Effect of incorporating a 10 minute point of care test for salivary ni
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《英国医生杂志》
1 General Practice, 6 Harcourt House, London W1G 0PN, 2 Wolfson Applied Technology Laboratory, Queen Elizabeth Medical Centre, Edgbaston, Birmingham B15 2TH, 3 Periodontal Research Group, University of Birmingham, St Chad's Queensway, Birmingham B4 6NN
Correspondence to: I L Chapple I.L.C.Chapple@bham.ac.uk
Objective To investigate the effect of immediate feedback from a point of care test for salivary nicotine metabolites in promoting smoking cessation and reduction in tobacco use.
Design Prospective, operator blinded, randomised controlled trial.
Setting General dental practice, London.
Participants 100 adult smokers.
Interventions Participants completed a questionnaire on smoking, undertook a clinical examination, and received counselling in smoking cessation. Saliva samples were analysed at presentation and at eight weeks for salivary nicotine metabolites using a 10 minute semiquantitative point of care test.
Main outcome measures Smoking cessation measured by salivary nicotine metabolite values (scale 0-6), patient feedback on the perceived value of the test (visual analogue scale) in quitting, and reduction in tobacco use.
Results A higher smoking quit rate was achieved with the point of care test (23% cases v 7% controls; P < 0.039), and overall tobacco use also decreased (68% cases v 28% controls; P < 0.001). Baseline values for salivary nicotine metabolites did not differ between the groups (cases, mean 4.1, SD 1.3 and 4.3, 1.4; P = 0.51). 87 participants reattended at eight weeks (44 cases, 43 controls). Mean nicotine metabolite values at eight weeks were 2.58 (2.0) for cases and 4.29 (1.8) for controls (P < 0.001).
Conclusion Incorporation of individualised personal feedback using a point of care test for salivary nicotine metabolites into a general practice based smoking cessation programme increased quit rates by 17% at eight weeks and reduced tobacco use.
The World Health Organization estimates that tobacco kills around 4.9 million people a year, and that this will rise to 10 million by 2030.1 Latest statistics indicate a 30% prevalence of smoking in UK adults, contributing to over 120 000 deaths a year and costing the health service ￡1.7bn ($3.0bn; 2.5bn).2 Of great concern is the lack of success in targeting smoking cessation among young people; by the age of 15, 28% of males and 33% of females in England smoke.3
Smoking predisposes and contributes to cytopathic changes throughout the body. Smokers have a greater incidence of coronary heart disease, myocardial infarction, peripheral vascular disease, and reduced healing rates. People with diabetes and women who use oral contraceptives are at higher risk of circulatory problems, and respiratory disease is higher among smokers. Smoking increases the risk and severity of oral cancer, periodontal disease, and premalignancy in the oral cavity.
Among healthcare professionals, dental surgeons are often in contact with the population and are in an ideal position to provide counselling and advice on smoking cessation. Even basic measures aimed at smokers who are contemplating quitting have an important effect,4 and further improvements in quit rates are reported when nicotine patches are used.5 In one study, quit rates at six and 12 weeks predicted the quit rates at 52 weeks, but only half of the participants who had quit at 6-12 weeks remained tobacco-free at one year. Another study reported 6% quit rates with the provision of intensive support and nicotine replacement therapy and concluded that if all UK general practitioners routinely offered these, up to 190 000 people could quit each year.6
Brief advice in a dental practice setting led to quit rates of 4.8-7.7%, whereas lengthier counselling, advice on nicotine replacement therapy, and the prospect of a follow-up appointment increased abstinence rates to 9.6-16.9%.7-9 A study published in the early 1990s reported that dental practitioners were less prepared than their medical colleagues to provide advice on smoking cessation,10 but recent data have shown major improvements in dental practitioners' attitudes to counselling for smoking cessation.11
Biofeedback of patient specific information on exposure to tobacco, and in particular nicotine levels, provides personalised evidence of smoke derived toxins and seems to improve patients' willingness to quit.12 Laboratory based analytical tests to evaluate smoking habit are available13 but introduce a delay in the delivery of information, particularly to the patient. Immediate access to results through point of care testing provides rapid biofeedback and facilitates the provision of treatment and patient education at the same visit. Monitoring the amount of carbon monoxide in expired air using handheld monitors discriminates between smokers and non-smokers. The short half life of carboxyhaemoglobin (2-4 hours) and its lack of specificity for tobacco, however, reduce its diagnostic accuracy.13
We have reported on a 10 minute, semiquantitative colorimetric point of care test for salivary nicotine metabolites, including cotinine, with sensitivity and specificity of 89.3% and 93.6%, respectively.14 This type of biochemical testing can also be used to overcome the physiological complexities of the inhalation, absorption, and distribution of tobacco derived chemicals throughout the body, which give each smoker a unique method of absorbing the contents of a cigarette. The saliva test (Surescreen Diagnostics; Derby, ￡3 per test) effectively condenses such variables and avoids reliance on self report by providing a single value for immediate use at the consultation visit, for future reference, and for counselling in smoking cessation.
