c-Reactive protein and the metabolic syndrome in older Chinese: Guangzhou Biobank Cohort Study

OBJECTIVE

To examine the association between serum c-reactive protein (CRP) concentration and the metabolic syndrome (MS) using the International Diabetes Federation Metabolic Syndrome Guidelines (April, 2005) definition in an older Chinese population.

METHODS

Three thousand and fourteen men and 7275 women aged 50-85 years were recruited and received a full medical check-up including measurement of blood pressure, obesity indices, fasting total, LDL-, HDL-cholesterol, triglycerides, glucose and c-reactive protein. Data describing socioeconomic and lifestyle factors was also collected.

RESULTS

Vascular risk factors including waist circumference, weight gain and waist gain since the age of 18, body mass index, waist-hip-ratio, triglyceride, HDL-cholesterol, and systolic and diastolic blood pressures were positively associated with CRP in both men and women (p from <0.001 to 0.016). Compared to those without MS components, adjusted odds ratios for having elevated CRP increased in those with the MS or its components compared those without MS or components (all p<0.001), except for the low HDL-cholesterol in both genders and raised fasting glucose in men. Similarly, the risk of elevated CRP increased with escalating MS components even after adjustment of a range of potential confounders.

CONCLUSIONS

There is a strong relationship between CRP and the constellation of MS components and associated vascular risk in this older Chinese population.

Implications of increased weight and waist circumference on vascular risk in an older Chinese population: the Guangzhou Biobank Cohort Study

BACKGROUND

The relationships between weight and waist on vascular risk are well described, but the long-term impact of these parameters is less clearly defined, particularly in Chinese populations.

METHODS

Ten thousand four hundred and ten older subjects (50-85 years) were recruited and blood pressure, anthropometric, and fasting vascular risk factors measured. Socioeconomic and demographic data, including self-reported weight and waist gain since 18 years. The association of weight and waist gain with these vascular risk factors was analysed.

RESULTS

Weight, and particularly waist gain were associated with a more adverse vascular risk factor profile, with the most adverse profile associated with gains in both weight and waist. Anthropometric gains were associated with increased risk even in non-obese subjects (p<0.05). Even after adjustment for a range of demographic and socioeconomic factors, waist gain was associated with additional risk of having the metabolic syndrome and its components and self-reported vascular disease in those centrally obese subjects (p<0.05 for all).

CONCLUSION

Increased weight and waist increased the level of vascular risk factors and self-reported disease in both non-obese and obese subjects. The high prevalence of vascular risk factors in this population forewarns of a major developing health burden in the rapidly modernising 1.2 billion Chinese population.

Passive smoking exposure and risk of COPD among adults in China: the Guangzhou Biobank Cohort Study

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a leading cause of mortality in China, where the population is also exposed to high levels of passive smoking, yet little information exists on the effects of such exposure on COPD. We examined the relation between passive smoking and COPD and respiratory symptoms in an adult Chinese population.

METHODS

We used baseline data from the Guangzhou Biobank Cohort Study. Of 20 430 men and women over the age of 50 recruited in 2003-06, 15,379 never smokers (6497 with valid spirometry) were included in this cross-sectional analysis. We measured passive smoking exposure at home and work by two self-reported measures (density and duration of exposure). Diagnosis of COPD was based on spirometry and defined according to the GOLD guidelines.

FINDINGS

There was an association between risk of COPD and self-reported exposure to passive smoking at home and work (adjusted odds ratio 1.48, 95% CI 1.18-1.85 for high level exposure; equivalent to 40 h a week for more than 5 years). There were significant associations between reported respiratory symptoms and increasing passive smoking exposure (1.16, 1.07-1.25 for any symptom).

INTERPRETATION

Exposure to passive smoking is associated with an increased prevalence of COPD and respiratory symptoms. If this association is causal, we estimate that 1.9 million excess deaths from COPD among never smokers could be attributable to passive smoking in the current population in China. Our findings provide strong evidence for urgent measures against passive smoking in China.

