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Biomedical subjects

J A Stapleton

Publications and source records attributed to J A Stapleton.

At least 19 recordsLinked to original sources
PubMed2001

Validation of smoking status in clinical research into inflammatory periodontal disease.

BACKGROUND: Tobacco smoking is an accepted risk factor for periodontal disease. Most studies in the periodontal literature rely on reported smoking habits which can be unreliable. This review specifically addresses this problem. METHODS: Methods of assessing tobacco smoke exposure, variation in individual smoking habits, classification of former/ex-smokers, and validation of abstinence in smoking cessation studies receive attention. DISCUSSION: Additionally, clinical studies that have examined periodontal health in subjects with validated smoking status are discussed.

Bias↗
PubMed2001

Dose-years as an improved index of cumulative tobacco smoke exposure.

In assessing the link between tobacco smoking and disease, it is important to determine longterm, cumulative exposure to tobacco smoke as accurately as possible. Conventional methods of assessing exposure to tobacco smoke each have intrinsic limitations. Self-reporting of tobacco use, and the conversion of this data to pack-years, can be prone to error due to individuals wishing to conceal smoking habits, inaccurate reporting of daily cigarette consumptions or years of smoking, and failure to take into account the variation that exists in inter-individual smoking experiences. Measurement of cotinine, a major metabolite of nicotine in humans, is a reliable method of monitoring recent doses of tobacco smoke exposure. Cotinine concentrations, however, may remain stable in smokers over the longer term. Therefore, dose-years, and more specifically cotinine-years, may represent an improved index of cumulative tobacco smoke exposure.

Biomarkers↗
PubMed2000

Dramatic decline in circulating intercellular adhesion molecule-1 concentration on quitting tobacco smoking.

The concentration of soluble ICAM-1 (sICAM-1) is significantly elevated in smokers, but it is unclear if smoking is the direct cause of elevated sICAM-1 levels, if the relationship between smoking and sICAM-1 level is dose-dependent, and if smoking cessation may lead to a decline in sICAM-1. We sought to clarify the relationship between smoking and sICAM-1 in a group of smokers who quit smoking for 1 year (n = 30) and a control group who continued to smoke (n = 30). A dose-dependent relationship between plasma sICAM-1 concentration and daily cigarette consumption (P = 0.02), plasma cotinine level (P = 0.02), and expired CO level (P = 0.007) was observed at baseline (n = 60). The mean change in sICAM-1 concentration after 52 weeks was greater for quitters than for continuing smokers (mean difference = -71.1 ng/ml, P < 0.001). The influence of smoking on sICAM-1 needs to be carefully considered in clinical trials. Soluble ICAM-1 remains bioactive and may contribute to pathogenic processes; therefore, reduction in the concentration of circulating ICAM-1 molecules may directly contribute to the health benefits associated with smoking cessation.

Adult↗
PubMed2000

Circulating concentrations of C-reactive protein and total sialic acid in tobacco smokers remain unchanged following one year of validated smoking cessation.

BACKGROUND: Elevated plasma concentrations of C-reactive protein (CRP) and total sialic acid (TSA) have been associated with increased cardiovascular risk. Additionally, levels of both CRP and TSA have been reported to be significantly elevated in smokers. However, it is not clear if the raised TSA and CRP levels noted in smokers are directly attributable to the smoking experience, or if they may be elevated due to a secondary mechanism(s), such as smoking-induced tissue inflammation. SUBJECTS AND METHODS: We measured the plasma concentration of CRP and TSA in a group of smokers at baseline and following one year of validated smoking cessation (n = 30) and in a control group of tobacco users who continued to smoke over the year (n = 30). RESULTS: The baseline concentration of TSA and CRP was 67.2 mg dL(-1) and 1.91 mg L(-1), respectively (n = 60). No significant dose-dependent relationship was noted between baseline CRP or TSA concentration and either plasma cotinine, expired-air CO or daily cigarette consumption. There was no difference in the mean change in CRP level in the quitters over one year (- 0.2 mg L(-1)) compared to the continuing smokers (+ 0.5 mg L(-1)), P = 0.80, or in the change in concentration of TSA in the quitters (- 2.7 mg dL(-1)) compared to the continuing smokers (+ 0.4 mg dL(-1)), P = 0.26. CONCLUSIONS: As the circulating concentrations of both CRP and TSA remain unchanged following one year of smoking cessation, these results would suggest that the elevated levels noted in smokers are not directly attributable to tobacco use and are more likely to be elevated due to a secondary process that is yet to be established.

