Validity of cigarette smoking habits in three epidemiologic studies in Utah

The effect of cigarette smoking on the oral microbiota in a South African population using subgingival plaque samples

Disturbances in the oral microbiota may be due to several mechanisms and factors, such as smoking. An imbalance in oral bacteria may result in changes to the innate immune system and the development of periodontal disease. This study aimed to investigate the distribution of oral microbiota in smokers and non-smokers in a South African population using subgingival plaque samples. From the 128 recruited participants, 57 were identified as smokers (serum cotinine: >15 ng/ml). Analysis of 16S rRNA gene sequencing demonstrated significant differences between the two groups with a reduced abundance of Actinobacteria in smokers. Fusobacterium and Campylobacter were found in higher abundance, while a lower abundance of Leptotrichia, Actinomyces, Corynebacterium, and Lautropia were observed. This study highlighted significant differences in the oral microbiota of smokers, indicating an abundance of anaerobic gram-negative bacteria. These findings suggest that smoking allows certain oral microorganisms to gain dominance, thereby predisposing individuals to periodontal disease development and progression.

Misclassification of smoking habits: An updated review of the literature

BACKGROUND

Misclassification of smoking habits leads to underestimation of true relationships between diseases and active smoking, and overestimation of true relationships with passive smoking. Information on misclassification rates can be obtained from studies using cotinine as a marker.

AIM

To estimate overall misclassification rates based on a review and meta-analysis of the available evidence, and to investigate how misclassification rates depend on other factors.

METHODS

We searched for studies using cotinine as a marker which involved at least 200 participants and which provided information on high cotinine levels in self-reported non-, never, or ex-smokers or on low levels in self-reported smokers. We estimated overall misclassification rates weighted on sample size and investigated heterogeneity by various study characteristics. Misclassification rates were calculated for two cotinine cut points to distinguish smokers and non-smokers, the higher cut point intended to distinguish regular smoking.

RESULTS

After avoiding double counting, 226 reports provided 294 results from 205 studies. A total of 115 results were from North America, 128 from Europe, 25 from Asia and 26 from other countries. A study on 6.2 million life insurance applicants was considered separately. Based on the lower cut point, true current smokers represented 4.96% (95% CI 4.32-5.60%) of reported non-smokers, 3.00% (2.45-3.54%) of reported never smokers, and 10.92% (9.23-12.61%) of reported ex-smokers. As percentages of true current smokers, non-, never and ex-smokers formed, respectively, 14.50% (12.36-16.65%), 5.70% (3.20-8.20%), and 8.93% (6.57-11.29%). Reported current smokers represented 3.65% (2.84-4.45%) of true non-smokers. There was considerable heterogeneity between misclassification rates. Rates of claiming never smoking were very high in Asian women smokers, the individual studies reporting rates of 12.5%, 22.4%, 33.3%, 54.2% and 66.3%. False claims of quitting were relatively high in pregnant women, in diseased individuals who may recently have been advised to quit, and in studies considering cigarette smoking rather than any smoking. False claims of smoking were higher in younger populations. Misclassification rates were higher in more recently published studies. There was no clear evidence that rates varied by the body fluid used for the cotinine analysis, the assay method used, or whether the respondent was aware their statements would be validated by cotinine - though here many studies did not provide relevant information. There was only limited evidence that rates were lower in studies classified as being of good quality, based on the extent to which other sources of nicotine were accounted for.

CONCLUSION

It is important for epidemiologists to consider the possibility of bias due to misclassification of smoking habits, especially in circumstances where rates are likely to be high. The evidence of higher rates in more recent studies suggests that the extent of misclassification bias in studies relating passive smoking to smoking-related disease may have been underestimated.

