Weight growth in infants born to mothers who smoked during pregnancy.

OBJECTIVE--To determine whether maternal smoking during pregnancy causes impairment in growth after birth. DESIGN--Longitudinal study. SETTING--Six medical university centres of six towns of north, central, and south Italy. SUBJECTS--12,987 babies (10,238 born from non-smoking mothers, 2276 from mothers smoking one to nine cigarettes a day, and 473 from mothers smoking > or = 10 cigarettes a day) entered the study. MAIN OUTCOME MEASURES--Difference in weight gain between children born to smoking mothers and those born to non-smoking mothers. Weight was measured at birth and at 3 and 6 months of age. Maternal smoking habit was derived from interview on third or fourth day after delivery. RESULTS--Compared with children born to mothers who did not smoke during pregnancy, the birth weights of children born to mothers who smoked up to nine cigarettes a day were 88 g (girls) and 107 g (boys) lower; in children born to mothers who smoked > or = 10 cigarettes a day weights were 168 g and 247 g lower. At six months of age for the first group the mean weight for girls was 9 g (95% confidence interval -47 g to 65 g) higher and for boys 64 g (-118 g to -10 g) lower than that of children born to mothers who did not smoke. The corresponding figures for the second group were 28 g (-141 g to 85 g) lower for girls and 24 g (-136 g to 88 g) lower for boys. CONCLUSIONS--The deficits of weight at birth in children born to mothers who smoked during pregnancy are overcome by 6 months of age. These deficits are probably not permanent when smoking habit during pregnancy is not associated with other unfavourable variables (such as lower socioeconomic class).     

Cigarette advertising and onset of smoking in children: questionnaire survey.

OBJECTIVE: To investigate uptake of smoking in a cohort of 11 to 12 year olds related to awareness of advertised cigarette brands named. DESIGN: Self completed questionnaires administered to whole classes of schoolchildren in June 1993 and June 1994. SETTING: Primary, middle, and secondary schools in the north and south of England. SUBJECTS: 1450 pupils aged 11 and 12 years at the time of the first survey. MAIN OUTCOME MEASURES: Onset of smoking and brands smoked by the second survey related to cigarette brands named in the first one. Less advertised brands were used as the base for calculating odds ratios. RESULTS: Girls who named the most advertised brands-namely, Benson and Hedges alone (odds ratio = 2.50, 95% confidence interval = 1.18 to 5.30) or Benson and Hedges and Silk Cut (2.15, 1.04 to 4.42) in the first survey were at greatest risk of taking up smoking by the second one. The difference was similar but not significant for boys. Boys and girls who named the least advertised brands in the first survey were at no greater risk of taking up smoking by the second survey than those who named no brands (boys odds ratio = 0.49 (0.24 to 1.01); girls 0.79 (0.38 to 1.62)). New smokers were more likely to smoke any available brand (29.5%) or a less advertised brand such as Embassy (24.6%) than the most advertised ones, Benson and Hedges (19.7%) and Silk Cut (14.8%). Established smokers were more selective, only 15% smoking any available brand and 38.3% smoking Benson and Hedges. CONCLUSIONS: Cigarette advertising appears to increase children''s awareness of smoking at a generic level and encourages them to take up the behaviour, beginning with any cigarettes which are available and affordable.     

Effects of age, ethnicity and health behaviours on the prevalence of adverse birth outcomes in Taiwan

This study sampled 8432 singleton first live births from Taiwan's 2005 Birth Registration Database to determine if there were more pre-term or low birth weight deliveries among aboriginal women than there were among Han Chinese women, and if the 'weathering' hypothesis applied to aboriginal women in Taiwan. Although the aboriginal women were socially disadvantaged and engaged in more unhealthy behaviours, including smoking, drinking, chewing betel quid and exposure to second-hand smoke, the evidence did not support the hypothesis that these teenaged minority women would have better birth outcomes, as has been demonstrated among teenage African-American women in the United States. Behaviours and not ethnicity were risk factors for teenage aboriginal mothers, who started deleterious health behaviours earlier than did their older counterparts. Teenage mothers had more adverse outcomes regardless of ethnicity and aboriginal mothers had more risky behaviours in all age groups. The prevalence of detrimental health behaviour among teenage mothers in Taiwan is of concern, particularly for aboriginal teenage mothers.     