Adult↗
PubMed2000

Plasma concentrations of reputed tumor-associated soluble CD44 isoforms (v5 and v6) in smokers are dose related and decline on smoking cessation.

There is some evidence to suggest that smoking may affect circulating levels of CD44 (sCD44) molecules. Therefore, we investigated the effect of smoking on the circulating level of sCD44 by comparing the change in total sCD44, sCD44v5, and sCD44v6 concentrations over 1 year in a group of people who quit smoking (n = 30) and a control group of people who continued to smoke (n = 30). Smoking status and compliance were monitored by analysis of plasma cotinine and expired CO levels and also by self-reported tobacco use. We show a dose-dependent relationship between smoke intake and baseline plasma concentrations of reputed tumor-associated CD44 variant isoforms (sCD44v5 and sCD44v6) in smokers (n = 60). There was a significant decline in the level of both sCD44v5 and sCD44v6 in quitters as compared with continuing smokers [-13.2 (95% confidence interval, -7.6 to -18.8; P < 0.001) and -62.2 ng/ml (95% confidence interval, -33.9 to -90.6; P < 0.001), respectively], but not in the total sCD44 concentration. These results show that the increased concentrations of sCD44v5 and sCD44v6 in smokers are dose related and reversible and suggest that the attributed diagnostic specificity and prognostic value of sCD44 molecules in malignant and inflammatory disease may be affected by smoking status.

Adult↗
PubMed1999

Prescription of transdermal nicotine patches for smoking cessation in general practice: evaluation of cost-effectiveness.

BACKGROUND: The 1998 UK government White Paper Smoking Kills emphasises that normal practice should be for general practitioners (GPs), practice nurses, and others to offer advice and support to smokers in their efforts to stop. However, GPs are not allowed to write NHS prescriptions for nicotine-replacement therapy, even though this is the only effective pharmaceutical treatment available in the UK. We estimated the cost-effectiveness, for the NHS, of allowing GPs to prescribe transdermal nicotine patches for up to 12 weeks. METHODS: We used data from a randomised, placebo-controlled efficacy trial of nicotine patches and a survey of associated resource use in 30 GP surgeries in 15 English counties. We calculated the health benefit of nicotine-patch treatment in number of life years that would be saved by stopping smoking at various ages, and used an abstinence-contingent treatment model to calculate the incremental cost per life year saved by GP counselling with nicotine-patch treatment over GP counselling alone. Cost effectiveness was assessed on the basis that GPs would provide repeat NHS prescriptions for up to 12 weeks if the treatment was proving successful. FINDINGS: If GPs were allowed to prescribe transdermal nicotine patches on the NHS, for up to 12 weeks, the incremental cost per life year saved would be: Pound Sterling 398 per person younger than 35 years; Pound Sterling 345 for those aged 35-44 years; Pound Sterling 432 for those aged 45-54 years; and Pound Sterling 785 for those aged 55-65 years. INTERPRETATION: The low cost per life year saved would make GP intervention against smoking a cost-effective life-saving treatment. The priniciples of the government White Paper could be cost-effectively extended into general practice to reduce smoking and smoking-related illnesses.

Administration, Cutaneous↗
PubMed1998

Nicotine availability from Eclipse tobacco-heating cigarette.

A cigarette which heats rather than burns tobacco (Premier) was introduced in 1988, but was unacceptable due to unpleasant taste and low nicotine intake. We examined availability of nicotine from a new version (Eclipse), in the same four subjects as our earlier Premier study. Average blood nicotine boosts of 23.7 and 17.8 ng/ml were obtained from smoking a first and second Eclipse. This substantially exceeds intake from Premier (boost 13 ng/ml) and that obtained by heavy smokers from conventional brands (boost 12-15 ng/ml). Eclipse (or similar product) may be the best option for averting Peto's dire warnings of rising millions of annual smoking deaths in the 2020s, and its potential for large-scale, long-term switching warrants further study.