A randomized controlled trial of smoking cessation for pregnant women to test the effect of a transtheoretical model-based intervention on movement in stage and interaction with baseline stage

OBJECTIVES

To examine whether, as predicted by the transtheoretical model (TTM), stage-matched interventions will be more effective than stage-mismatched interventions.

DESIGN

Randomized controlled trial of smoking cessation advice to pregnant smokers.

METHODS

Pregnant women currently smoking at 12 weeks gestation were enrolled in a pragmatic three-arm trial of TTM-based interventions to help them stop smoking. One arm constituted standard midwifery advice and a self-help leaflet on stopping smoking, which is generally appropriate for women in preparation. Two arms were TTM-based. Differences in positive movement in stage towards quitting from enrolment to 30 weeks gestation and 10 days post-partum were calculated for each arm of the trial. We then examined whether, as predicted from the TTM, the relative benefit of the TTM-based intervention was greater for women in precontemplation and contemplation, for whom the control intervention was stage-mismatched, than for women in preparation, for whom the control intervention was stage-matched.

RESULTS

Women in the TTM-based arms were statistically significantly more likely to move forward in stage than were women in the control arm. Contrary to the TTM-derived hypothesis, the greater relative benefit of the TTM-based intervention was seen for women in preparation stage at baseline, rather than women in precontemplation and contemplation.

CONCLUSIONS

The TTM-based intervention was more effective in stage movement, but this could be due to its greater intensity. The failure to confirm that stage-matching was important casts doubt on the validity of the TTM in explaining smoking cessation behaviour in pregnancy.

Association of the metabolic syndrome with vascular disease in an older Chinese population: Guangzhou Biobank Cohort Study

OBJECTIVE

To assess the prevalence of the metabolic syndrome (MS) and relative associations with vascular disease in an older Chinese population using the US National Cholesterol Education Program: Adult Treatment Panel (NCEP: ATP III) and International Diabetes Federation (IDF) definitions.

DESIGN

Cross-sectional study.

SUBJECTS

A total of 3035 men and 7291 women aged 50 to 85 yr recruited from Guangzhou, China.

MEASUREMENTS

All participants received a full medical check-up including measurement of blood pressure, obesity indices, fasting total, LDL-, HDL-cholesterol, triglycerides (TG) and glucose levels. Demographic information and self-reported history of physician-diagnosed coronary heart disease (CHD), stroke and myocardial infarction (MI) were collected through standardized interview.

RESULTS

The estimates under the two definitions differed substantially, with the age standardized prevalence of MS 15.57% using the NCEP: ATP III definition and 25.81% using the IDF definition. Among all participants, 80.23% were similarly classified using both definitions. The association between self-reported CHD, stroke and MI and the MS defined by the IDF definition was stronger than that by the NCEP: ATP III.

CONCLUSIONS

The IDF compared to the ATP III definition shows a stronger association with the MS and associated vascular disease in Chinese. The prevalence of the MS is alarmingly high in this older Chinese population. Comprehensive strategies are needed for prevention and treatment of the MS to reduce the increased societal burden of cardiovascular disease in China.

Parity and the metabolic syndrome in older Chinese women: the Guangzhou Biobank Cohort Study

OBJECTIVE

To examine whether parity or gravidity contributes to the development of the metabolic syndrome (MS).

METHODS

The first phase of the Guangzhou Biobank Cohort Study recruited 7352 women and 3065 men aged 50-93 years in 2003-4. Data on the number of live births and pregnancies, other reproduction-associated factors and socioeconomic and lifestyles factors were collected by standardized interview. The MS components were determined through physical examination and measurement of fasting blood samples. MS was identified if waist circumference was >or= 90 cm for men or >or= 80 cm for women, plus any two of: (a) raised triglyceride (TG) level (1.7 mmol/l) or specific treatment for this lipid abnormality; (b) reduced high density lipoprotein (HDL)-cholesterol (< 1.03 mmol/l in males or < 1.29 mmol/l in females) or specific treatment for this lipid abnormality; (c) raised blood pressure (BP, systolic BP >or= 130 mmHg or diastolic BP >or= 85 mmHg) or hypertension therapy; and (d) raised fasting glucose (>or= 5.6 mmol/l) or previously diagnosed type 2 diabetes.