Study of smoking habits in hospital and attitudes of medical staff towards smoking.

Most hospital policies place little or no restriction on patients'' smoking in hospital. In this study patients were surveyed to determine if they smoked and if their doctors advised or ordered them to stop smoking in hospital. As well, the smoking habits and attitudes towards smoking of the medical staff and other hospital workers were explored. Of 741 patients 37% were smokers, and those who responded fully to a questionnaire 86% continued to smoke in hospital. Patients who were advised or ordered not to smoke (59%) were no more likely to stop smoking than those who were not so advised or ordered. Physicians were less likely to smoke than other hospital staff, and those who did smoke were much more likely not to smoke while in the hospital. Physicians appear to have a reasonable appreciation of the health hazards of smoking, and almost two thirds are in favour of stricter restrictions on patients'' smoking in hospital. The ineffectiveness of their efforts is primarily due to hospital policies that are not in keeping with physicians'' standards of practice and with established knowledge of the deleterious effects of smoking on health.     

Orofacial clefts, parental cigarette smoking, and transforming growth factor-alpha gene variants.

Results of studies to determine whether women who smoke during early pregnancy are at increased risk of delivering infants with orofacial clefts have been mixed, and recently a gene-environment interaction between maternal smoking, transforming growth factor-alpha (TGFa), and clefting has been reported. Using a large population-based case-control study, we investigated whether parental periconceptional cigarette smoking was associated with an increased risk for having offspring with orofacial clefts. We also investigated the influence of genetic variation of the TGFa locus on the relation between smoking and clefting. Parental smoking information was obtained from telephone interviews with mothers of 731 (84.7% of eligible) orofacial cleft case infants and with mothers of 734 (78.2%) nonmalformed control infants. DNA was obtained from newborn screening blood spots and genotyped for the allelic variants of TGFa. We found that risks associated with maternal smoking were most elevated for isolated cleft lip with or without cleft palate, (odds ratio 2.1 [95% confidence interval 1.3-3.6]) and for isolated cleft palate (odds ratio 2.2 [1.1-4.5]) when mothers smoked > or =20 cigarettes/d. Analyses controlling for the potential influence of other variables did not reveal substantially different results. Clefting risks were even greater for infants with the TGFa allele previously associated with clefting whose mothers smoked > or =20 cigarettes/d. These risks for white infants ranged from 3-fold to 11-fold across phenotypic groups. Paternal smoking was not associated with clefting among the offspring of nonsmoking mothers, and passive smoke exposures were associated with at most slightly increased risks. This study offers evidence that the risk for orofacial clefting in infants may be influenced by maternal smoke exposures alone as well as in combination (gene-environment interaction) with the presence of the uncommon TGFa allele.     

Early sexual intercourse and risk factors in Croatian adolescents

Sexual behaviour in adolescence is a sensitive issue and has possible immediate and long term medical and psychical consequences. The aim of the study was to examine whether early sexual intercourse varies by gender and how is associated with unhealthy behaviour and factors of psycho-social well-being. 773 boys and 857 girls of 15.5 years old, included in a representative national school-based survey, conducted in Croatia in 2006, were invited to fill in anonymous questionnaires. Sexual experience before the age of 16 years was reported by 28.6% of the boys and 16.5% of the girls. Early sexual experience in boys was associated with smoking, drinking of alcohol, marijuana taking, physical fighting, and bullying other The odds ratio was highest for smoking. (OR:8. 1; CI:5.4-12. 1). For girls the same variables were associated with the early sexual intercourse, marijuana use being the strongest independent predictor (OR:8.0; CI:5.0-12.6). While controlled for other behaviours, daily smoking remained the strongest predictor for both genders. Girls who had early sexual experience were more prone to be dissatisfied with their health (OR:2.9; CI:2.0-4.2), with their life (OR:2.1; CI:1.4-3.0), communication with father and mother (OR:1.9; CI:1.2-2.8 and OR:1. 7; CI:1.1-2.6) and reported more psychosomatic symptoms (OR:2.9; CI:2.0-4.3). For both genders odds were higher if they had good communication with the friend of the opposite gender. Evenings spent out with friends were associated to early sexual experience in boys and girls as well as poorer school achievement. Early menarche was associated with the probability of being engaged in the early sexual intercourse and with smoking, marijuana use and psychosomatic symptoms. Early sexual intercourse is associated with unhealthy behaviour such as smoking, substance abuse, aggressiveness and lower psychosocial well-being. Preventive educational programmes should follow multi-facet approaches and recognize differences between boys and girls. Human papillomavirus (HPV) vaccination could be part of a comprehensive approach and is not to be viewed as an isolated activity.     