Adult↗
PubMed1997

Mood and physiological effects of subcutaneous nicotine in smokers and never-smokers.

This study compared the effect of subcutaneous nicotine injections (2 x 0.3 mg and 2 x 0.6 mg) with saline on subjective and physiological measures in 18 never-smokers and 18 smokers (24-h nicotine deprived), under conditions of rest and cognitive testing. Prior to the injections the mood of the smokers had deteriorated to a level significantly below that of the never-smokers as a result of tobacco withdrawal. Cognitive tests caused reductions in calmness and increased alertness but there was no evidence of nicotine improving mood in either group under either condition. The 0.6 mg dose worsened mood in never-smokers and caused unpleasant symptoms (e.g. dizziness and arm pain) in both groups. Compared with smokers, never-smokers experienced stronger symptoms of nicotine toxicity and a greater reduction in alertness in response to the 0.6 mg dose, suggesting chronic tolerance to some nicotine effects in smokers. Nicotine produced similar increases in heart rate and decreases in finger pulse volume in both groups. Our results imply that if nicotine has a mood enhancing effect it occurs only after tolerance has been acquired to its primary adverse effects, and that its ability to reverse the mood deterioration caused by tobacco withdrawal is susceptible to situational factors such as our experimental conditions.

Adult↗
PubMed1995

Naltrexone, smoking behaviour and cigarette withdrawal.

In order to examine the role of endogenous opioids in the reinforcing effects of nicotine, a double-blind, placebo-controlled, cross-over design was used to study the effects of the opiate antagonist, naltrexone, on smoking behaviour and cigarette withdrawal in 12 heavy smokers. Although naltrexone (50 mg) appeared to reduce the perceived difficulty of abstaining during 24-h cigarette withdrawal, other withdrawal symptoms were unaffected. Naltrexone also had no effect on a variety of biochemical and behavioural measures of nicotine intake or on subjective satisfaction and enjoyment from the first cigarette smoked after 24-h abstinence. Similarly naltrexone (100 mg) had no effect on smoking behaviour, nicotine intake or satisfaction from smoking during a 48-h period of ad libitum smoking. However, during the ad libitum smoking period naltrexone caused mood changes of the kind that occur during tobacco withdrawal. Since nicotine intake and smoking behaviour were unaffected, the mood changes are unlikely to have been mediated by blockade or any other form of opioid interaction with nicotinic mechanisms. These findings provide evidence against the notion that the endogenous opioids are involved in mediating the reinforcing properties of nicotine in smokers under normal conditions.

Adult↗
PubMed1995

Dose effects and predictors of outcome in a randomized trial of transdermal nicotine patches in general practice.

The transdermal nicotine patch has proved an effective aid to smoking cessation. The ease of securing good compliance gives it a potential advantage over nicotine gum as an adjunct to brief advice and support in primary care settings where the major public health impact is obtained. In a preliminary report of half the sample of a randomized placebo controlled trial, we showed the patch to be effective in a general practice setting. We report here the definitive results of the full sample, including dose effects, predictors of outcome and other issues of theoretical and practical interest. A total of 1200 heavy smokers (> or = 15 per day), attending 30 general practices in 15 English counties received brief GP advice, a booklet and 16 hours per day patch treatment for 18 weeks. Dose increase and abrupt vs. gradual reduction of patch dosage were also randomized and follow-ups conducted at 1, 3, 6, 12, 26 and 52 weeks. Outcome was measured by self-reported complete abstinence from week 3 to 52 with biochemical validation at all follow-up points. Nicotine patch treatment doubled the rate of continuous abstinence up to 1 year (nicotine 9.6%, placebo 4.8%, p < 0.01); it most likely worked by reducing withdrawal symptoms. It enhanced cessation during the first week and reduced relapse during the second week. The dose increase after week 1 produced no sustained increase in cessation. Gradual reduction was no better at preventing relapse than abrupt withdrawal of patches after week 12. Whether relapse would have increased by ending treatment at some point between weeks 3 and 12 was not tested. Although pre-treatment dependence on cigarettes was prognostic of failure, the patches were equally helpful to both highly and less dependent smokers. Patches were particularly helpful to smokers with pre-treatment subclinical dysthymic symptoms. All but one of the 96 subjects eventually achieving long-term abstinence in the study quit during the first week of cessation.