RESULTS

Before adjustment for potential confounders, we found associations between the number of births and lifestyle and socioeconomic factors in both sexes. However, in women, but not in men, body mass index (BMI), waist-hip ratio, triglyceride and glucose were positively associated with the number of birth after adjusting for a range of potential confounders. The age-adjusted prevalence of the MS increased with the number of births and pregnancies in women, but the gradient for birth was steeper than that for pregnancies [odds ratio change per birth 1.16, 95% confidence interval (CI) 1.11-1.22, P < 0.001; odds ratio change per pregnancy 1.11, 95% CI 1.06-1.16, P < 0.001], although attenuating the association adjustment did not affect the significance of these findings. There was no association in men with regard to the number of their partners' live births given the same analysis and similar shared living background with the women.

CONCLUSION

Higher parity or gravidity was associated with a consistent increase in the risk of MS in Chinese women. As the association persisted after adjustment for lifestyle factors and there was no association between the risk of MS and the number of births associated with the partners of the males, the association in women may represent a biological response to pregnancy.

Snoring and vascular risk factors and disease in a low-risk Chinese population: the Guangzhou Biobank Cohort Study

STUDY OBJECTIVE

Snoring is a common condition, but data describing the relationship between snoring and vascular disease is very limited in Asian populations. We therefore describe the association between snoring and vascular disease and associated risk factors.

DESIGN

Cross-sectional study of baseline data from the Guangzhou Biobank Cohort Study.

SETTING

Community-based elderly association from Guangzhou, China.

PARTICIPANTS

10413 Chinese subjects (50-85 years of age).

MEASUREMENTS

Self-reported snoring status and frequency and frequency of daytime tiredness were collected by questionnaire, as were demographic and socioeconomic data, disease histories, and potential confounders, such as smoking and alcohol consumption. Anthropometry, blood pressure, and fasting glucose and lipid profile were also measured.

RESULTS

Self-reported snoring frequency was identified in 8325 (80.0%) subjects, with 51.6% reporting that they snored, of whom 15.5% were daily snorers. Increasing prevalence of snoring showed a clear positive relationship with cardiovascular risk factors, including age, obesity, blood pressure, and lipid levels (p < .001 for all). The prevalence of self-reported vascular-disease history was low but significantly associated with increasing snoring frequency. Logistic regression showed that snoring frequency was an independent predictor of vascular-disease history (odds ratios [95% confidence intervals] 1.68 [1.32-2.13] for daily snorers compared with the never-snorer reference group), of the metabolic syndrome (2.16 [1.88-2.49]) and each of its components (hypertension [1.37 (1.20-1.56)], and of dyslipidemia [1.22 (1.07-1.40)], central obesity [2.39 (2.08-2.76)], and diabetes [1.30 (1.09-1.56)]) after adjustment for potential confounders.

CONCLUSION

Increasing snoring frequency was associated with an increasing prevalence of risk factors and self-reported vascular disease. Snoring may a useful marker for increased risk of vascular disease.

Does smoking influence survival in cancer patients through effects on respiratory and vascular disease?

Patients with cancers caused by smoking may die because they continue to smoke even after diagnosis of a cancer caused by smoking. We investigated differences in cause-specific mortality between patients diagnosed with smoking-related and non-smoking-related cancers. The causes of death were classified as smoking-related cancer, non-smoking-related cancer, respiratory or vascular disease, and all other causes. We studied all 220 089 people diagnosed with cancer in Scotland between 1986 and 1996, aged between 20 and 85 years, with last follow-up on 31 December 1999. There was a moderate excess risk of dying from respiratory and vascular causes in those with smoking-related cancers, which did not fall with time since diagnosis, consistent with continued smoking by these patients. Mortality among cancer patients might fall if more assistance in stopping smoking was provided for patients who have smoking-related cancers.

Systemic hypertension and glaucoma: mechanisms in common and co-occurrence

AIMS

To determine whether systemic hypertension and glaucoma might coexist more often than expected, with possible implications for treatment.

METHODS

Case-control study using general practitioner database of patients with glaucoma matched with controls for age and sex.

