Passive smoking and lung cancer: a publication bias?

To assess the likelihood of publication bias in a recent review of the effect of passive smoking on lung cancer the evidence from the reviewed papers was visualised on a "funnel" plot. In such a plot if the relative risks from various studies are plotted according to sample size they should scatter round some underlying true value, the scatter being greatest where the studies have the lowest statistical power--thus showing a "funnel" pattern. If there is publication bias and studies with non-significant results are not being published there should be a "gap" in the plot. The logarithm of the relative risks was plotted against the standard error of the logarithm of the relative risk (which was used instead of sample size as a measure of statistical uncertainty). The resulting plot was compatible with a publication bias but only in studies on men. Further studies of passive smoking and lung cancer in men seem to be warranted.     

β-carotene protects rats against bronchitis induced by cigarette smoking

Objective To investigate the protective effects of B-carotene in rats against the development of chronic bronchitis induced by cigarette smoking.Methods Forty-two Male Wistar rats were randomly divided into three study groups: ①control (n =15), animals underwent no treatment; ②cigarette smoking (n = 15), animals developed chronic bronchitis through long-term cigarette smoking twice a day for 75 d; ③β-carotene plus cigarette smoking animals (n =12) were given 1 ml or 15 mg/kg β-carotene orally every day just before cigarette smoking. The levels of IL-6, IL-8, NO, superoxide dismutase (SOD) and lipoperoxide(LPO) in serum, bronchoalveolar lavage fluid (BALF) and lung tissue were measured and the pathological changes to lung tissue were analyzed using light microscopy.Fiesults Long-term cigarette smoking caused an obvious increase in the amount of IL-6, IL-8 and LPO and a sharp decrease in the levels of NO and SOD in smoking animals compared to controls. β-carotene intake reversed all the changes induced by smoking and alleviated the pathological changes caused by chronic bronchitis.Conclusions Quantitative oral intake of B-carotene had protective effects against chronic bronchitis induced by long-term cigarette smoking, which was associated with the increased production of NO,the clearance of some oxidative free radicals (OFR) and the alleviation of chronic inflammation.     

Nicotine conjugate vaccine: is there a right to a smoking future?

Tobacco consumption is believed to be one of the world's greatest preventable health problems. According to the World Health Organisation, 1.1 billion people worldwide are addicted to nicotine with tobacco causing an estimated four million premature deaths every year. The development of a nicotine conjugate vaccine suggests that immunisation may hold promise as a future therapeutic and preventive strategy for tobacco smoking and nicotine addiction. Allowing parents to immunise their children against smoking could be an infringement of children's right to an open future, however, and is not ethically unproblematic     

ESR spin trapping studies on the free radicals in gasphase of cigarette smoking.

Free radicals in the gasphase of cigarette smoke were determined by spin trapping agent PBN (N-tert-butyl-2-phenyl nitrone) and DMPO (5,5-dimethyl-1-pyrroline-oxide) on electron spin resonance spectrometer. They were identified according to the spectrum parameters calculated from the spectra. The free radicals mainly consist of alkoxyl and alkyl free radicals, of which alkoxyl free radicals make up 60-70% of the total spectral components. These free radicals are very active and reactive. They can damage cells and lead to some diseases. This work points out the importance of scavenging the free radicals of cigarette smoke to prevent diseases caused by them.

     

Circulatory crisis caused by cigarette smoking in tissue transfer. Clinical and experimental studies.

Cigarette smoking-induced circulatory crisis occurred in two patients receiving toe transfer and one patient having musculocutaneous flap. After anticoagulation and antispasm treatment, one survived and two failed. Experimental studies demonstrated that cigarette smoking is harmful to the healing of endothelia at the anastomotic site of vessels. Five days after operation, the complete recovery rate of the endothelium over sutures of anastomotic sites was 16%-19% in smoking groups, but 75% in the control group. The mechanism and characteristics of circulatory crisis caused by cigarette smoking are discussed.