Cotinine levels and self-reported smoking status in patients attending a bronchoscopy clinic.

The reliability of self-reported smoking behaviour can vary and may result in bias if errors in misclassification vary with outcome. We examined whether self-report was an accurate measure of current smoking status in patients with malignant or non-malignant respiratory disease. Smoking behaviour was assessed by self-report and by analysis of whole blood for cotinine, a biomarker of exposure to cigarette smoke, in 166 patients attending a bronchoscopy clinic. Cotinine levels ranged from 2.5 to >400 ng ml(-1) blood and were higher in self-reported current smokers (173+/-123 ng ml(-1)) than in never smokers (3.7+/-8.7 ng ml(-1)) or ex-smokers (20.5+/-49.0 ng ml(-1)). Cotinine levels in self-reported current smokers increased with the numbers of cigarettes smoked (p=0.06), and levels in smokers and ex-smokers decreased with the reported length of time since the last cigarette (p=0.001). Using a cotinine level of 20 ng ml(-1) and self-report as the gold standard, the sensitivity and specificity for defining current smoking status were 90.2% and 82.4%, respectively. Out of a total of 125 self-reported current non-smokers, 23 (18.4%) had cotinine levels greater than 20 ng ml(-1). Smoking prevalence was significantly underestimated by self-report (24.7%) when compared with that defined using blood cotinine levels (36.1%: p<0.001). Misclassification of current smoking status was particularly high in ex-smokers, in patients without malignant respiratory disease, in men, and in those below the median age. Such differential misclassification may result in bias in studies examining associations between current smoking habits and disease risk.     

Excess smoking in malignant-phase hypertension

The smoking habits of 82 patients with malignant-phase hypertension were compared with those of subjects in three control groups matched for age and sex. Sixty-seven (82%) of the patients with malignant-phase hypertension were smokers compared with 41 (50%) and 71 (43%) of the patients in two control groups with non-malignant hypertension, and 43 people (52%) in a general population survey. The excess of smokers in the malignant-phase group was significant for men and women, together and separately, for cigarette smoking alone, and for all forms of smoking. There were no significant differences between the control groups. The chance of a hypertensive patient who smoked having the malignant phase was five times that of a hypertensive patient who did not. Twelve patients in the malignant-phase group had never smoked. All were alive three and a half years on average after presentation (range 11 months to seven years). Twenty-four (36%) of the smokers with malignant-phase hypertension died during the same period. The mortality rate was significantly higher among patients with renal failure, as was the prevalence of smoking. Eighteen patients with malignant-phase hypertension had a serum creatinine concentration higher than 250 μmol/l (2·8 mg/100 ml); 17 were smokers and one an ex-smoker. Eleven of these 18 patients died.It is concluded that hypertensive patients who smoke are much more likely to develop the malignant phase than those who do not, and that once the condition has developed it follows a particularly lethal course in smokers.     