We assessed the effect of providing smokers with visual and personalised feedback in a primary care setting on their salivary nicotine metabolite values and on quitting, and we assessed their opinions on the utility of a point of care test in helping them to quit smoking.
Participants and methods
Our study was an operator blinded, randomised controlled trial of two interventions in a sample of 100 sequentially recruited smokers within a general dental practice. We determined that with 50 participants in each group our study would have an 80% power to detect differences in quit rates of 20% or more between the two groups. KDB randomly assigned the first 100 volunteers who were current daily cigarette smokers, as reported in a self completed questionnaire, but with no specific desire to quit smoking (not a prerequisite for the study). Participants were allocated to either the case group (n = 50) or the control group (n = 50). Allocation was determined by selecting sequential numbers from two hats (one containing the participant's number (1-100) and one for group allocation) and creating a randomisation list. Participants were offered baseline assessments (enrolment), and efforts were made to ensure that members of medical staff were blinded to the participant's allocated group. We obtained written, informed consent from the participants before their inclusion in the study.
Protocol
After randomisation the participants were recalled for their baseline visit (enrolment). The study dentist (KDB) was informed of the participants' study number but remained blind to their booking details and randomisation. The practice manager allocated participants according to the randomisation schedule. The participants were given verbal counselling on smoking cessation, information about the effects of smoking on oral health (including photographs of smoking related disease), and literature packs. They were provided with a plastic container and asked to provide 2 ml of saliva by expectoration.
At this point the dentist was informed of the participants' allocated groups. Before discharge the controls were informed that they would be given their result at the next visit. The cases were shown the test procedure and given an interpretation of their salivary nicotine metabolite result before discharge. Data were entered into coded case record folders for all participants by a third member of staff, who was blind to the code allocation. The participants were recalled after eight weeks for repeat testing. They were asked if they had used, or were using, nicotine replacement therapy, as this can give a positive result on the point of care test. The operator asked participants to provide a saliva sample, which was then tested by the nurse. A third member of staff entered the results into the case record folders and a spreadsheet (Excel 97) before breaking the code and analysis.
Assay and main outcome measures
The participants were asked to refrain from consuming food or drink for 20 minutes before expectorating at least 2 ml whole, stimulated saliva into a plastic container. The saliva was analysed using a previously reported salivary nicotine metabolite assay, which utilises a colorimetric chemical reaction and direct visual comparison using a chart containing six colours, indicating varying concentrations (0-2.5 μg/ml), expressed as cotinine equivalent concentration.14 The equipment is simple and consistent with that normally present in dental and medical surgeries.
To evaluate the perceived value of the test, all cases who reattended at eight weeks completed a questionnaire to assess their opinion of the point of care test using a 100 mm visual analogue scale (0 = no use, 10 = very useful).15
The primary outcome measure was smoking cessation as measured by self report and confirmed by a salivary nicotine metabolite value of zero. Secondary outcomes were participants' perceived value of the point of care test in quitting, and reduction of tobacco use as measured by self report and the point of care test.
Fig 1 Flow of participants through trial
Statistical analysis
As the changes in salivary nicotine metabolite values for controls were not normally distributed (one sample Kolmogorov-Smirnov test, two tailed significance, P = 0.025), we used the paired t test to analyse within group differences in salivary nicotine metabolite values and the Mann-Whitney test to analyse between group differences. We used the 2 test to analyse the questionnaire results.