Overview of Cotinine Cutoff Values for Smoking Status Classification

While cotinine is commonly used as a biomarker to validate self-reported smoking status, the selection of an optimal cotinine cutoff value for distinguishing true smokers from true nonsmokers shows a lack of standardization among studies. This review describes how the cutoff values have been derived, and explains the issues involved in the generalization of a cutoff value. In this study, we conducted an English-language literature search in PubMed using the keywords “cotinine” and “cutoff” or “self-reported” and “smoking status” and “validation” for the years 1985–2014. We obtained 104 articles, 32 of which provided (1) sensitivity and specificity of a cutoff value and (2) determination methods for the given cutoff value. We found that the saliva cotinine cutoff value range of 10–25 ng/mL, serum and urine cotinine cutoff of 10–20 ng/mL and 50–200 ng/mL, respectively, have been commonly used to validate self-reported smoking status using a 2 × 2 table or a receiver operating characteristics (ROC) curve. We also found that recent large population-based studies in the U.S. and UK reported lower cutoff values for cotinine in serum (3 ng/mL) and saliva (12 ng/mL), compared to the traditionally accepted ones (15 and 14 ng/mg, respectively).

Nicotine dependence and smoking cessation after hospital discharge among inpatients with coronary heart attacks

This study focuses on the predictability of two alternative questionnaires for nicotine dependence, i.e., the Fagerstrom Tolerance Questionnaire (FTQ) and the Tobacco Dependence Screener (TDS), each of which represents a different aspect of dependence, among patients with coronary heart disease (CHD). Twenty-nine male inpatients that had been newly diagnosed as CHD were followed up for 30 weeks after hospital discharge. The baseline information included age, number of cigarettes per day, years of smoking, disease type (angina pectoris [AP] or acute myocardial infarction [AMI), whether they had received a briefing on smoking cessation, the FTQ, and the TDS. At 30 weeks after hospital discharge, 19 (66%) were abstainers. The group with a high TDS score (of 6 or greater) was significantly less likely to quit smoking than the group with a low TDS score (p=0.046). The FTQ score was not significantly different between the abstainers and non-abstainers. The subjects with AP were significantly less likely to quit smoking than those with AMI (p=0.021). Multiple logistic regression analysis showed that belonging to the high-TDS group and being diagnosed as AP were significantly associated with failure in smoking cessation (p<0.05). The present study suggests that the TDS may have higher predictability than the FTQ concerning smoking cessation among CHD inpatients.

Mitochondrial DNA copy number and pancreatic cancer in the alpha-tocopherol beta-carotene cancer prevention study

Diabetes, obesity, and cigarette smoke, consistent risk factors for pancreatic cancer, are sources of oxidative stress in humans that could cause mitochondrial DNA (mtDNA) damage and increase mtDNA copy number. To test whether higher mtDNA copy number is associated with increased incident pancreatic cancer, we conducted a nested case-control study in the Alpha-Tocopherol Beta Carotene Cancer Prevention (ATBC) Study cohort of male smokers, aged 50 to 69 years at baseline. Between 1992 and 2004, 203 incident cases of pancreatic adenocarcinoma occurred (follow-up: 12 years) among participants, with whole blood samples used for mtDNA extraction. For these cases and 656 controls, we calculated ORs and 95% CIs using unconditional logistic regression, adjusting for age, smoking, and diabetes history. All statistical tests were two sided. Higher mtDNA copy number was significantly associated with increased pancreatic cancer risk (highest vs. lowest mtDNA copy number quintile, OR = 1.64, 95% CI = 1.01-2.67, continuous OR = 1.14, 95% CI 1.06-1.23), particularly for cases diagnosed during the first 7 years of follow-up (OR = 2.14, 95% CI = 1.16-3.96, P(trend) = 0.01, continuous OR = 1.21, 95% CI = 1.10-1.33), but not for cases occurring during follow-up of 7 years or greater (OR = 1.14, 95% CI = 0.53-2.45, continuous OR = 1.05, 95% CI = 0.93-1.18). Our results support the hypothesis that mtDNA copy number is associated with pancreatic cancer and could possibly serve as a biomarker for pancreatic cancer development.

Vitamin E intake, alpha-tocopherol status, and pancreatic cancer in a cohort of male smokers

BACKGROUND

Evidence indicates that vitamin E has anticarcinogenic properties for gastrointestinal cancers; however, few studies have examined this with respect to exocrine pancreatic cancer.