RESULTS

Hypertension was significantly more common in the 27,080 patients with glaucoma (odds ratio 1.29, 95% confidence intervals 1.23 to 1.36, p<0.001) than in controls. Treatment by oral beta blockade appeared to protect from risk (odds ratio 0.77, 95% CI 0.73 to 0.83, p<0.0001), but oral calcium channel antagonists or angiotensin converting enzyme (ACE) inhibitors did not (odds ratios 1.34, 1.24 to 1.44 and 1.16 1.09-1.24, respectively, p<0.0001 in each case). Oral corticosteroid treatment was associated with enhanced risk (odds ratio 1.78, 1.61 to 1.96).

CONCLUSION

Common pathogenetic mechanisms in ciliary and renal tubular epithelia may explain coincidence of glaucoma and systemic hypertension. The choice of cardiovascular treatment, could substantially influence glaucoma incidence, with beta blockade protecting and ACE inhibitors or calcium channel blockers not affecting underlying risk.

The influence of in-pregnancy smoking cessation programmes on partner quitting and women's social support mobilization: a randomized controlled trial [ISRCTN89131885]

BACKGROUND

Smoking cessation interventions in pregnancy could influence a woman's social behaviour and her partner's smoking behaviour, but this has not been examined in any published randomized trials.

METHOD

918 women smoking at booking for antenatal care were enrolled in a cluster-randomized trial of three interventions: standard care, self-help manual and enhanced stage-based counselling, or self-help manual, enhanced stage-based counselling and use of an interactive computer program. The outcomes were change in social support received by women between booking for maternity care and 30 weeks gestation and 10 days postpartum and reported cessation in the woman's partner at these times.

RESULTS

Few pregnant women's partners stopped smoking (4.1% at 30 weeks of gestation and 5.8% at 10 days postpartum) and the probability of quitting did not differ significantly by trial arm. Women's scores on the Inventory of Socially Supportive Behaviors showed a slight decline from booking to 30 weeks gestation, and a slight increase to 10 days postpartum, but these changes did not differ significantly by trial arm.

CONCLUSION

The stage-based interventions tested in this trial aimed partly to influence women's mobilization of support and might have influenced partners' quitting, but there was no evidence that they did so. Given that women and their partners often stopped smoking together, future interventions to prevent smoking in pregnant women could encourage both partners to quit together.

Is advice to stop smoking from a midwife stressful for pregnant women who smoke? Data from a randomized controlled trial

BACKGROUND

There are no randomized trials examining whether intensive advice to pregnant smokers is more stressful than standard care.

METHOD

Nine hundred eighteen U.K. women currently smoking on commencing antenatal care were randomized into three arms. Women in Arm A received one episode of brief advice to stop smoking. Women in Arm B were assessed for stage of change and worked through an exercise in self-help manuals on three occasions. Women in Arm C used a 20-min interactive computer program three times in addition to the intervention women in Arm B received. Stress was assessed by the change in score on the Perceived Stress Scale (PSS) from baseline to 30 weeks gestation, the month before delivery, and 10 days postpartum.

RESULTS

There were small and not significant differences in the changes in PSS between the arms at all outcome times. There was no evidence that the importance women attached to pleasing their midwife by stopping, having failed to quit, or nulliparity modified the effect of intensive advice on change in stress levels. CONCLUSIONS.: Intensive advice to stop smoking was not associated with increases in stress. Advice and support for pregnant women to stop smoking should be given without fear of causing stress.

Is inter-school variation in smoking uptake and cessation due to differences in pupil composition? A cohort study

The aims of this study were to determine if inter-school variation in smoking prevalence was due to differences in pupil composition or other school-level factors. A cohort of 13-14-year-olds (n = 7147) from 52 schools was followed-up 1 year later. Random effects logistic regression was used to examine school variation in smoking uptake and cessation, with and without adjustment for pupil composition. Inter-school variation in smoking prevalence is not caused by differences in pupil composition but is due to differences in the onset of smoking arising because of unmeasured school contextual or collective factors operating on pupils' decisions.

