Gomez C, Berlin I, Marquis P, Delcroix M Expired air carbon monoxide concentration in mothers and their spouses above 5 ppm is associated with decreased fetal growth. Prev Med. 2005 Jan;40(1):10-5. doi: 10.1016/j.ypmed.2004.04.049.
McClure JB Are biomarkers a useful aid in smoking cessation? A review and analysis of the literature. Behav Med. 2001 Spring;27(1):37-47. doi: 10.1080/08964280109595770.
Middleton ET, Morice AH Breath carbon monoxide as an indication of smoking habit. Chest. 2000 Mar;117(3):758-63. doi: 10.1378/chest.117.3.758.
Riaz M, Lewis S, Coleman T, Aveyard P, West R, Naughton F, Ussher M Which measures of cigarette dependence are predictors of smoking cessation during pregnancy? Analysis of data from a randomized controlled trial. Addiction. 2016 Sep;111(9):1656-65. doi: 10.1111/add.13395. Epub 2016 May 6.
Shahab L, West R, McNeill A A randomized, controlled trial of adding expired carbon monoxide feedback to brief stop smoking advice: evaluation of cognitive and behavioral effects. Health Psychol. 2011 Jan;30(1):49-57. doi: 10.1037/a0021821.
Smoking Reduction In Gravid Women With Substance Use Disorders (SIGS): A Randomized Controlled Trial
Interventional studies are often prospective and are specifically tailored to evaluate direct impacts of treatment or preventive measures on disease.
Observational studies are often retrospective and are used to assess potential causation in exposure-outcome relationships and therefore influence preventive methods.
Expanded access is a means by which manufacturers make investigational new drugs available, under certain circumstances, to treat a patient(s) with a serious disease or condition who cannot participate in a controlled clinical trial.
Clinical trials are conducted in a series of steps, called phases - each phase is designed to answer a separate research question.
Phase 1: Researchers test a new drug or treatment in a small group of people for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
Phase 2: The drug or treatment is given to a larger group of people to see if it is effective and to further evaluate its safety.
Phase 3: The drug or treatment is given to large groups of people to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.
Phase 4: Studies are done after the drug or treatment has been marketed to gather information on the drug's effect in various populations and any side effects associated with long-term use.