OBJECTIVE

The objective was to examine whether vitamin E intake and serum alpha-tocopherol concentrations were prospectively associated with exocrine pancreatic cancer.

DESIGN

We conducted a cohort analysis of prediagnostic vitamin E intake (4 tocopherols, 4 tocotrienols), serum alpha-tocopherol concentrations, and pancreatic cancer in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study of male Finnish smokers aged 50-69 y at baseline. During follow-up from 1985 to 2004 (maximum: 19.4 y; median: 16 y), 318 incident cases were diagnosed among cohort participants with complete serum samples (n = 29,092); 306 cases had complete dietary data (n = 27,111). Cox proportional hazards models adjusted for age, smoking history, history of diabetes mellitus, and/or serum cholesterol were used to calculate hazard ratios (HRs) and 95% CIs.

RESULTS

Higher alpha-tocopherol concentrations were associated with lower pancreatic cancer risk (highest compared with lowest quintile, HR: 0.52; 95% CI: 0.34, 0.80; P for trend = 0.03; continuous HR: 0.91; 95% CI: 0.84, 0.99). Polyunsaturated fat, a putative prooxidant nutrient, modified the association such that the inverse alpha-tocopherol association was most pronounced in subjects with a high polyunsaturated fat intake (ie, >9.9 g/d; highest compared with lowest quintile, HR: 0.38; 95% CI: 0.20, 0.70; P for trend = 0.03; continuous HR: 0.86; 95% CI: 0.75, 0.97; P for interaction = 0.05 and 0.02, respectively). No associations were observed for dietary tocopherols and tocotrienols.

CONCLUSION

Our results support the hypothesis that higher alpha-tocopherol concentrations may play a protective role in pancreatic carcinogenesis in male smokers.

The accuracy of self-reported smoking: a systematic review of the relationship between self-reported and cotinine-assessed smoking status

INTRODUCTION

Smoking is a leading cause of premature mortality and preventable morbidity. Surveillance is most often based on self-reported data, but studies have shown that self-reports tend to underestimate smoking status.

METHODS

This study systematically reviewed the literature to measure the concordance between self-reported smoking status and smoking status determined through measures of cotinine in biological fluids. Four electronic databases were searched to identify observational and experimental studies on adult populations over the age of 18 years.

RESULTS

Searching identified 67 studies that met the eligibility criteria and examined the relationship between self-reported smoking and smoking confirmed by cotinine measurement. Overall, the data show trends of underestimation when smoking prevalence is based on self-report and varying sensitivity levels for self-reported estimates depending on the population studied and the medium in which the biological sample is measured. Sensitivity values were consistently higher when cotinine was measured in saliva instead of urine or blood. Meta-analysis was not appropriate because of the substantial heterogeneity among the cutpoints used to define smokers and the poor reporting on outcomes of interest.

DISCUSSION

Further research in this field would benefit from the standardization of cutpoints to define current smokers and the implementation of standard reporting guidelines to enhance comparability across studies. Accurate estimation of smoking status is important as data from population studies such as those included in this review are used to generate regional and national estimates of smoking status and in turn are used to allocate resources and set health priorities.

Cigarette smoking and risk of breast carcinoma in situ

BACKGROUND

Although the associations with cigarette smoking have been explored extensively for invasive breast cancer, the relation to in situ cancer has not previously been examined in depth.

METHODS

We analyzed data from a population-based case-control study of women living in Wisconsin, Massachusetts, and New Hampshire. Eligible cases of incident breast carcinoma in situ were reported to statewide registries in 1997-2001 (n = 1878); similarly aged controls (n = 8041) were randomly selected from population lists. Smoking history and other risk factor information were collected through structured telephone interviews. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated from logistic regression models adjusting for potential confounders.

RESULTS

In multivariate models, the OR for breast carcinoma in situ among current smokers was 0.8, compared with never-smokers (95% CI = 0.7-1.0). Risk estimates increased towards the null with greater time since smoking cessation. Odds ratios were also less than 1.0 among women who initiated smoking in adolescence (OR = 0.8) or after a full-term birth (OR = 0.7), relative to women who never smoked. The reduced odds ratios associated with current smoking were strongest among women with annual screening mammograms (OR = 0.7; 95% CI = 0.6-0.9). Odds ratios were not less than 1.0 among current smokers without a recent screening mammogram (1.3; 0.9-2.0).