Results
Overall, 97 of 100 patients invited to participate in the study (48 cases, 49 controls) attended the baseline visit (fig 1). Mean ages were 32.6 (SD 11.3) and 35.3 (11.3) years, respectively, with equal numbers of men and women in each group. No participants used nicotine replacement therapy at presentation or throughout the study. We found no clinically significant difference between baseline salivary nicotine metabolite values for the cases (4.1, SD 1.3) and controls (4.3, SD 1.4). Overall, 87 participants reattended at eight weeks: four cases and six controls failed to reattend.
At eight weeks the mean salivary nicotine metabolite values for the case and control groups were 2.58 (2.0) and 4.29 (1.8), respectively (P < 0.001). For cases with a decreased nicotine metabolite value (n = 30), 10 (23%) had quit and 20 (45%) had reduced their tobacco use (fig 2). The mean reduction in nicotine metabolite values for the case group was 2.55 (1.2) between baseline and recall (P < 0.001). For cases with increased nicotine metabolite values (n = 3, 7%), the mean increase was 0.83 (2.8): 11 cases showed no change in values and four did not reattend.
Fig 2 Salivary nicotine metabolite values at baseline and eight weeks for cases (n=44) and controls (n=43) who attended the recall visit
For controls with a decreased nicotine metabolite value (n = 12), three (7%) had quit and nine (21%) had decreased their tobacco use (fig 2). The mean reduction in nicotine metabolite values for controls was 1.21 (SD 1.3). For controls with increased nicotine metabolite values (n = 13, 30%), the mean increase was 1.08 (SD 0.86) between baseline and recall: 18 showed no change, and six did not re-attend for repeat testing. Overall, the group showed no significant change in nicotine metabolite values. A higher quit rate was achieved when the point of care test was used, and overall reductions in smoking as measured by change in values for salivary nicotine metabolites in cases compared with controls (Mann-Whitney U test) were also higher (see table on bmj.com).
All 44 cases completed the questionnaire. In total, 88% thought that the point of care test provided clear, easy to interpret results, and 33% thought that the combination of observing the test, talking to the dentist, and reading the antismoking literature was the most informative and supportive method. No participants thought that sole observation of the test would modify their smoking, and 21% thought that none of the information provided would alter their perception of tobacco use.
The results from the visual analogue scale showed that 9% found the test to be of "no use," whereas 27% found it was a "very useful" aid to counselling in smoking cessation. Overall, most of the participants believed that the point of care test was beneficial. We found a significant correlation between the extent of change in the salivary nicotine metabolite values and the perceived benefit of using the test.
Discussion
World Health Organization. Annual report from WHO's tobacco free initiative. Geneva: WHO, 1999.
Tobacco Advisory Group of the Royal College of Physicians. Nicotine addiction in Britain . www.rcplondon.ac.uk (accessed Jan 2003).
Peto R, Lopez AD, Boreham J. Updated national and international estimates of tobacco-attributed mortality. www.ctsu.ox.ac.uk (accessed Mar 2004).
Russell MAH, Wilson C, Taylor C, Baker CD. Effect of general practitioners' advice against smoking. BMJ 1979;2: 231-5.
Russell MAH, Stapleton JA, Feyerabend C. Targeting heavy smokers in general practice: randomised controlled trial of transdermal nicotine patches. BMJ 1993;306: 1308-12.
Raw M, McNeill A, West R. Smoking cessation guidelines for health professionals. A guide to effective smoking cessation interventions for the health care system. Thorax 1998;(suppl 5): 1-38.
Cohen SJ, Stookey GK, Katz BP, Drook CA, Christen AG. Helping smokers quit: a randomised controlled trial with private practice dentists. J Am Dent Ass 1989;118: 41-5.
Macgregor IDM. Efficacy of dental health advice as an aid to reducing cigarette smoking. Br Dent J 1996;180: 292-6.
Smith SE, Warnakulasuriya KAAS, Feyerabend C, Belcher M, Cooper DJ, Johnson NW. A smoking cessation programme conducted through dental practices in the UK. Br Dent J 1998;185: 299-303.
Secker-Walker RH, Solomon LJ, Flynn BS, Dana GS. Comparisons of smoking cessation counselling activities of six types of health-professionals. Prev Med 1994;23: 800-8.