Genotoxicity of environmental tobacco smoke: a review

Environmental tobacco smoke (ETS), or second-hand smoke, is a widespread contaminant of indoor air in environments where smoking is not prohibited. It is a significant source of exposure to a large number of substances known to be hazardous to human health. Numerous expert panels have concluded that there is sufficient evidence to classify involuntary smoking (or passive smoking) as carcinogenic to humans. According to the recent evaluation by the International Agency for Research on Cancer, involuntary smoking causes lung cancer in never-smokers with an excess risk in the order of 20% for women and 30% for men. The present paper reviews studies on genotoxicity and related endpoints carried out on ETS since the mid-1980s. The evidence from in vitro studies demonstrates induction of DNA strand breaks, formation of DNA adducts, mutagenicity in bacterial assays and cytogenetic effects. In vivo experiments in rodents have shown that exposure to tobacco smoke, whole-body exposure to mainstream smoke (MS), sidestream smoke (SS), or their mixture, causes DNA single strand breaks, aromatic adducts and oxidative damage to DNA, chromosome aberrations and micronuclei. Genotoxicity of transplacental exposure to ETS has also been reported. Review of human biomarker studies conducted among non-smokers with involuntary exposure to tobacco smoke indicates presence of DNA adducts, urinary metabolites of carcinogens, urinary mutagenicity, SCEs and hypoxanthine-guanine phosphoribosyltransferase (HPRT) gene mutations (in newborns exposed through involuntary smoking of the mother). Studies on human lung cancer from smokers and never-smokers involuntarily exposed to tobacco smoke suggest occurrence of similar kinds of genetic alterations in both groups. In conclusion, these overwhelming data are compatible with the current knowledge on the mechanisms of carcinogenesis of tobacco-related cancers, occurring not only in smokers but with a high biological plausibility also in involuntary smokers.     

Smoking as a weight-control strategy among adolescent girls and young women: a reconsideration

Many studies have reported that adolescent girls and young women smoke to control their weight. The majority of these studies are cross-sectional and report on correlational data from quantitative surveys. This article presents data from ethnographic interviews with 60 smokers, interviewed in high school and in follow-up interviews at age 21. Contrary to previous research, this study found little evidence for the sustained use of smoking as a weight-control strategy. In high school, smokers were no more likely than nonsmokers to be trying to lose weight. In the follow-up study, 85 percent of informants replied that they had never smoked as a way to control their weight. One-half of informants at age 21 believed that smoking as a weight-control strategy would be ineffective, while the other one-half had no idea whether it would work or not. Researchers need to exert caution in propagating the idea that smoking is commonly used as a conscious and sustained weight-control strategy among adolescent females and young women.     

HPRT gene alterations in umbilical cord blood T-lymphocytes in newborns of mothers exposed to tobacco smoke during pregnancy

Prenatal exposure to tobacco smoke has been associated with an increased risk of pediatric malignancies, yet the transplacental induction of genetic alterations by tobacco smoke carcinogens and their implication to childhood diseases remain poorly understood. We characterized mutations in the HPRT gene in umbilical cord blood T-lymphocytes of self-reported 103 never-smoking mothers and 104 smoking mothers (54 mothers smoked throughout and 50 mothers quit smoking during pregnancy). The results showed the illegitimate V(D)J recombinase-mediated deletion of HPRT exons 2-3 was the most prominent alteration occurring in 48.2% (26/54) of mutants from neonates of the smoking mothers who smoked during pregnancy, compared with 28.0% (14/50) from those of smoking mothers who quit smoking during pregnancy (p=0.035, Fisher's exact test), 34.9% (36/103) from never-smoking mothers (p=0.08), or 32.7% (50/153) of those of neonates born from the latter two groups of mothers combined (p=0.043). There was no significant difference in the frequency of this deletion between neonates of the never-smoking mothers and the smoking mothers who quit smoking during pregnancy (34.9% versus 28.0%, respectively, p=0.39). The results show an increase in illegitimate V(D)J recombinase-mediated deletion of HPRT exons 2-3 in cord blood T-lymphocytes of newborns of mothers who smoked during pregnancy, compared with the group of mothers who did not smoke during pregnancy, implying an increase in illegitimate V(D)J recombinase-mediated alteration, a genetic recombination event associated with childhood malignancies, may be induced in utero during pregnancy by maternal exposure to tobacco smoke-derived genotoxicants.     

