This study tests the effects of cannabinoid levels in blood on inflammation and insulin sensitivity both acutely and chronically in individuals across the weight spectrum. To that end, the study employs two observational designs: 1) A study of acute effects with intermittent cannabis users and 2) A study in which current cannabis users will select one of three cannabis strains for four weeks and are compared to a matched control group who do not use cannabis to study chronic effects. Blood levels of THC and CBD, inflammatory biomarkers, and insulin resistance will be measured in both studies.
According to the National Institute of Diabetes and Digestive and Kidney Diseases, over 30 million people in the US have diabetes, and just over 84 million people have pre-diabetes. Concurrently, 30 states and the District of Columbia have legalized cannabis for medical and/or recreational use and over the past decade, cannabis use among adults has more than doubled. Public perception and some scientific data suggest that cannabis causes acute over-eating, creating concern that public and legal acceptance of cannabis use will worsen the obesity epidemic in the United States, where more than two-thirds of US adults (68.8%) are currently overweight or obese. Paradoxically, cross sectional data demonstrate associations between chronic cannabis use and lower body mass index (BMI), prevalence of obesity, insulin resistance, waist circumference, and actual rates of type 2 diabetes despite data supporting higher caloric intake acutely. This study examines the effects of cannabinoid levels in blood on inflammation and insulin sensitivity both acutely and chronically in individuals across the weight spectrum. To that end, the study employs two observational designs: 1) A study of acute effects with intermittent cannabis users and 2) A study in which current cannabis users will select one of three cannabis strains for four weeks and are compared to a matched control group who do not use cannabis to study chronic effects.
Study Type
OBSERVATIONAL
Enrollment
233
Participants are asked to purchase and use one of three cannabis flower strains with differing levels of THC and CBD: 1) CBD (\~14% CBD/0% THC), 2) THC (\~14% THC/0% CBD), or 3) THC+CBD (\~7% THC/7% CBD).
Participants choose whether to use a cannabis flower product ad libitum for four weeks or to not use cannabis for four weeks. Participants who choose to use cannabis are asked to purchase and use one of three cannabis flower strains with differing levels of THC and CBD: 1) CBD (\~14% CBD/0% THC), 2) THC (\~14% THC/0% CBD), or 3) THC+CBD (\~7% THC/7% CBD).
Center for Innovation and Creativity
Boulder, Colorado, United States
Markers of Inflammation
Change in Circulating Levels of Cytokines (TNF-α, IL-6, IL-1β, IL-12, IFNG, and IL-4). Results are reported as a composite score of TNF-α, IL-6, IL-1β, IL-12, IFNG, and IL-4
Time frame: Study A: Difference between cytokines at baseline and cytokines one week later after acute use of cannabis product. Study B: Change from baseline to four weeks
Change in Matsuda Index of Insulin Sensitivity
Calculation of Insulin Sensitivity using changes in fasting plasma glucose (FPG) and fasting plasma insulin (FPI). Measurements are collected on venous blood samples at 0, 30, 60, 90, and 120 minutes after ingestion of 75 grams oral glucose during oral glucose tolerance test (OGTT). Values across the timepoints were combined to create a Matsuda Index score as follows: 10000/sqrt ((FPG X FPI) X (Mean OGTT glucose concentration X Mean OGTT insulin concentration)). Higher scores mean higher sensitive to insulin and that your body more efficiently clears glucose from your bloodstream, thus higher scores are better.
Time frame: Study A: Baseline versus after acute use one week later of cannabis product. Study B: The two tests will be separated by four weeks
Change in Plasma Glucose
Change in glucose over time after ingestion of 75 grams oral glucose measured during during oral glucose tolerance test (OGTT). Measurements are collected on venous blood samples at 0, 30, 60, 90, and 120 minutes and averaged across these timepoints for a mean score.
Time frame: Study A: Baseline versus one week later after acute use of cannabis product. Study B: The two tests will be separated by four weeks
Change in Plasma Insulin
Change in insulin over time after ingestion of 75 grams oral glucose measured during OGTT. Measurements are collected on venous blood samples at 0, 30, 60, 90, and 120 minutes and averaged across these timepoints for a mean score.