Does stage-based smoking cessation advice in pregnancy result in long-term quitters? 18-month postpartum follow-up of a randomized controlled trial

AIMS

To evaluate the effect on quitting smoking at 18 months postpartum of smoking cessation interventions based on the Transtheoretical Model (TTM) delivered in pregnancy compared to current standard care. It has been claimed that TTM-based interventions will continue to create quitters after the end of the intervention period.

DESIGN

Cluster randomized trial.

SETTING

Antenatal clinics in general practices in the West Midlands, UK.

PARTICIPANTS

A total of 918 pregnant smokers originally enrolled in the trial, of which 393 women were followed-up at 18 months postpartum.

INTERVENTIONS

One hundred general practices were randomized into the three trial arms. Midwives in these practices delivered three interventions: A (standard care), B (TTM-based self-help manuals) and C (TTM-based self-help manuals plus sessions with an interactive computer program giving individualized smoking cessation advice).

MEASUREMENTS

Self-reported continuous and point prevalence abstinence since pregnancy.

FINDINGS

When combined together, there was a slight and not significant benefit for both TTM arms compared to the control, with an odds ratio (OR) 95% confidence interval (CI) of 1.20 (0.29-4.88) for continuous abstinence. For point prevalence abstinence, the OR (95%CI) was 1.15 (0.66-2.03). Seven of the 54 (13%) women who had quit at the end of pregnancy were still quit 18 months later, and there was no evidence that the TTM-based interventions were superior in preventing relapse.

CONCLUSIONS

The TTM-based interventions may have shown some evidence of a short-term benefit for quitting in pregnancy but no benefit relative to standard care when followed-up in the longer-term.

A methodological and substantive review of the evidence that schools cause pupils to smoke

The objectives of this review were to examine whether smoking prevalence varies between schools independently of health promotion programmes and pupil composition, to show which school characteristics are responsible for this variation, and to examine the methodological adequacy of such studies. Searches for published studies were performed on medical, educational and social science databases, relevant articles' reference lists, and citation searches. Any study was included that described inter-school variation in smoking prevalence, or related such variation to school characteristics. A model relating pupil smoking to school, neighbourhood, and pupil characteristics unlikely and likely to be influenced by school was used to examine the adequacy of control of confounding by pupil composition. Data from studies were combined qualitatively considering methodological adequacy to examine the relation of smoking prevalence to school characteristics. Theoretical frameworks underpinning the choice of school characteristics and postulated relationships between these characteristics and smoking prevalence were described. There were large variations in smoking prevalence between ostensibly similar schools. Evidence that pupil composition did not cause this was weak, because all studies had methodological problems, including under control of relevant pupil compositional factors and over control of factors likely to represent the mechanism through which schools influence pupils' smoking. There was little evidence that elements of tobacco control policy other than bans and enforcement deterred smoking. Academic practice and school ethos were related to smoking. Academically selective schools did not influence smoking, once pupil composition was controlled. There was one study on neighbourhood influences, which were unrelated to smoking. Studies frequently offered little or no theoretical justification for associating school characteristics with smoking. Some aspects of school influence pupils' smoking, probably independently of pupil composition. However, under-control and over-control of confounding and lack of theoretical underpinning precludes definitive conclusions on how particular school characteristics influence pupils' smoking.