The influence of mother's active smoking during pregnancy on body mass index of newborns

Many investigations have noted bad influence of smoking during pregnancy. In the present article, the influence of mothers smoking during pregnancy on the body mass index (BMI), birth weight and birth length are examined. This retrospective research included 219 children: Group I: 109 children from rural area of east Slavonia (born in General Hospital-Vinkovci) and group II: 110 children from industrial area (born in Zagreb). The questioned subjects were divided into two groups depending on mothers smoking during pregnancy: newborns of mothers who didn't smoke during pregnancy (subgroup A) and newborns of mother who did smoke 10 or more cigarettes per day during pregnancy (subgroup B). Anthropometric parameters (BMI, birth length and birth weight) in newborns of non-smoking mothers were statistically higher (p < 0.05) than in newborns of smoking mothers. Moderate correlation between birth length and birth weight in newborns of non-smoking and smoking mothers from rural area and from non-smoking mothers in urban area was statistically significant, but correlation in the group in newborns of smoking mothers from Zagreb was not statistically significant. Results of this research show that smoking during pregnancy significantly influences the birth weight and birth length. Further investigation is needed, to investigate the lack of correlation between the birth length and birth weight in newborns of smoking mothers from industrial city.     

Nortriptyline plus nicotine replacement versus placebo plus nicotine replacement for smoking cessation: pragmatic randomised controlled trial

Objective To test the efficacy of nortriptyline plus nicotine replacement therapy compared with placebo plus nicotine replacement therapy for smoking cessation.Design Pragmatic randomised controlled trial.Setting National Health Service stop smoking service clinics.Participants 901 people trying to stop smoking.Interventions Participants chose their nicotine replacement product, including combinations of nicotine replacement therapy, and received behavioural support. Nortriptyline was started one to two weeks before quit day, with the dose increased from 25 mg to 75 mg daily for eight weeks and reduced if not tolerated.Main outcome measures Primary outcome was prolonged confirmed abstinence at six months. Secondary outcomes were prolonged abstinence at 12 months, drug use, severity of side effects, nicotine withdrawal symptoms, and urges to smoke.Results 72 of 445 (16%) people using nortriptyline and 55 of 456 (12%) using placebo achieved prolonged abstinence at six months (relative risk 1.34, 95% confidence interval 0.97 to 1.86). At 12 months the corresponding values were 49 (11%) for nortriptyline and 40 (9%) for placebo (1.26, 0.84 to 1.87). 337 (79%) people in the nortriptyline arm and 325 (75%) in the placebo arm were taking combination treatment on quit day, median 75 mg per day in both groups. More people in the nortriptyline arm than in the placebo arm took lower doses. The nortriptyline arm had noticeably higher severity ratings for dry mouth and constipation than the placebo arm, with slightly higher ratings for sweating and feeling shaky. Both groups had similar urges to smoke, but nortriptyline reduced depression and anxiety. Overall, withdrawal symptom scores did not differ.Conclusions Nortriptyline and nicotine replacement therapy are both effective for smoking cessation but the effect of the combination is less than either alone and evidence is lacking that combination treatment is more effective than either alone.Trial registration Current Controlled Trials ISRCTN57852484.     

What helps and hinders midwives in engaging with pregnant women about stopping smoking? A cross-sectional survey of perceived implementation difficulties among midwives in the North East of England