Time frame: Study A: Baseline versus one week later after acute use of cannabis product. Study B: Baseline versus four weeks later
Stanford Seven-Day Physical Activity Recall (PAR)
Interviewer administered assessment of number of minutes of moderate to vigorous physical activity over the previous seven days. Scores are reported as total minutes in the last week summed across moderate, hard, and very hard activity levels.
Time frame: Study A: Baseline and one week following baseline Study B: Baseline and four weeks following baseline
Sleep Quality
Pittsburgh Sleep Quality Index: Measurement of the quality and patterns of sleep from poor to good measuring seven domains (e.g., latency, duration, disturbances) over the last 2 weeks. Participants' scores are reported as a global score of the summed seven component scores together ranging from 0 to 21, where higher scores indicate worse sleep and a global score of 5 or above indicates poor sleep quality.
Time frame: Study A: Baseline only Study B: Baseline to four weeks following baseline
Marijuana Consumption Questionnaire
Times per day of cannabis flower use from 0 to 6. Includes all participants in Study A and only cannabis users in Study B.
Time frame: Study A: Baseline only. Study B: Baseline and four weeks following baseline
Marijuana Dependence Scale
This is a self-report scale based on DSM-5 criteria to assess dependence and other problems related to the use of cannabis. Scores are reported as a sum across the 11 items with yes/no options, ranging from 0 to 11, with higher scores indicating more dependence symptoms. Includes all participants in Study A and only cannabis users in Study B.
Time frame: Study A: Baseline only. Study B: Baseline and four weeks following baseline
Marijuana Withdrawal Checklist
A 15-item scale used to collect information on withdrawal symptoms that participants may be experiencing due to the lack of use of marijuana. Options range from 0 (none) to 3 (severe) for each question and are summed to create a final score ranging from 0 to 45. Includes all participants in Study A and only cannabis users in Study B.
Time frame: Study A: Assessed at follow-up, one week following baseline. Study B: Assessed at follow-up, four weeks following baseline.
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The Alcohol Use Disorder Identification Test (AUDIT)
Standardized assessment of the extent of alcohol use and problems related to alcohol use. Scores are summed and range from 0 to 40 with higher scores indicating more hazardous alcohol use.
Time frame: Study A: Baseline only. Study B: Baseline and four weeks following baseline
Timeline Follow-Back of Substance Use
Calendar-based assessment of daily substance use for the 30 days prior to the baseline session for both studies. The average days of smoked cannabis use in the last 30 days are reported.
Time frame: Study A: Baseline only. Study B: Baseline and four weeks following baseline
SF-12 Health Survey
The SF-12 Health Survey is a 12-item questionnaire used to assess general health and well-being and includes domains of physical functioning, role-physical, pain, general health, vitality, social functioning, role-emotional and mental health. Only the mental component was analyzed. Scores are calculated using a weighted algorithm with scores ranging from 0 to 100; scores greater than 50 meaning better than average health and scores worse than 50 meaning worse than average health.
Time frame: Study A: Baseline only. Study B: Baseline and four weeks following baseline
Nutrition Data System for Research 24-Hour Dietary Recall
Interviewer administered recall measure developed by the University of Minnesota Nutrition Coordinating Center (NCC), that facilitates the standardized collection of 24-hour dietary recall data. Healthy Eating Index (HEI) total scores are reported for each participant, which is a measure of healthy eating on a scale of 0 (poor eating) to 100 (very healthy eating). Scores above 80 indicate a good diet, and scores below 80 indicate a diet in need of improvement.
Time frame: Study A: Baseline and one week following baseline Study B: Baseline and four weeks following baseline
Stanford Leisure-Time Activity Categorical Item (L-Cat)
Self-report measure of a single item comprising six descriptive categories ranging from inactive (1) to very active (6).
Time frame: Study A: Baseline and one week following baseline Study B: Baseline and four weeks following baseline