The influence of school culture on smoking among pupils

School factors and not solely pupil composition probably cause variation in smoking prevalence amongst schools, but there are no theoretical models to explain why. In this paper we propose a hypothesis to explain schools' influence on pupils' smoking and test this using an existing cross-sectional survey of 23,282 pupils from 166 secondary schools in the West Midlands, UK. We hypothesise that school-level educational achievement scores would not be associated with smoking prevalence, but schools providing value-added education given the social background of pupils (authoritative schools) would provide effective support and control, have a relatively strong influence on pupils' lives and be associated with lower than average smoking prevalence. Schools providing value-denuded education (laissez-faire schools) would have a relatively weak influence on pupils' lives and be associated with higher than average smoking prevalence. The school achievement measures were the proportion of pupils achieving 5A-C General Certificates of Secondary Education (5A-Cs) grades and the proportion of half days lost to truancy. Value-added/denuded terms were created by regressing 5A-Cs and truancy on five markers of the social profile of pupils at the school. Authoritative schools achieved better than expected rates on both measures. Laissez-faire schools achieved worse than expected rates on both measures. All other schools were classed as indeterminate. Multilevel logistic regression was used to relate the risk of regular smoking to school culture in both achievement and authoritative/laissez-faire terms, both with and without adjustment for pupil-level risk factors for smoking. As predicted, schools' achievement measures were unrelated to pupils' smoking. The odds ratios (95% confidence intervals) for smoking in authoritative and laissez-faire schools relative to indeterminate schools were 0.80 (0.70-0.91) and 1.16 (1.07-1.27), respectively. Adjustment for pupil-level smoking risk factors had little effect. School culture is an independent risk factor for adolescent smoking. Schools providing effective support and control might protect pupils from smoking.

Social deprivation and breast cancer

BACKGROUND

This cross-sectional study was carried out in a population-based setting in Worcestershire to investigate the relationship between social deprivation and other potential prognostic factors.

METHODS

A total of 762 female patients diagnosed with primary breast cancer between 1 January 1998 and 31 December 1999 were selected. Breast cancer included all new cases of primary invasive breast cancer and ductal carcinoma in situ. A total of 753 patients were matched by their postcode of residence to enumeration district Townsend score and then divided into three groups based on Townsend quintiles (affluent n = 478; middle n = 157; deprived n = 118). Main outcome measures were relationships between social deprivation and tumour type, stage at presentation, oestrogen receptor status, tumour grade and treatment type.

RESULTS

Compared with the most deprived women, affluent women were less likely to present with invasive ductal tumours (70.8 per cent versus 85.9 per cent, chi2 linear trend = 6.757, p = 0.009), tumours of higher grade (36.0 per cent versus 44.7 per cent, chi2 linear trend = 4.201, p = 0.040), and oestrogen receptor negative tumours (22.4 per cent versus 33.3 per cent, chi2 linear trend = 3.501, p = 0.061). There was no significant difference in stage or tumour size at presentation between deprivation groups. More deprived women with invasive tumours of less than 20 mm maximum diameter were significantly more likely to have mastectomies than affluent women (47.8 per cent versus 32.1 per cent, chi2 linear trend = 4.091, p = 0.043).

CONCLUSIONS

This study suggests that level of social deprivation is associated with tumour type, grade and oestrogen receptor status. There was also a suggestion that increased level of deprivation was associated with increased risk of potentially unnecessary mastectomies.

A cluster randomised controlled trial of smoking cessation in pregnant women comparing interventions based on the transtheoretical (stages of change) model to standard care

OBJECTIVES

To evaluate the effectiveness in helping pregnant women stop smoking of two interventions (Pro-Change for a healthy pregnancy) based on the transtheoretical model of behaviour change (TTM) compared to current standard care.

DESIGN

Cluster randomised trial.

SETTING

Antenatal clinics in West Midlands, UK general practices.

PARTICIPANTS

918 pregnant smokers

INTERVENTIONS

100 general practices were randomised into the three trial arms. Midwives in these practices delivered three interventions: A (standard care), B (TTM based self help manuals), and C (TTM based self help manuals plus sessions with an interactive computer program giving individualised smoking cessation advice).

MAIN OUTCOME MEASURES

Biochemically confirmed smoking cessation for 10 weeks previously, and point prevalence abstinence, both measured at 30 weeks of pregnancy and 10 days after delivery.

RESULTS

There were small differences between the TTM arms. Combining the two arms, the odds ratios at 30 weeks were 2.09 (95% confidence interval (CI) 0.90 to 4.85) for 10 week sustained abstinence and 2.92 (95% CI 1.42 to 6.03) for point prevalence abstinence relative to controls. At 10 days after delivery, the odds ratios were 2.81 (95% CI 1.11 to 7.13) and 1.85 (95% CI 1.00 to 3.41) for 10 week and point prevalence abstinence respectively.