John JH, Thomas D, Richards D. Smoking cessation interventions in the Oxford region: changes in dentists' attitudes and reported practices 1996-2001. Br Dent J 2003;195: 270-5.
DiClemente CC, Marinhilli AS, Singh M, Bellino LE. The role of feedback in the process of health behavioural change. Am J Health Behav 2001;25: 217-27.
Jarvis MJ, Tunstall-Pedoe H, Feyerabend C, Vesey C, Saloojee Y. Comparison of tests used to distinguish smokers from non-smokers. Am J Pub Health 1997;77: 1435-8.
Cope G, Nayyar P, Holder R, Brock G, Chapple I. A near patient test for nicotine and its metabolites in saliva to assess smoking habit. Ann Clin Biochem 2000;37: 666-73.
Revell SJ, Robinson JO, Rosen M, Hogg MIJ. Reliability of linear analogue scales for evaluation of pain. Anaesthesia 1976;31: 1191-8.
Cope GF, Nayyar P, Holder R. Feedback from a point of care test for nicotine intake to reduce smoking during pregnancy. Ann Clin Biochem 2003;40: 674-9.
Department of Health publications and statistics, summary July 2004. www.dh.gov.uk/publicationsandstatistics/ (accessed Aug 2004).
Spiekerman CF, Hujoel PP, DeRouen. Bias induced by self-reported smoking on periodontitis-systemic disease associations. J Dent Res 2003;82: 345-9.
Binnie V, McHugh S, Macpherson L, Borland B, Moir K, Malik K. The validation of self-reported smoking status by analysing cotinine levels in stimulated and unstimulated saliva, serum and urine. Oral Diseases 2004;10: 287-93.
Vartiainen E, Sepp?l? T, Lillsunde P, Puska P. Validation of self-reported smoking by serum cotinine measurement in a community-based study. J Epidemiol Comm Health 2002;6: 167-70.
Warnakulasuriya KAAS, Harris CK, Scarrott DM, Watt R, Gelbier S, Peters TJ, et al. An alarming lack of public awareness towards oral cancer. Br Dent J 1999;187: 319-22.
Parrott S, Godfrey C. ABC of smoking cessation: economics of smoking. BMJ 2004;328: 947-9.(Kristian D Barnfather, general dental su)
Correspondence to: I L Chapple I.L.C.Chapple@bham.ac.uk
Objective To investigate the effect of immediate feedback from a point of care test for salivary nicotine metabolites in promoting smoking cessation and reduction in tobacco use.
Design Prospective, operator blinded, randomised controlled trial.
Setting General dental practice, London.
Participants 100 adult smokers.
Interventions Participants completed a questionnaire on smoking, undertook a clinical examination, and received counselling in smoking cessation. Saliva samples were analysed at presentation and at eight weeks for salivary nicotine metabolites using a 10 minute semiquantitative point of care test.
Main outcome measures Smoking cessation measured by salivary nicotine metabolite values (scale 0-6), patient feedback on the perceived value of the test (visual analogue scale) in quitting, and reduction in tobacco use.
Results A higher smoking quit rate was achieved with the point of care test (23% cases v 7% controls; P < 0.039), and overall tobacco use also decreased (68% cases v 28% controls; P < 0.001). Baseline values for salivary nicotine metabolites did not differ between the groups (cases, mean 4.1, SD 1.3 and 4.3, 1.4; P = 0.51). 87 participants reattended at eight weeks (44 cases, 43 controls). Mean nicotine metabolite values at eight weeks were 2.58 (2.0) for cases and 4.29 (1.8) for controls (P < 0.001).
Conclusion Incorporation of individualised personal feedback using a point of care test for salivary nicotine metabolites into a general practice based smoking cessation programme increased quit rates by 17% at eight weeks and reduced tobacco use.