Administration, Cutaneous↗
PubMed1993

Targeting heavy smokers in general practice: randomised controlled trial of transdermal nicotine patches.

OBJECTIVES: (a) To evaluate the efficacy of transdermal nicotine patches as an aid to stopping smoking when used as an adjunct to brief advice and support in a general practice setting; (b) to see whether an increase in nicotine patch dosage enhances the rate of initial cessation. DESIGN: Randomised double blind placebo controlled parallel group study with one year of follow up. SETTING: 30 general practices in 15 English counties. SUBJECTS: 600 dependent heavy smokers (> or = 15 cigarettes daily) who were well motivated to give up. INTERVENTIONS: Brief general practitioner advice, booklet, and 16 hours per day patch treatment for 18 weeks with brief support and follow up at one, three, six, 12, 26, and 52 weeks. MAIN OUTCOME MEASURES: Self reported complete abstinence for up to one year with biochemical validation at all follow up points. RESULTS: Nicotine patches reduced the severity of craving and adverse mood changes in the first weeks of withdrawal and doubled the rate of initial cessation at week 3 (nicotine group 36% of patients (144/400), placebo group 16.5% of patients (33/200)) and of continuous abstinence throughout one year (nicotine group 9.3% (37), placebo group 5.0% (10)). A dose increase at week 1 among patients experiencing difficulty in quitting increased the proportion who achieved abstinence at week 3. There were no adverse systemic effects attributable to nicotine, but the incidence of moderate or severe local irritation or itching at the patch site was 16.4% (63 patients), compared with 3.8% (seven) with placebo. CONCLUSION: Transdermal nicotine patches used as an adjunct to brief advice and support in a general practice setting are an effective aid to long term cessation of smoking in highly dependent smokers.

Administration, Cutaneous↗
PubMed1993

Glycerol particle cigarettes: a less harmful option for chronic smokers.

In 20 smokers who switched to a new type of virtually tar free cigarette for three days, average nicotine intake was reduced by 44%, carbon monoxide intake increased by 19%, while estimated tar intake was reduced by about 90%. Such cigarettes pose substantially less risk of cancer and chronic obstructive lung disease than conventional cigarettes, and their acceptability and safety could be improved by increasing nicotine yield, reducing carbon monoxide yield, and improving the flavour.

Carbon Monoxide↗
PubMed1992

Randomised controlled trial of nasal nicotine spray in smoking cessation.

Studies with nicotine chewing gum and nicotine skin patches indicate that nicotine replacement can help people to give up smoking. The rapidity with which nicotine is absorbed when given as a nasal spray suggests that it might be effective for those for whom the other means of replacement are too slow. The efficacy and safety of a nasal nicotine spray as an adjunct to group treatment for stopping smoking were assessed in a randomised, double-blind, placebo-controlled trial in which 227 cigarette smokers attending the Maudsley Hospital Smokers Clinic received 4 weeks of supportive group treatment plus active nicotine (0.5 mg per shot) or placebo nasal spray. The main end-point was biochemically validated complete abstinence from smoking from the third week of group treatment until the 12-month follow-up. Side-effects were assessed by self-reports and, where necessary, by physical examination. Of subjects assigned to active treatment 26% (n = 30) were validated abstinent throughout the year, compared with 10% (n = 11) of those assigned to placebo (relative abstinence rate 2.6, 95% CI 1.5-4.5, p less than 0.001). The advantage of the active spray was greatest in the heaviest smokers. Plasma nicotine concentrations from the spray were typically between one-half and three-quarters of baseline smoking levels. Tobacco-withdrawal symptoms, craving for cigarettes, and weight gain in abstinent subjects were reduced by the active spray. Minor irritant side-effects were frequent in both active and placebo sprays, but only 2 subjects had the spray discontinued as a result. No serious adverse effects were encountered. Nasal nicotine spray combined with supportive group treatment is an effective aid to smoking cessation.