CONCLUSIONS

While there is a small borderline significant increase in quitting in the combined intervention arms compared with the controls, the effect of the intervention is small. At 30 weeks gestation and at 10 days postnatal, only about 3% of the intervention groups achieved sustained cessation, with numbers needed to treat of 67 (30 weeks of gestation) and 53 (10 weeks postnatal) for one additional woman to achieve sustained confirmed cessation. Given also that the intervention was resource intensive, it is of doubtful benefit.

The importance of social sources of cigarettes to school students

OBJECTIVE

To discover the importance of social sources of tobacco to young people as opposed to commercial sources; to describe the peer market for cigarettes in schools and the consequences for young people of their involvement in it.

STUDY DESIGN

Cross sectional questionnaire survey, one-to-one interviews, and focus groups.

SETTING

Seven schools in Birmingham, UK.

SUBJECTS

All students in two randomly selected classes from each school completed the questionnaire, and never smokers, occasional smokers, and regular smokers were interviewed.

RESULTS

Two thirds of occasional smokers and one quarter of regular smokers obtained cigarettes socially, mostly for free. A few smokers regularly bought their cigarettes from others. Among friendship groups, both smokers and non-smokers were involved in the exchange of cigarettes, often for money, which is a common activity. A few young people use the selling of cigarettes to fund their own smoking. Some young people, smokers and non-smokers, are involved in semi-commercial selling of cigarettes. All school students are aware of where to purchase cigarettes from non-friends, which is only used "in emergency" because of the high price. One school had a strong punishment policy for students caught with cigarettes. In this school, more people bought singles from the peer market and the price was higher.

CONCLUSIONS

The passing and selling of cigarettes in school is a common activity, which from the young persons perspective, ensures that all share cross counter purchases. A few people are prepared to use the peer market for monetary gain and it appears to be responsive to external conditions. The peer market might mean that efforts to control illegal sales of cigarettes are not as effective as hoped.

A controlled trial of an expert system and self-help manual intervention based on the stages of change versus standard self-help materials in smoking cessation

AIM

To examine the population impact and effectiveness of the Pro-Change smoking cessation course based on the Transtheoretical Model (TTM) compared to standard self-help smoking cessation literature.

DESIGN

Randomized controlled trial.

SETTING

Sixty-five West Midlands general practices.

PARTICIPANTS

Randomly sampled patients recorded as smokers by their general practitioners received an invitation letter and 2471 current smokers agreed.

INTERVENTIONS

Responders were randomized to one of four interventions. The control group received standard self-help literature. In the Manual intervention group, participants received the Pro-Change system, a self-help workbook and three questionnaires at 3-monthly intervals, which generated individually tailored feedback. In the Phone intervention group, participants received the Manual intervention plus three telephone calls. In the Nurse intervention group, participants received the Manual intervention plus three visits to the practice nurse.

MEASUREMENTS

Biochemically confirmed point prevalence of being quit and 6-month sustained abstinence, 12 months after study commencement.

FINDINGS

A total of 9.1% of registered current smokers participated, of whom 83.0% were not ready to quit. Less than half of participants returned questionnaires to generate second and third individualized feedback. Telephone calls reached 75% of those scheduled, but few participants visited the nurse. There were small differences between the three Pro-Change arms. The odds ratio (95% confidence intervals) for all Pro-Change arms combined versus the control arm were 1.50 (0.85-2.67) and 1.53 (0.76-3.10), for point prevalence and 6-month abstinence, respectively. This constitutes 2.1% of the TTM group versus 1.4% of the control group achieving confirmed 6-month sustained abstinence.

CONCLUSIONS

There was no statistically significant benefit of the intervention apparent in this trial and the high relapse of quitters means that any population impact is small.