     

Inhibition of tumor necrosis factor-α reduces alveolar septal cell apoptosis in passive smoking rats

Background Recent studies have revealed that lung cell apoptosis plays an important role in pathogenesis of cigarette-induced chronic obstructive pulmonary disease （COPD）. Tumor necrosis factor alpha （TNF-α） is one of the most important cytokines which are involved in COPD. This study aimed at investigating the influence of its inhibitor, recombinant human necrosis factor-alpha receptor II：lgG Fc fusion protein （rhTNFR：Fc） on alveolar septal cell apoptosis in passive smoking rats. Methods Forty-eight rats were randomly divided into a normal control group, a passive smoking group, an rhTNFR：Fc intervention group and a sham intervention group. The passive smoking rats were treated by exposure to cigarette smoking daily for 80 days. After smoking for one month the rhTNFR：Fc intervention group was treated with rhTNFR：Fc by subcutaneous injection, the sham intervention group injected subcutaneously with a neutral preparation （normal saline 0.1 ml, manicol 0.8 ml, cane sugar 0.2 mg, Tris 0.024 mg as a control. Lung function was determined and the levels of TNF-a in serum and broncho-alveolar lavage fluid （BALF） were measured with enzyme-linked immunosorbnent assay （ELISA）. Lung tissue sections stained by hematoxylin and eosin （HE） were observed for study of morphological alternations. Mean linear intercept （MLI） and mean alveolar numbers （MAN） were measured and the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling （TUNEL） method was carried out to determine the percentage of positive cells and distribution of apoptotic cells. Results Increased MLI and decreased MAN were found in the passive smoking group compared with both the normal control group and the rhTNFR：Fc intervention group （P〈0.05）. Forced expiratory volume in 0.3 second （FEVo.3）/forced vital capacity （FVC） and peak expiratory flow （PEF） were lower in the passive smoking group than that in the normal control group （P〈0.05）. Compared with the sham intervention group     

Methods used to quit smoking in the United States. Do cessation programs help?

Using data from the 1986 Adult Use of Tobacco Survey, we analyzed smoking-cessation methods used by adult smokers in the United States who tried to quit. About 90% of successful quitters and 80% of unsuccessful quitters used individual methods of smoking cessation rather than organized programs. Most of these smokers who quit on their own used a "cold turkey" approach. Multivariate analysis showed that women, middle-aged persons, more educated persons, persons who had made more quit-smoking attempts, and, particularly, heavier smokers were most likely to use a cessation program. Daily cigarette consumption, however, did not predict whether persons would succeed or fail during their attempts to quit smoking. Rather, the cessation method used was the strongest predictor of success. Among smokers who had attempted cessation within the previous 10 years, 47.5% of persons who tried to quit on their own were successful whereas only 23.6% of persons who used cessation programs succeeded. We conclude that cessation programs serve a small, but important, population of smokers that includes heavier smokers, those most at risk for tobacco-related morbidity and mortality.     

Genetic variants in three genes and smoking show strong associations with susceptibility to exudative age-related macular degeneration in a Chinese population

Background The present study was undertaken to replicate the associations of representative polymorphisms in three genes （complement factor H （CFH）, complement factor B （BF） and HtrA serine peptidase 1 （HTRA1）） with exudative age-related macular degeneration （AMD） in a Han Chinese population, and to test if the modifiable environmental factors affect AMD susceptibility associated with different type of genotype in these genes. Methods An age, gender and ethnicity matched case-control study was conducted to genotype the representative single neucleotide polymorphisms （SNPs） loci including rs1061170 and rs1410996 in CFH, rs641153 and rs4151667 in BF and rs11200638 in HTRA1 gene in 144 exudative AMD patients and 126 normal controls using PCR-RFLP and direct resequencing. The demographic characteristics and behavioral risk factors were also recorded. Allelic and genotypic associations for individual SNP and joint associations with two loci were performed. The gene-gene and gene-environment interactions were analyzed using multivariate non-conditional Logistic regression analysis. Results The C risk allele frequencies for CFH Y402H （rs1061170） in cases and controls were 12.5% and 5.4% respectively, which were much lower than those in Caucasians （P 〈0.001）. Compared with TT homozygous genotype, the CT heterozygous genotype was positively associated with AMD with odds ratio （OR） of 3.23 （1.36-5.07）. However, the population attributable risk （PAR） of C allele was only 3.3% （1.4%-4.3%）. rs1410996 was also associated with AMD independent of Y402H. The ORs of exudative AMD for individuals carrying one copy risk allele and two copy risk alleles were 2.57 （1.21-5.45） and 4.76 （2.15-10.55） respectively, with correspondent PARs of 28.3% （2.0%-40.5%） and 38.2% （21.8%-45.4%）. rs11200636 in HTRA1 was another susceptible locus for AMD and the risk homozygotes were significantly susceptible for exudutive AMD （OR=3.98, 1.88-8.43） with PAR of 38.9% （24.3%-45.8%）     

Has the ban on smoking in New South Wales restaurants worked? A comparison of restaurants in Sydney and Melbourne.

