There is widespread belief that, unlike tobacco smoke, cannabis smoke is benign. While the psychoactive substance in cannabis is tetrahydrocannabinol (THC) rather than nicotine, cannabis smoke is still the result of burning plant material and contains many of the same thousands of chemicals as tobacco smoke, including fine particles that cause cardiovascular disease and death. However, due to the prior illegality of cannabis, it has been difficult to study the harmful effects of cannabis smoke, and the few secondhand smoke (SHS) studies have focused primarily on whether people exposed to SHS risk testing positive on drug tests. The increasing number of states legalizing medicinal and recreational cannabis make it important to understand the public health consequences of both active and secondhand exposure to cannabis smoke.

We are recruiting healthy volunteers age 18-50 who:

• Use all forms of cannabis or tobacco products OR
• Are exposed to secondhand smoke or vape aerosol OR
• Do not use tobacco or cannabis (non-user)

Please fill out this Qualtrics survey so that we may see if you meet the study's basic requirements. If these needs are met, we will then have a phone call (~10 minutes) to go over more detailed questions as we formally conduct the recruitment process over the phone to see if you qualify. If you qualify, we will invite you to the clinic for the study procedures. 

Survey

About 240 people will take part in this study.

Study location: The ultrasound procedure, urine and blood sample collection will be done at: Cardiovascular Clinic at Mission Bay: 535 Mission Bay Blvd South, San Francisco, CA.

We plan to study the effects of cannabis and tobacco use and secondhand smoke exposure on vascular function.

Screening Procedures:

•  A phone interview will be conducted to assess your eligibility for this study.
• You will be asked to refrain from smoking tobacco, smoking cannabis, using edibles, alcohol use, and caffeine at least 12 hours before the study visit.
• You will be asked to fast for at least 12 hours before the study visit, water and medications allowed.
• If you are a female with regular periods, you will be asked to come within 7 days after the first day of your period.

Study Procedures:

• Substance use history: You will be asked to participate in an intake survey regarding your prior and current substance use including drug and alcohol abuse, diagnosis, or treatment. This will include frequency of use and number of use per week, day or month. We will also ask about your exposure to secondhand smoke and aerosol. This information will be used to assess eligibility for participation in the study and identify which study group you will be assigned to.
• Demographics: You will be asked about your gender, ethnicity, and race.
• Vital signs: We will measure your weight, height, blood pressure, pulse, and temperature to verify eligibility.
• Blood drawing: A one-time blood sample will be taken. Each sample will be approximately two tablespoons.
• Saliva collection: One-time saliva sample collection. You will be asked to collect your saliva with an oral swab. We will also ask to spit into a cup to collect additional saliva. These saliva samples will be used to measure cotinine and nicotine levels.
• Oral Buccal swab: You will be asked to or a team member will swab the inside of your cheeks with a buccal swab. This sample will be used to measure cotinine and nicotine levels. This will be used to measure inflammatory biomarkers.
• NicConfirm Test: A study member will perform a rapid measurement of cotinine and nicotine levels from your saliva or urine sample to confirm eligibility.
• Urine test: One-time urine sample collection. You will be asked to collect about a cup of your urine in the clinic to test for illicit drugs.
• Pregnancy test: If you are female and of childbearing potential, a urine pregnancy test will be done to confirm that you are not pregnant.
• Blood pressure measurements: You will lay down on a cot. Then a cuff will be placed on your arm and your blood pressure will be measured by one of the members of our team.
• Electrocardiogram (ECG): A machine measures and records the electrical activity of the heart by putting small sticky patches on certain areas of your body while you are lying down. These patches have small wires that connect to a machine which will read and print a report. The test takes about 10 minutes. No electricity is given to the body.
• Arm ultrasound: You will lay down on a cot for at least 10 minutes before staring the procedure. Then a cuff will be placed on your forearm, we will apply gel to make the images more clear. We will take ultrasound images from your arm vessels. After that, the cuff will be inflated to 250 mmHg of pressure to cut off the blood circulation for five minutes. Immediately after releasing the pressure from the cuff, ultrasound images will be obtained to measure the degree of dilation (size) in the arteries.
• Assessments of vascular stiffness: Pulse wave velocity is measured using a carotid tonometer (tool used to measure pressure of the neck vein) simultaneously with a leg cuff to capture blood pressure waveforms at the carotid (neck) and femoral (thigh) sites.
• At Home Blood Pressure: You will be given a blood pressure cuff during the study visit to take home with you and asked to obtain blood pressure readings at least five times over 24 hours. Once these are collected (either manually or through a mobile app) you will email them to us at [email protected]. You will be able to keep the blood pressure cuff as an extra gift. 

This study will be done in a one-day visit and completion of all of the procedures will take a total of 120 minutes.

Yes. You can decide to stop at any time. Tell the study doctor if you are thinking about stopping or decide to stop. He or she will tell you how to stop your participation safely. The study researcher may stop you from taking part in this study at any time if she believes it is in your best interest, if you do not follow the study rules, or if the study is stopped.

There will be no direct benefit to you from participating in this study However, the information obtained regarding the effects of chronic cannabis use on vascular function enable us to predict whether this group of people have more risk of suffering cardiovascular events in future.

Your other choices may include:

• Not participating in this study.
• Taking part in another study.

Risks and side effects related to the participation of this study include those which are:

• Ultrasound Procedure Risk: Because we will occlude the brachial artery for 5 minutes, there is a risk of minor pain or discomfort in area of cuff or proximal/distal to the cuff. Also, gel will be applied during this test which may cause coldness and /or irritation.
• Blood drawing risks: Drawing blood may cause temporary discomfort from the needle stick, bruising, infection, and fainting.
• Electrocardiogram (ECG) Risks: An ECG traces the electrical activity of the heart. You may have mild irritation, slight redness, or itching at the sites on your skin where the recording patches are placed. ECG may be skipped to prevent participant discomfort with investigator approval.
• Interview Risks: Some people feel uncomfortable when answering questions about their substance use.

No.

Yes. In return for your time, parking and travel expenses, you will be paid $100 for taking part in this study.

Researchers will use your specimens and information to conduct this study. Once the study is done using your specimens and information, we may share them with other researchers so they can use them for other studies in the future. We will not share your name or any other personal information that would let the researchers know who you are. We will not ask you for additional permission to share this de-identified information.

Participation in research involves some loss of privacy. We will do our best to make sure that information about you is kept confidential, but we cannot guarantee total privacy. Study tests that are performed by research labs, and information gathered directly from you by the researchers will be part of your research records but will not be added to your medical record. During the blood draw study team will collect a complete blood count panel and send to the lab for analysis the results from this test will show up on your medical record/MyChart. Your personal information may be given out if required by law. If information from this study is published or presented at scientific meetings, your name and other personal information will not be used.

Authorized representatives from the following organizations may review your research data for the purpose of monitoring or managing the conduct of this study:

• Representatives of the University of California
• Representatives of the sponsor (NIH)

Taking part in this study is your choice. You may choose either to take part or not to take part in the study. If you decide to take part in this study, you may leave the study at any time. No matter what decision you make, there will be no penalty to you and you will not lose any of your regular benefits. Leaving the study will not affect your medical care. You can still get your medical care from our institution. We will tell you about new information or changes in the study that may affect your health or your willingness to continue in the study. In the case of injury resulting from

You can talk to your study lead researcher about any questions, concerns, or complaints you have about this study. Contact your study lead investigator: Dr. Leila Mohammadi at [email protected].