The World Health Organization estimates that tobacco kills around 4.9 million people a year, and that this will rise to 10 million by 2030.1 Latest statistics indicate a 30% prevalence of smoking in UK adults, contributing to over 120 000 deaths a year and costing the health service ￡1.7bn ($3.0bn; 2.5bn).2 Of great concern is the lack of success in targeting smoking cessation among young people; by the age of 15, 28% of males and 33% of females in England smoke.3
Smoking predisposes and contributes to cytopathic changes throughout the body. Smokers have a greater incidence of coronary heart disease, myocardial infarction, peripheral vascular disease, and reduced healing rates. People with diabetes and women who use oral contraceptives are at higher risk of circulatory problems, and respiratory disease is higher among smokers. Smoking increases the risk and severity of oral cancer, periodontal disease, and premalignancy in the oral cavity.
Among healthcare professionals, dental surgeons are often in contact with the population and are in an ideal position to provide counselling and advice on smoking cessation. Even basic measures aimed at smokers who are contemplating quitting have an important effect,4 and further improvements in quit rates are reported when nicotine patches are used.5 In one study, quit rates at six and 12 weeks predicted the quit rates at 52 weeks, but only half of the participants who had quit at 6-12 weeks remained tobacco-free at one year. Another study reported 6% quit rates with the provision of intensive support and nicotine replacement therapy and concluded that if all UK general practitioners routinely offered these, up to 190 000 people could quit each year.6
Brief advice in a dental practice setting led to quit rates of 4.8-7.7%, whereas lengthier counselling, advice on nicotine replacement therapy, and the prospect of a follow-up appointment increased abstinence rates to 9.6-16.9%.7-9 A study published in the early 1990s reported that dental practitioners were less prepared than their medical colleagues to provide advice on smoking cessation,10 but recent data have shown major improvements in dental practitioners' attitudes to counselling for smoking cessation.11
Biofeedback of patient specific information on exposure to tobacco, and in particular nicotine levels, provides personalised evidence of smoke derived toxins and seems to improve patients' willingness to quit.12 Laboratory based analytical tests to evaluate smoking habit are available13 but introduce a delay in the delivery of information, particularly to the patient. Immediate access to results through point of care testing provides rapid biofeedback and facilitates the provision of treatment and patient education at the same visit. Monitoring the amount of carbon monoxide in expired air using handheld monitors discriminates between smokers and non-smokers. The short half life of carboxyhaemoglobin (2-4 hours) and its lack of specificity for tobacco, however, reduce its diagnostic accuracy.13
We have reported on a 10 minute, semiquantitative colorimetric point of care test for salivary nicotine metabolites, including cotinine, with sensitivity and specificity of 89.3% and 93.6%, respectively.14 This type of biochemical testing can also be used to overcome the physiological complexities of the inhalation, absorption, and distribution of tobacco derived chemicals throughout the body, which give each smoker a unique method of absorbing the contents of a cigarette. The saliva test (Surescreen Diagnostics; Derby, ￡3 per test) effectively condenses such variables and avoids reliance on self report by providing a single value for immediate use at the consultation visit, for future reference, and for counselling in smoking cessation.
We assessed the effect of providing smokers with visual and personalised feedback in a primary care setting on their salivary nicotine metabolite values and on quitting, and we assessed their opinions on the utility of a point of care test in helping them to quit smoking.
Participants and methods
Our study was an operator blinded, randomised controlled trial of two interventions in a sample of 100 sequentially recruited smokers within a general dental practice. We determined that with 50 participants in each group our study would have an 80% power to detect differences in quit rates of 20% or more between the two groups. KDB randomly assigned the first 100 volunteers who were current daily cigarette smokers, as reported in a self completed questionnaire, but with no specific desire to quit smoking (not a prerequisite for the study). Participants were allocated to either the case group (n = 50) or the control group (n = 50). Allocation was determined by selecting sequential numbers from two hats (one containing the participant's number (1-100) and one for group allocation) and creating a randomisation list. Participants were offered baseline assessments (enrolment), and efforts were made to ensure that members of medical staff were blinded to the participant's allocated group. We obtained written, informed consent from the participants before their inclusion in the study.
Protocol
After randomisation the participants were recalled for their baseline visit (enrolment). The study dentist (KDB) was informed of the participants' study number but remained blind to their booking details and randomisation. The practice manager allocated participants according to the randomisation schedule. The participants were given verbal counselling on smoking cessation, information about the effects of smoking on oral health (including photographs of smoking related disease), and literature packs. They were provided with a plastic container and asked to provide 2 ml of saliva by expectoration.