ABSTRACT: BACKGROUND: Around 5,000 miscarriages and 300 perinatal deaths per year result from maternal smoking in the United Kingdom. In the northeast of England, 22% of women smoke at delivery compared to 14% nationally. Midwives have designated responsibilities to help pregnant women stop smoking. We aimed to assess perceived implementation difficulties regarding midwives' roles in smoking cessation in pregnancy. METHODS: A self-completed, anonymous survey was sent to all midwives in northeast England (n?=?1,358) that explores the theoretical explanations for implementation difficulties of four behaviours recommended in the National Institute for Health and Clinical Excellence (NICE) guidance: (a) asking a pregnant woman about her smoking behaviour, (b) referring to the stop-smoking service, (c) giving advice about smoking behaviour, and (d) using a carbon monoxide monitor. Questions covering Michie et al.'s theoretical domain framework (TDF), describing 11 domains of hypothesised behavioural determinants (i.e., 'knowledge', 'skills', 'social/professional role/identity', 'beliefs about capabilities', 'beliefs about consequences', 'motivation and goals', 'memory', 'attention and decision processes', 'environmental context and resources', 'social influences', 'emotion', and 'self-regulation/action planning'), were used to describe perceived implementation difficulties, predict self-reported implementation behaviours, and explore relationships with demographic and professional variables. RESULTS: The overall response rate was 43% (n?=?589). The number of questionnaires analysed was 364, following removal of the delivery-unit midwives, who are not directly involved in providing smoking-cessation services. Participants reported few implementation difficulties, high levels of motivation for all four behaviours and identified smoking-cessation work with their role. Midwives were less certain about the consequences of, and the environmental context and resources available for, engaging in this work relative to other TDF domains. All domains were highly correlated. A principal component analysis showed that a single factor ('propensity to act'), derived from all domains, explained 66% of variance in theoretical domain measures. The 'propensity to act' was predictive of the self-reported behaviour 'Refer all women who smoke……to NHS Stop Smoking Services' and mediated the relationship between demographic variables, such as midwives' main place of work, and behaviour. CONCLUSIONS: Our findings advance understanding of what facilitates and inhibits midwives' guideline implementation behaviours in relation to smoking cessation and will inform the development of current practice and new interventions. Using the TDF as a self-completion questionnaire is innovative, and this study supports previous research that the TDF is an appropriate tool to understand the behaviour of healthcare professionals.     

Smoking and the sudden infant death syndrome: results from 1993-5 case-control study for confidential inquiry into stillbirths and deaths in infancy. Confidential Enquiry into Stillbirths and Deaths Regional Coordinators and Researchers.

OBJECTIVE--To investigate the effects of exposure to tobacco smoke and of parental consumption of alcohol and illegal drugs as risk factors for the sudden infant death syndrome after a national risk reduction campaign which included advice on prenatal and postnatal avoidance of tobacco smoke. DESIGN--Two year population based case-control study. Parental interviews were conducted for each infant who died and four controls matched for age and date of interview. SETTING--Three regions in England with a total population of 17 million people. SUBJECTS--195 babies who died and 780 matched controls. RESULTS--More index than control mothers (62.6% v 25.1%) smoked during pregnancy (multivariate odds ratio = 2.10; 95% confidence interval 1.24 to 3.54). Paternal smoking had an additional independent effect when other factors were controlled for (2.50; 1.48 to 4.22). The risk of death rose with increasing postnatal exposure to tobacco smoke, which had an additive effect among those also exposed to maternal smoking during pregnancy (2.93; 1.56 to 5.48). The population attributable risk was over 61%, which implies that the numbers of deaths from the syndrome could be reduced by almost two third if parents did not smoke. Alcohol use was higher among index than control mothers but was strongly correlated with smoking and on multivariate analysis was not found to have any additional independent effect. Illegal drug use was more common among the index parents, and paternal use of illegal drugs remained significant in the multivariate model (4.68; 1.56 to 14.05). CONCLUSIONS--This study confirms the increased risk of the sudden infant death syndrome associated with maternal smoking during pregnancy and shows evidence that household exposure to tobacco smoke has an independent additive effect. Parental drug misuse has an additional small but significant effect.     