OBJECTIVE: To evaluate compliance with a legislative ban on smoking inside restaurants by comparing smoking in Sydney restaurants (where it is legally banned) with smoking in Melbourne restaurants (not subject to a legal ban). DESIGN AND PARTICIPANTS: Unobtrusive observational study of restaurant patrons, and interviews with restaurant staff, carried out by 159 volunteers. SETTING: 78 Sydney restaurants with smoke-free indoor environments (as required by legislation) and 81 Melbourne restaurants not subject to legislation preventing smoking. The study took place from 20-31 October 2000. INTERVENTION: Legislation to ban smoking in indoor areas of restaurants was introduced in New South Wales in September 2000 (about six weeks before our study). OUTCOMES: Observed incidents of smoking inside restaurants; staff attitudes to the ban; customer satisfaction as indicated by comments to staff; staff perceptions of restaurant patronage. RESULTS: No restaurant patrons were seen smoking in 78 Sydney restaurants during 156 hours of observation of 2,646 diners, compared with 176 smokers among 3,014 Melbourne diners over 154 hours of observation. Thirty-one per cent (24/78) of Sydney restaurants had experienced smokers attempting to smoke indoors after the legislation was introduced; 6% (5/78) reported instances of smokers refusing to stop smoking when asked; 79% (62/78) of restaurants had received favourable comments from patrons about the smoke-free law; 81% (63/78) of restaurant staff interviewed either supported or strongly supported the law. Since introduction of the legislation, 76% of restaurants reported normal trade, 14% increased trade, and 9% reduced trade. CONCLUSIONS: Smoke-free restaurants do not require "smoking police" to enforce bans, present few ongoing difficulties for staff, attract many more favourable than unfavourable comments from patrons, and do not adversely affect trade.     

Is telephone counselling a useful addition to physician advice and nicotine replacement therapy in helping patients to stop smoking? A randomized controlled trial

BACKGROUND: The authors evaluated the incremental efficacy of telephone counselling by a nurse in addition to physician advice and nicotine replacement therapy in helping patients to stop smoking. METHODS: The trial was conducted at the University of Ottawa Heart Institute. A total of 396 volunteers who smoked 15 or more cigarettes daily were randomly assigned to either of 2 groups: usual care (control group) and usual care plus telephone counselling (intervention group); the groups were stratified by sex and degree of nicotine dependence. Usual care involved the receipt of physician advice on 3 occasions, self-help materials and 12 weeks of nicotine replacement therapy. Telephone counselling was provided by a nurse at 2, 6 and 13 weeks after the target quit date. Point-prevalent quit rates were determined at 52 weeks after the target quit date. RESULTS: The point-prevalent quit rates at 52 weeks did not differ significantly between the control and intervention groups (24.1% v. 23.4% respectively). The quit rates did not differ significantly at the secondary measurement points of 4, 12 and 26 weeks. INTERPRETATION: Brief physician assistance, along with nicotine replacement therapy, can help well-motivated smokers to quit. Three additional sessions of telephone counselling by a nurse were ineffective in increasing quit rates. This form of assistance may be useful in the absence of physician advice or when self-selected by patients.     

Which sociodemographic factors are important on smoking behaviour of high school students? The contribution of classification and regression tree methodology in a broad epidemiological survey

Background

The purpose of this study is to evaluate the most important sociodemographic factors on smoking status of high school students using a broad randomised epidemiological survey.

Methods

Using in‐class, self administered questionnaire about their sociodemographic variables and smoking behaviour, a representative sample of total 3304 students of preparatory, 9th, 10th, and 11th grades, from 22 randomly selected schools of Mersin, were evaluated and discriminative factors have been determined using appropriate statistics. In addition to binary logistic regression analysis, the study evaluated combined effects of these factors using classification and regression tree methodology, as a new statistical method.

Results

The data showed that 38% of the students reported lifetime smoking and 16.9% of them reported current smoking with a male predominancy and increasing prevalence by age. Second hand smoking was reported at a 74.3% frequency with father predominance (56.6%). The significantly important factors that affect current smoking in these age groups were increased by household size, late birth rank, certain school types, low academic performance, increased second hand smoking, and stress (especially reported as separation from a close friend or because of violence at home). Classification and regression tree methodology showed the importance of some neglected sociodemographic factors with a good classification capacity.

Conclusions

It was concluded that, as closely related with sociocultural factors, smoking was a common problem in this young population, generating important academic and social burden in youth life and with increasing data about this behaviour and using new statistical methods, effective coping strategies could be composed.