Walker et al. BMC Public Health 2011, 11:37 http://www.biomedcentral.com/1471-2458/11/37 and tar content of the trial cigarettes, independent ver- ification will be undertaken by Labstat Canada. Specifi- cally, the nicotine content of the unburnt nicotine-free cigarettes will be assessed (including analysis of nico- tine alkaloids by gas chromatography and tobacco moisture), as will total particulate matter, water, nico- tine, particulate matter (water and nicotine free), car- bon monoxide and puff number. Control group: Participants allocated to the control arm of the trial will be asked to stop smoking com- pletely on their chosen Quit day and will be sup- ported by Quitline in the usual way for eight weeks, with counselling/advice and NRT in the form of a patch, gum and/or lozenge (Figure 1). Current standard cessation practice at the New Zealand Quitline (as at December 2010) is as follows (other cessa- tion providers in New Zealand do not follow the process outlined here): Quitline issues by post, a Quit Card (with a 90 day expiry) for eight weeks supply of up to three NRT products (patch, gum and/or lozenge) and makes routine support calls by telephone over eight weeks. These support calls are administered by the Quitline advisors as required. Quitting support generally involves an average of three follow-up telephone calls, each lasting about 10-15 minutes. However, if people do not wish to receive support calls, they are not scheduled but callers are advised that they can phone Quitline at any time for support. Participants are advised to take the Quit Card to a pharmacist in exchange for subsidised patches, gum and/or lozenges (NZ$3 per item per four-week course of NRT). The strength of NRT patch, gum, and/or lozenges to be used by each participant is determined by the Quit- line advisor (as per their dosage guidelines) as to the degree of each person’s nicotine dependency. “Quit day” in this study will refer to the day each participant stops smoking cigarettes containing nicotine. Baseline assessments Participants from throughout New Zealand will call Quitline seeking advice and wishing to enrol in the Quitline smoking cessation programme. A Quit advisor from Quitline will undertake the standard Quitline assessment. A list of those individuals who indicate that they wish to take part in research will be transferred from the Quitline database to the trial research assis- tants based at Quitline. The research assistants will attempt to make contact with people on the list. Those contacted will be told about the trial and asked if they would like to participate. If the potential participant indicates that they are interested, they are consented and asked for demographic data (age and sex) and checked to see if they meet the inclusion criteria for the trial. For those that do meet the inclusion criteria, Page 4 of 8 further details will be collected about the participant’s ethnicity and level of nicotine dependence (as deter- mined by the FTND Questionnaire [6]) and they will be randomised Data from this initial assessment will then be electronically transferred (securely) to the Clinical Trials Research Unit’s Oracle database. The research assistant will then collect the following baseline data from each participant over the telephone. Demographic information: Socio-economic posi- tion, based on income, education and occupation. Smoking history: Age when started, number of cigarettes smoked per day, number of years as regu- lar smoker, number of previous unsuccessful attempts to give up in past 12 months and the method used, other types of smoking (pipe, cigar), usual brand/pack size (and how long pack lasts), and type of cigarettes smoked per day (e.g. roll-your-own or factory-made). Other smoking related information: Self-rated chances of quitting (measured on a scale of one to five, where one is very low and five is very high), household smoking, smoking in cars. Concomitant medication: Information about types of medication currently used will be collected. The physical signs and symptoms associated with withdrawal: Measured using the Mood and Physical Symptoms Scale (MPSS) [7]. Additional withdrawal questions will also be asked related to the frequency of disturbed sleep, anxiety, mouth ulcers, cough, impatience, dizziness and increased dreaming [8]. Alcohol use and abuse: Measured using the Alco- hol Use Disorders Identification Test (AUDIT-C), a screening tool that helps to identify people who are hazardous drinkers or have active alcohol use disor- ders (including alcohol abuse or dependence) [9]. Outcome measures Primary outcome The proportion of participants who self-report having stopped smoking at six months after their Quit date. ‘Stopped smoking’ will be defined as having consumed no nicotine cigarettes (not a single puff) in the previous seven days (seven-day point prevalence). Secondary outcomes The following secondary outcome measures will be assessed at three and six weeks after the Quit date in the treatment group only: Information related to the use of the nicotine-free cigarettes: Participants will be asked for their views on the use of the nicotine-free cigarettes (including concerns, whether they liked the taste of them, etc),