users report using cannabis to get high before or at work in the previous year, including 7.7 per cent who report weekly or daily use before or at work.

To delve deeper into the issue, we at the Institute for Work & Health have recently conducted a survey of 2,000 Canadian workers, with funding from the Canadian Institutes of Health Research.

We measured the current magnitude of cannabis consumption at work, reasons for workplace use, perceptions of its effects on work and availability in the workplace. Analysis is under way and early results will be shared later this year. The results will importantly provide a starting point for monitoring the long-term impact of legalization on workplace health and safety issues.

With this survey, which was completed in June 2018, we now have a pre-legalization baseline upon which future population-level surveys of habits and attitudes around the use of cannabis at work can be analyzed.

We also have a cohort that can potentially take part in a longitudinal observational study. That would allow us to understand the impact of this major policy change at an individual level. The answers that come out of that research may point the way to new workplace programs and policies to influence individuals’ decisions on cannabis use at work.

An earlier Q & A version of this story was previously published in At Work.

Andrea Furlan is an associate professor of medicine at the University of Toronto and a scientist at the Institute for Work and Health. Nancy Carnide is a U of T post-doctoral researcher at the Institute for Work & Health.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Marijuana in the workplace: What is unsafe?

noreen.rasbach — Thu, 25 Jan 2018 15:49:38 +0000

Marijuana in the workplace: What is unsafe? noreen.rasbach Thu, 01/25/2018 - 10:49

Cutline

Will offices, construction sites and medical clinics be full of stoned workers after Canada’s promised marijuana legalization date of July 2018? (photo by Shutterstock)

Topic

Research & Innovation

The Conversation

Subheadline

The Conversation with U of T's Andrea Furlan and Nancy Carnide

When marijuana is legal later this year in Canada, many Canadians may consider smoking weed on their way to work, or stepping out to purchase it during their coffee break.

How will this impact workplace productivity, and health and safety – especially in occupations involving driving or operating heavy machinery?

The federal government’s commitment to legalize recreational marijuana by July 1 raises occupational health and safety concerns for many employers.

What is striking is how little high-quality evidence there is on the impacts of marijuana in the workplace and how inconsistent the existing data is.

No published studies on legalization

As far as we’re aware, no published studies to date have examined the impact of recreational marijuana legalization on the workplace.

The only data we’ve seen is from a report released in 2017 by a large private drug-testing company in the United States. It found that the rates of positive cannabis tests in Washington and Colorado in 2016 outpaced the national average for the first time since the two states legalized cannabis in 2012.

But these rates were based on the number of tests conducted, so it’s not clear whether this reflects an increase in the number of employees testing positive.

Workplace injuries and accidents

Several studies have examined the impact of marijuana use on workplace outcomes, but with mixed results.

However, other studies have found no association with some of these outcomes. Overall, the evidence to date is quite inconsistent.

In 2017, the U.S. National Academy of Sciences published a major report on the health effects of marijuana use, including impacts on injuries and accidents in a workplace setting.

Based on six studies, the review did not find enough evidence to either support or refute a statistical link between marijuana use and occupational injuries or accidents.

No indicator for acute impairment

Some of the inconsistency in the research that does exist may be due to differences in study design and methodologies and difficulties in conducting this type of research.

Also, much of the evidence in this area comes from post-accident investigations, where the workers involved are tested for marijuana or other drugs following a workplace incident.

There is no consensus as of yet on the levels of THC detected in fluids that indicate acute impairment.

Slower driving reaction times

Often, the findings of studies measuring the impact of marijuana on driving are extrapolated to work settings, to understand the potential hazards of marijuana on workplace safety. But even in the area of driving research, there is much still to be understood.

Researchers know marijuana use impairs driving, but it’s not yet clear how it does so. What is consistent among the studies published is that reaction time is slower, so people also drive slower.

Also, it isn’t clear to what extent you can extrapolate driving-to-work situations. Driving is a learned activity that many people do almost on auto pilot. Drivers’ brains are often multi-tasking; many people are talking or doing a secondary task while behind the wheel.

That kind of activity may be similar to some work situations, but not to others.

New research directions

We have very limited data on the extent of workplace cannabis use (for example, during work, on breaks and in the hours prior to beginning a work shift) and impairment among workers in both the U.S. and Canada.

To address this gap, we have recently received funding from the Canadian Institutes of Health Research, along with Dr. Peter Smith, to conduct a survey of Canadian workers.

We will measure the current magnitude of cannabis consumption at work, reasons for workplace use, perceptions of its effects on work and availability in the workplace.

It will also be important to study the potential health impacts on workers involved in the production of cannabis. Some researchers in Washington State are beginning to look at this, with an initial focus on the effects of UV radiation.

Finally, one of the key avenues for future research will be to identify an accurate measure of impairment for use in workplaces. This is something that the workplace community is particularly keen to see.

Andrea Furlan is an associate professor in U of T's Faculty of Medicine. Nancy Carnide is a post-doctoral fellow at the Institute for Work & Health.

An earlier Q & A version of this story was previously published in At Work. This article was originally published on The Conversation. Read the original article.