Medical Cannabis Use In Canada: Vapourization And Modes Of Delivery

An online cross-sectional survey was conducted from April 29 until June 8, 2015. No public sampling frame was available from which to sample approved medical cannabis users nor was there any reliable way of verifying approved status without disclosure of sensitive health care records. Therefore, the current study recruited approved users through licensed producers-the only legal source of medical cannabis in Canada. At the time of the survey, a total of 16 licensed producers who were registering clients in Canada were identified and approached to assist with study recruitment. Nine licensed producers agreed and sent their registered customers an email invitation with information about how to contact the study investigators. Eligible respondents were approved medical cannabis users, 18 years of age or older, and reported cannabis use in the past 30 days for health reasons. Eligible respondents were provided with a unique password via email to access the survey. Respondents who completed the survey received $10 as a thank you for completing the survey, provided via an electronic gift card or interact email payment. In order to protect confidentiality and to minimize social desirability bias, email addresses were the only personally identifying information collected from respondents. The study received approval from the Office of Research Ethics at the University of Waterloo.

Survey measures

Survey measures were drawn from previous sources and adapted for the current study [4, 6, 7, 13, 24]. New and adapted measures underwent cognitive interviewing with approved medical cannabis users [25].

Sociodemographics

Ethnicity was classified as White or Non-white (including South Asian, Chinese, Black, Filipino, Latin American, Arab, Southeast Asian, West Asian, Korean, Japanese, Aboriginal, or multi-racial). Education levels included Low (completion of high school or less), Moderate (technical/trade school, community college, or some university, but no degree), and High (university degree or more). Respondents were classified into five regions of Canada: Atlantic (New Brunswick, Newfoundland and Labrador, Nova Scotia, and Prince Edward Island), Prairies (Alberta, Manitoba, and Saskatchewan), Ontario and Northern (Ontario, Northwest Territories, and Nunavut) Quebec, and British Columbia. Personal income levels included Low ($0 to $40,000), Middle ($40,001 to $80,000), and High (more than $80,001). Cigarette smoking status was classified as not at all, occasionally, or daily.

Medical cannabis use

The amount of cannabis used was examined by asking respondents to report on average how many grams of marijuana they use per day, per week, or per month. Respondents reported their frequency of cannabis use in the past 3 months as every day, almost every day, or less than almost every day, as well as number of uses per day. The main medical reason for cannabis use included five categories: Pain relief (chronic pain and fibromyalgia), Mental health (anxiety or nerves, depression, ADHD, bipolar, PTSD), Central nervous system (multiple sclerosis, spinal cord injury, and epilepsy), Side effects (nausea or vomiting and lack of appetite or weight loss), and Other in which a text box was provided for further explanations (other, glaucoma, cancer, insomnia).

Self-reported respiratory symptoms were examined using six previously adapted questions [13]. An index was used to represent the number of respiratory symptoms reported (0-6). Perceived harm from smoking cannabis was assessed as Low (not at all harmful to my health), Moderate (a little or somewhat harmful), and High (very or extremely harmful).

Prevalence of modes of delivery

Respondents were asked to report Ever, Current (i.e. past 30 day use), and Preferred modes of delivery by selecting from a list, as follows: smoking a joint, smoking a blunt, smoking a pipe, smoking a bong or waterpipe, using a vapourizer, eating in foods or baked goods (e.g. cookies, candy), drinking (e.g. tea), taking a pill (e.g. Marinol®/dronabinol or Cesamet®/nabilone), using a spray (e.g. Sativex/nabiximols), and other. Respondents who currently used multiple modes of delivery were also asked to report the percentage of use for each mode of delivery they currently used. The use of alternative modes of delivery refers to all non-smoking modes of delivery (i.e. using a vapourizer, eating, drinking, taking a pill, using a spray, or other).

Vapourizer use

Vapourizer awareness was ascertained by asking respondents whether they had ever heard of “vapourizing or vaping marijuana” before the study. Acceptability, harm of vapourizers, and patterns of use (i.e. form, frequency, and type), as well as reasons and barriers for using a vapourizer, were assessed.

Perceptions and personal importance of dimensions by mode of delivery

Perceptions of modes of delivery were examined by asking respondents to rate 12 dimensions on a scale from 1 to 5 for the modes of delivery “smoking”, “using a vapourizer”, and “eating in foods”, separately (see Table 3 for the list of dimensions). Respondents were asked to rate the importance of reasons for selecting modes of delivery on a scale from 1 to 5 by answering, “How important are each of the factors to you in your choice of how to use marijuana”.

Analysis

All analyses were conducted using SPSS, Version 22 (IBM, Illinois). Descriptive statistics (means, standard deviation, and proportions) are reported for all primary outcomes and covariates. Two logistic regression models examined correlates for the outcomes Current modes of delivery (0 = smoked only, 1 = alternative) and Current use of vapourizers (0 = non-current use of a vapourizer, 1 = current use of a vapourizer). A linear regression model also examined correlates for the outcome respiratory symptoms (ranged from 0 = no respiratory symptoms to 6 = severe respiratory symptoms). The following set of covariates were entered into all models: age, gender, ethnicity, education, income, main medical reason, and perception of harm of smoking, with the addition of respiratory symptoms and cigarette smoking status included as covariates in the Current modes of delivery model and respiratory symptoms in the Current use of vapourizer model. Adjusted odds ratios (AOR) and 95 % confidence intervals (95 % CI) are reported. In addition, an ANOVA was used to examine differences in perceptions of three modes of delivery.