Intrusions in children's dietary recalls: the roles of BMI, sex, race, interview protocol, and social desirability

Dietary-reporting validation study data and school foodservice production records were used to examine intrusions (reports of uneaten items) in school meals in 24-h recalls. Fourth-grade children [20 low-BMI (> or = 5th and < 50th percentiles); 20 high-BMI (> or = 85th percentile); 50% boys; 75% black] were each observed eating two school meals (breakfast, lunch) and interviewed about the prior 24h that evening (24E) or the previous day the next morning (PDM). Social desirability was assessed. Intrusions were classified as stretches (on meal tray), internal confabulations (in school foodservice environment but not on meal tray), and external confabulations (not in school foodservice environment). For breakfast, reported items were less likely to be intrusions for black than white children, and for low-BMI boys than the other BMI-x-sex groups, and to be external confabulations for high-BMI girls than high-BMI boys. For lunch, reported items and intrusions were more likely to be stretches for 24E than PDM interviews. As social desirability increased, fewer items were reported for breakfast, and reported items and intrusions were more likely to be internal confabulations for lunch. For breakfast, compared to low-BMI girls, as social desirability increased, intruded amounts were larger for high-BMI boys and smaller for high-BMI girls. For lunch, intruded amounts were smaller for high-BMI girls than the other BMI-x-sex groups. Amounts reported were smaller for stretches than internal confabulations and external confabulations for breakfast, and external confabulations for lunch. To better understand intrusions, dietary-reporting validation studies are needed with larger samples by BMI-group, sex, and race.     

Cotinine levels and self-reported smoking status in patients attending a bronchoscopy clinic

The reliability of self-reported smoking behaviour can vary and may result in bias if errors in misclassification vary with outcome. We examined whether self-report was an accurate measure of current smoking status in patients with malignant or non-malignant respiratory disease. Smoking behaviour was assessed by self-report and by analysis of whole blood for cotinine, a biomarker of exposure to cigarette smoke, in 166 patients attending a bronchoscopy clinic. Cotinine levels ranged from 2.5 to &gt;400 ng ml^?1 blood and were higher in self-reported current smokers (173±123 ng ml^?1) than in never smokers (3.7±8.7 ng ml^?1) or ex-smokers (20.5±49.0 ng ml^?1). Cotinine levels in self-reported current smokers increased with the numbers of cigarettes smoked (p=0.06), and levels in smokers and ex-smokers decreased with the reported length of time since the last cigarette (p=0.001). Using a cotinine level of 20 ng ml^?1 and self-report as the gold standard, the sensitivity and specificity for defining current smoking status were 90.2% and 82.4%, respectively. Out of a total of 125 self-reported current non-smokers, 23 (18.4%) had cotinine levels greater than 20 ng ml^?1. Smoking prevalence was significantly underestimated by self-report (24.7%) when compared with that defined using blood cotinine levels (36.1%: p&lt;0.001). Misclassification of current smoking status was particularly high in ex-smokers, in patients without malignant respiratory disease, in men, and in those below the median age. Such differential misclassification may result in bias in studies examining associations between current smoking habits and disease risk.     

Human urine mutagenicity study comparing cigarettes which burn or only heat tobacco

Cigarette smokers have been reported to void urine which is more mutagenic, as measured in the Ames bacterial mutation assay, than urine voided by non-smokers. Condensate from the mainstream smoke of a cigarette which heats, but does not burn tobacco (test cigarette) showed no evidence of mutagenicity in a battery of in vitro genotoxicity assays under conditions in which condensate from the mainstream smoke of cigarettes that burn tobacco was mutagenic. The objective of this study was to determine whether the absence of mutagenic activity observed in the in vitro assays would be reflected in the urine of smokers of the test cigarette. 72 subjects (31 smokers and 41 non-smokers) were enrolled in a 6-week study, with the smokers randomly divided into 2 groups. The study was designed as a double crossover, with each smoker smoking both test (tobacco-heating) and reference (tobacco-burning) cigarettes. This design allowed each smoker to serve as his or her own control while at the same time allowing comparisons between groups of non-smokers and smokers of both test and reference cigarettes. 24-h urine samples were collected twice a week and concentrated using XAD-2 resin. Urine concentrates were tested in Ames bacterial strains TA98 and TA100, with and without metabolic activation and with and without beta-glucuronidase/aryl sulfatase. Individuals who smoked the test cigarette voided urine which was significantly less mutagenic than that voided when they smoked reference cigarettes. The mutagenicity of urine from smokers who smoked the test cigarette and non-smokers did not differ under any of the assay conditions used in this study.