Administration, Intranasal↗
PubMed1989

Nicotine gum use and outcome in a general practitioner intervention against smoking.

In a general practitioner intervention against smoking (employing nicotine chewing gum) smokers who used more than a box of gum were, prior to the intervention, more motivated to quit smoking and more dependent than those who did not use more than a box. They were also older. Even after controlling for demographic, dependence, motivational and previous success factors, those who used more than a box of gum had a significantly enhanced probability of success compared with other smokers. Although causal conclusions cannot be drawn from these analyses, stress on the importance of persistence in use of the gum is recommended.

Adult↗
PubMed1989

Prospective study of factors predicting uptake of smoking in adolescents.

Risk factors for the uptake of cigarette smoking were examined prospectively in 2159 non-smoking secondary schoolchildren aged 11-13 who participated in a survey in 1983 and were followed up 30 months later, by which time 35 per cent had taken up smoking. In a multivariate logistic model, the strongest predictors to emerge were prior experimentation with cigarettes and sex, with more girls (41%) than boys (30%) starting to smoke. Other predictors of taking up smoking were being uncertain about smoking in the future, reporting having been drunk, having a boy or girl friend, believing teachers and friends would not mind if they took up smoking, and giving lower estimates of prevalence of smoking among teachers. Parental smoking behaviour and attitudes, beliefs about the effects of smoking on health, opinions about smoking and perceived strictness of parents did not predict take up of smoking when other variables were controlled for. The odds of taking up smoking varied from 0.24 (risk = 0.19) for a child with the most favourable combination of risk factors to 3.49 (risk = 0.78) for a child with the worst prognosis. These results differ from those of many cross sectional studies and hence indicate the importance of a prospective approach to this type of research.

Adolescent↗
PubMed1989

Nicotine intake in young smokers: longitudinal study of saliva cotinine concentrations.

Smoking habits and smoke intake were studied over three consecutive years in 197 girls, initially aged 11 to 14 years. Saliva cotinine concentrations in girls who were smokers throughout the three years increased over each year of the study, the greatest increase occurring during movement from occasional to daily smoking. Cigarette consumption also increased over the two years. For a group of continuing daily smokers (n = 23), inhalation of smoke per cigarette as indexed by the ratio of cotinine concentration to average daily cigarette consumption did not change over time. Cotinine concentrations in 16 girls who were smoking on a daily basis within a year of starting to smoke suggested the early development of inhalation. Our findings suggest that young smokers learn to inhale cigarette smoke very early in their smoking careers, that further increases in smoke intake mainly reflect increased cigarette consumption, and that the pharmacological effects of nicotine are already important in reinforcing their smoking.

Adolescent↗
PubMed1988

District programme to reduce smoking: can sustained intervention by general practitioners affect prevalence?

A total of 101 general practitioners in 27 practices in inner London took part in a quasi-experimental study designed to examine whether a brief intervention applied to all smokers seen by general practitioners and sustained on a continuous basis could in time have a cumulative effect and reduce the prevalence of smoking among their patients. Of 21 practices approached in our local district (Camberwell), seven were willing to undertake brief intervention with support from the smokers' clinic (SBI), four opted for intervention without support (BI), and six acted as usual care controls. A further 10 out of 12 practices approached in South Hammersmith provided an unselected group of usual care controls. A series of six cross-sectional surveys were conducted over a three-year period. Each survey consisted of all adult patients attending to see a doctor during a defined two-week period, sample sizes averaging just over 9000 per survey. The estimated decline in self-reported smoking prevalence over the 30-month period following the start of intervention was 5.5% (from 36.4% to 30.9%) in the SBI group compared with 2.1% for BI and 2.8% and 3.0% in the two usual care control groups, the decline in the SBI group being significantly greater than in the other groups which did not differ significantly between each other. These interim results provide encouraging evidence that brief intervention by general practitioners with support and back-up from a local smokers' clinic can, when sustained on a continuous basis, reach sufficient smokers to reduce smoking prevalence in their practice populations. However, firm conclusions must await longer periods of observation now that the other Camberwell practices have adopted the SBI procedures.

Age Factors↗