Please select the eligibility criteria that correspond to the clinical trial below.
Title: Vascular Effects of Regular Cigarettes Versus electronIc Cigarette Use
Brief Summary: The purpose of this study is to assess the effects of electronic cigarettes-nicotine and electronic cigarette-nicotine free on endothelial function as compared to traditional cigarettes. Due to ethical reasons, we cannot fully randomise all particpants to the three arms.

Participants who wish to quit smoking will be randomized to

1. Switch to electronic cigarettes containing nicotine plus flavor
2. Switch to electronic cigarettes containing flavor alone Those who do not wish to quit smoking will continue on the Tobacco Cigarette arm Treatment period will be 28 days


Options:
A: Inclusion Criteria:

1. self-identify as African American or Black;
2. age 18 years or older;
3. smoke at least five cigarettes daily for the past year;
4. not interested in quitting smoking in the next 6 months;
5. Willing to use e-cigarettes;
6. Good physical health (no unstable medical or mental health condition);
7. no contraindications for e-cigarette use.

Exclusion Criteria:

1. Recent unstable or untreated psychiatric diagnosis including substance abuse, as determined by the DSM-IV criteria;
2. use in the past 30 days of tobacco or nicotine products including e-cigarettes, other than regular cigarettes;
3. participation in a smoking cessation program in the past 30 days;
4. pregnant or nursing.
B: Inclusion Criteria:

* Schizophrenic subjects (according to DSM-IV-TR criteria) from throughout Sicily, (Italy), who smoke tobacco cigarettes, in stable phase of illness.
* smoke ≥10 factory made cig/day, for at least the past five years
* age 18-65 years
* in good general health
* not currently attempting to quit smoking or wishing to do so in the next 30 days (a specific test will be included to check their unwillingness to quit) 6 months
* committed to follow the trial procedures.

Exclusion Criteria:

* use of smokeless tobacco or nicotine replacement therapy
* pregnancy or breastfeeding.
* current or recent (less than 1 yr) past history of alcohol and/or drug abuse
* other significant co-morbidities according to the Investigator's clinical assessment
C: Inclusion Criteria:

* Study I - First Phase - No Longer Recruiting

  * Greater than 1 year history of daily smoking
  * 1 month or more of e-cigarette use
  * Able to speak and read English
  * (1) current dual users (of tobacco cigarettes and e-cigarettes) without interest in quitting smoking; (2) current dual users who have attempted, but not quit smoking; (3) current e-cigarette users who have successfully quit smoking; and (4) former dual users who have quit both products.
* Study I - Second Phase - No Longer Recruiting

  * Current dual users (of tobacco cigarettes and e-cigarettes)
  * Smoking at least one cigarette per day over the past year
  * Using e-cigarettes at least once per week over the past month
  * Not currently enrolled in a face-to-face smoking cessation program
  * Able to speak and read English
* Study II - No Longer Recruiting

  * Current dual users (of tobacco cigarettes and e-cigarettes)
  * Smoking at least one cigarette per week over the past year
  * Using e-cigarettes at least once per week over the past month
  * Not currently enrolled in a face-to-face smoking cessation program
  * Able to speak and read English
D: Inclusion Criteria:

* Aged 18 years and over
* Currently smoking ≥15 full strength tobacco cigarettes per day for at least 2 years, or roll-up tobacco equivalent (cigar or pipe smokers not included).
* Willing to stop tobacco cigarettes for period of study if required
* Willing not to use electronic cigarettes if required
* Able to give informed consent

Exclusion Criteria:

* Pregnant or lactating.
* Women of childbearing potential who do not abstain from sex or use effective contraception.
* On current prescribed medication for cardiovascular disease.
* History of cardiovascular disease (excluding hypertension), diabetes, active malignance or chronic renal disease.
* Nut allergy
* Participation in another clinical trial (other than observational trials and registries) with an investigational product and/or intervention within 30 days before visit 1.

Answer: D