At this point the dentist was informed of the participants' allocated groups. Before discharge the controls were informed that they would be given their result at the next visit. The cases were shown the test procedure and given an interpretation of their salivary nicotine metabolite result before discharge. Data were entered into coded case record folders for all participants by a third member of staff, who was blind to the code allocation. The participants were recalled after eight weeks for repeat testing. They were asked if they had used, or were using, nicotine replacement therapy, as this can give a positive result on the point of care test. The operator asked participants to provide a saliva sample, which was then tested by the nurse. A third member of staff entered the results into the case record folders and a spreadsheet (Excel 97) before breaking the code and analysis.
Assay and main outcome measures
The participants were asked to refrain from consuming food or drink for 20 minutes before expectorating at least 2 ml whole, stimulated saliva into a plastic container. The saliva was analysed using a previously reported salivary nicotine metabolite assay, which utilises a colorimetric chemical reaction and direct visual comparison using a chart containing six colours, indicating varying concentrations (0-2.5 μg/ml), expressed as cotinine equivalent concentration.14 The equipment is simple and consistent with that normally present in dental and medical surgeries.
To evaluate the perceived value of the test, all cases who reattended at eight weeks completed a questionnaire to assess their opinion of the point of care test using a 100 mm visual analogue scale (0 = no use, 10 = very useful).15
The primary outcome measure was smoking cessation as measured by self report and confirmed by a salivary nicotine metabolite value of zero. Secondary outcomes were participants' perceived value of the point of care test in quitting, and reduction of tobacco use as measured by self report and the point of care test.
Fig 1 Flow of participants through trial
Statistical analysis
As the changes in salivary nicotine metabolite values for controls were not normally distributed (one sample Kolmogorov-Smirnov test, two tailed significance, P = 0.025), we used the paired t test to analyse within group differences in salivary nicotine metabolite values and the Mann-Whitney test to analyse between group differences. We used the 2 test to analyse the questionnaire results.
Results
Overall, 97 of 100 patients invited to participate in the study (48 cases, 49 controls) attended the baseline visit (fig 1). Mean ages were 32.6 (SD 11.3) and 35.3 (11.3) years, respectively, with equal numbers of men and women in each group. No participants used nicotine replacement therapy at presentation or throughout the study. We found no clinically significant difference between baseline salivary nicotine metabolite values for the cases (4.1, SD 1.3) and controls (4.3, SD 1.4). Overall, 87 participants reattended at eight weeks: four cases and six controls failed to reattend.
At eight weeks the mean salivary nicotine metabolite values for the case and control groups were 2.58 (2.0) and 4.29 (1.8), respectively (P < 0.001). For cases with a decreased nicotine metabolite value (n = 30), 10 (23%) had quit and 20 (45%) had reduced their tobacco use (fig 2). The mean reduction in nicotine metabolite values for the case group was 2.55 (1.2) between baseline and recall (P < 0.001). For cases with increased nicotine metabolite values (n = 3, 7%), the mean increase was 0.83 (2.8): 11 cases showed no change in values and four did not reattend.
Fig 2 Salivary nicotine metabolite values at baseline and eight weeks for cases (n=44) and controls (n=43) who attended the recall visit
For controls with a decreased nicotine metabolite value (n = 12), three (7%) had quit and nine (21%) had decreased their tobacco use (fig 2). The mean reduction in nicotine metabolite values for controls was 1.21 (SD 1.3). For controls with increased nicotine metabolite values (n = 13, 30%), the mean increase was 1.08 (SD 0.86) between baseline and recall: 18 showed no change, and six did not re-attend for repeat testing. Overall, the group showed no significant change in nicotine metabolite values. A higher quit rate was achieved when the point of care test was used, and overall reductions in smoking as measured by change in values for salivary nicotine metabolites in cases compared with controls (Mann-Whitney U test) were also higher (see table on bmj.com).
All 44 cases completed the questionnaire. In total, 88% thought that the point of care test provided clear, easy to interpret results, and 33% thought that the combination of observing the test, talking to the dentist, and reading the antismoking literature was the most informative and supportive method. No participants thought that sole observation of the test would modify their smoking, and 21% thought that none of the information provided would alter their perception of tobacco use.