The risk of smoking in relation to engagement with a school-based smoking intervention

Health promotion interventions cannot work if people do not engage with them. The aim of this study was to examine whether disengagement from an adolescent smoking prevention and cessation intervention was an independent risk factor for regular smoking 1 and 2 years later. The data were taken from a cluster randomised controlled trial, in the West Midlands, UK, based on the transtheoretical or stages of change model. In this trial, 8,352 13-14-year old school pupils enrolled, and the data in this report were based on the 7,413 and 6,782 pupils present at 1 and 2 years follow-ups, respectively. The intervention group undertook three sessions using an interactive computer programme. At the end of the programme, pupils recorded their responses to it. Pupils were classed as engaged if they thought the intervention was both useful and interesting; all others were classed as disengaged. Random effects logistic regression related the number of times engaged to regular smoking at 1 and 2 years follow-up, adjusted for school absences and 11 potential confounders. The majority of pupils were engaged by the intervention. For participants using the intervention three times but not engaging once, the odds ratios (95% confidence intervals) for smoking at 1 and 2 years relative to the controls were 1.83 (1.41-2.39) and 1.70 (1.38-2.11). For those engaging three times, they were 0.79 (0.60-1.03) and 0.96 (0.75-1.21). There was no interaction with baseline intention to smoke, classified by stage of change, but there was a borderline significant interaction with baseline smoking status, with disengagement acting as a stronger risk factor among baseline never-smokers. We conclude that disengagement from interventions is a risk factor for smoking independently of experimentation with cigarettes. The best explanation is that disengagement from school, an established risk factor for smoking, generalises to disengagement from didactic school-based health promotion programmes.

Exposure to power frequency electric fields and the risk of childhood cancer in the UK

The United Kingdom Childhood Cancer Study, a population-based case-control study covering the whole of Great Britain, incorporated a pilot study measuring electric fields. Measurements were made in the homes of 473 children who were diagnosed with a malignant neoplasm between 1992 and 1996 and who were aged 0-14 at diagnosis, together with 453 controls matched on age, sex and geographical location. Exposure assessments comprised resultant spot measurements in the child's bedroom and the family living-room. Temporal stability of bedroom fields was investigated through continuous logging of the 48-h vertical component at the child's bedside supported by repeat spot measurements. The principal exposure metric used was the mean of the pillow and bed centre measurements. For the 273 cases and 276 controls with fully validated measures, comparing those with a measured electric field exposure >/=20 V m(-1) to those in a reference category of exposure <10 V m(-1), odds ratios of 1.31 (95% confidence interval 0.68-2.54) for acute lymphoblastic leukaemia, 1.32 (95% confidence interval 0.73-2.39) for total leukaemia, 2.12 (95% confidence interval 0.78-5.78) for central nervous system cancers and 1.26 (95% confidence interval 0.77-2.07) for all malignancies were obtained. When considering the 426 cases and 419 controls with no invalid measures, the corresponding odds ratios were 0.86 (95% confidence interval 0.49-1.51) for acute lymphoblastic leukaemia, 0.93 (95% confidence interval 0.56-1.54) for total leukaemia, 1.43 (95% confidence interval 0.68-3.02) for central nervous system cancers and 0.90 (95% confidence interval 0.59-1.35) for all malignancies. With exposure modelled as a continuous variable, odds ratios for an increase in the principal metric of 10 V m(-1) were close to unity for all disease categories, never differing significantly from one.

Can the stages of change for smoking acquisition be measured reliably in adolescents?

BACKGROUND

was to examine the reliability of the algorithm.

METHODS

As part of a randomized controlled trial, 3,930 adolescents completed a paper version of the algorithm questions and a differently worded computerized version on the same day: a parallel form reliability assessment. In a separate assessment, another group of 118 adolescents completed 2 identical paper versions of the same questionnaire 2 weeks apart: a test-retest reliability assessment. Kappa (kappa) for agreement for stage and the individual questions were calculated. Logistic regression was used to examine whether demographic characteristics, smoking status, and stage predicted agreement for stage.

RESULTS

Kappa (95% confidence intervals) for stage was 0.57 (0.55-0.60) in the first assessment and 0.46 (0.28-0.63) in the second assessment, indicating moderate reliability. The question concerning trying smoking in the next 6 months was moderately reliable, but that concerning trying within the next thirty days was poorly reliable. Acquisition precontemplation was significantly more reliably coded than all other stages. Demographic characteristics did not predict reliability.

CONCLUSIONS

The algorithm reliably allocates individuals into acquisition precontemplation, but for all other stages, its reliability is fair.