The results from the visual analogue scale showed that 9% found the test to be of "no use," whereas 27% found it was a "very useful" aid to counselling in smoking cessation. Overall, most of the participants believed that the point of care test was beneficial. We found a significant correlation between the extent of change in the salivary nicotine metabolite values and the perceived benefit of using the test.
Discussion
World Health Organization. Annual report from WHO's tobacco free initiative. Geneva: WHO, 1999.
Tobacco Advisory Group of the Royal College of Physicians. Nicotine addiction in Britain . www.rcplondon.ac.uk (accessed Jan 2003).
Peto R, Lopez AD, Boreham J. Updated national and international estimates of tobacco-attributed mortality. www.ctsu.ox.ac.uk (accessed Mar 2004).
Russell MAH, Wilson C, Taylor C, Baker CD. Effect of general practitioners' advice against smoking. BMJ 1979;2: 231-5.
Russell MAH, Stapleton JA, Feyerabend C. Targeting heavy smokers in general practice: randomised controlled trial of transdermal nicotine patches. BMJ 1993;306: 1308-12.
Raw M, McNeill A, West R. Smoking cessation guidelines for health professionals. A guide to effective smoking cessation interventions for the health care system. Thorax 1998;(suppl 5): 1-38.
Cohen SJ, Stookey GK, Katz BP, Drook CA, Christen AG. Helping smokers quit: a randomised controlled trial with private practice dentists. J Am Dent Ass 1989;118: 41-5.
Macgregor IDM. Efficacy of dental health advice as an aid to reducing cigarette smoking. Br Dent J 1996;180: 292-6.
Smith SE, Warnakulasuriya KAAS, Feyerabend C, Belcher M, Cooper DJ, Johnson NW. A smoking cessation programme conducted through dental practices in the UK. Br Dent J 1998;185: 299-303.
Secker-Walker RH, Solomon LJ, Flynn BS, Dana GS. Comparisons of smoking cessation counselling activities of six types of health-professionals. Prev Med 1994;23: 800-8.
John JH, Thomas D, Richards D. Smoking cessation interventions in the Oxford region: changes in dentists' attitudes and reported practices 1996-2001. Br Dent J 2003;195: 270-5.
DiClemente CC, Marinhilli AS, Singh M, Bellino LE. The role of feedback in the process of health behavioural change. Am J Health Behav 2001;25: 217-27.
Jarvis MJ, Tunstall-Pedoe H, Feyerabend C, Vesey C, Saloojee Y. Comparison of tests used to distinguish smokers from non-smokers. Am J Pub Health 1997;77: 1435-8.
Cope G, Nayyar P, Holder R, Brock G, Chapple I. A near patient test for nicotine and its metabolites in saliva to assess smoking habit. Ann Clin Biochem 2000;37: 666-73.
Revell SJ, Robinson JO, Rosen M, Hogg MIJ. Reliability of linear analogue scales for evaluation of pain. Anaesthesia 1976;31: 1191-8.
Cope GF, Nayyar P, Holder R. Feedback from a point of care test for nicotine intake to reduce smoking during pregnancy. Ann Clin Biochem 2003;40: 674-9.
Department of Health publications and statistics, summary July 2004. www.dh.gov.uk/publicationsandstatistics/ (accessed Aug 2004).
Spiekerman CF, Hujoel PP, DeRouen. Bias induced by self-reported smoking on periodontitis-systemic disease associations. J Dent Res 2003;82: 345-9.
Binnie V, McHugh S, Macpherson L, Borland B, Moir K, Malik K. The validation of self-reported smoking status by analysing cotinine levels in stimulated and unstimulated saliva, serum and urine. Oral Diseases 2004;10: 287-93.
Vartiainen E, Sepp?l? T, Lillsunde P, Puska P. Validation of self-reported smoking by serum cotinine measurement in a community-based study. J Epidemiol Comm Health 2002;6: 167-70.
Warnakulasuriya KAAS, Harris CK, Scarrott DM, Watt R, Gelbier S, Peters TJ, et al. An alarming lack of public awareness towards oral cancer. Br Dent J 1999;187: 319-22.
Parrott S, Godfrey C. ABC of smoking cessation: economics of smoking. BMJ 2004;328: 947-9.(Kristian D Barnfather, general dental su)