CONCLUSIONS

Our findings suggest an inverse association between current smoking and risk of breast carcinoma in situ among women undergoing breast cancer screening.

Salivary cotinine concentration versus self-reported cigarette smoking: Three patterns of inconsistency in adolescence

The present study examined the extent and sources of discrepancies between self-reported cigarette smoking and salivary cotinine concentration among adolescents. The data are from household interviews with a cohort of 1,024 adolescents from an urban school system. Histories of tobacco use in the last 7 days and saliva samples were obtained. Logistic regressions identified correlates of three inconsistent patterns: (a) Pattern 1-self-reported nonsmoking among adolescents with cotinine concentration above the 11.4 ng/mg cutpoint (n = 176), (b) Pattern 2-low cotinine concentration (below cutpoint) among adolescents reporting having smoked within the last 3 days (n = 155), and (c) Pattern 3-high cotinine concentration (above cutpoint) among adolescents reporting not having smoked within the last 3 days (n = 869). Rates of inconsistency were high among smokers defined by cotinine levels or self-reports (Pattern 1 = 49.1%; Pattern 2 = 42.0%). Controlling for other covariates, we found that reports of nonsmoking among those with high cotinine (Pattern 1) were associated with younger age, having few friends smoking, little recent exposure to smokers, and being interviewed by the same interviewer as the parent and on the same day. Low cotinine concentration among self-reported smokers (Pattern 2) was negatively associated with older age, being African American, number of cigarettes smoked, depth of inhalation, and exposure to passive smoke but positively associated with less recent smoking and depressive symptoms. High cotinine concentrations among self-reported nonsmokers was positively associated with exposure to passive smoke (Pattern 3). The data are consonant with laboratory findings regarding ethnic differences in nicotine metabolism rate. The inverse relationship of cotinine concentration with depressive symptoms has not previously been reported. Depressed adolescent smokers may take in smaller doses of nicotine than nondepressed smokers; alternatively, depressed adolescents may metabolize nicotine more rapidly.

Indoor radon and lung cancer risk in connecticut and utah

Radon is a well-established cause of lung cancer in miners. Residents of homes with high levels of radon are potentially also at risk. Although most individual studies of indoor radon have failed to demonstrate significant risks, results have generally been consistent with estimates from studies of miners. We studied 1474 incident lung cancer cases aged 40-79 yr in Connecticut, Utah, and southern Idaho. Population controls (n = 1811) were identified by random telephone screening and from lists of Medicare recipients, and were selected to be similar to cases on age, gender, and smoking 10 yr before diagnosis/interview using randomized recruitment. Complete residential histories and information on known lung cancer risk factors were obtained by in-person and telephone interviews. Radon was measured on multiple levels of past and current homes using 12-mo alpha-track etch detectors. Missing data were imputed using mean radon concentrations for informative subgroups of controls. Average radon exposures were lower than anticipated, with median values of 23 Bq/m3 in Connecticut and 45 Bq/m3 in Utah/southern Idaho. Overall, there was little association between time-weighted average radon exposures 5 to 25 yr prior to diagnosis/interview and lung cancer risk. The excess relative risk (ERR) associated with a 100-Bq/m3 increase in radon level was 0.002 (95% CI -0.21, 0.21) in the overall population, 0.134 (95% CI -0.23, 0.50) in Connecticut, and -0.112 (95% CI -0.34, 0.11) in Utah/Idaho. ERRs were higher for some subgroups less prone to misclassification, but there was no group with a statistically significant linear increase in risk. While results were consistent with the estimates from studies of miners, this study provides no evidence of an increased risk for lung cancer at the exposure levels observed.

[Household smoking and respiratory disease in under-five children]

Environmental tobacco smoke is an important respiratory tract irritant in young children. To identify factors associated with respiratory disease and determine the main source of smoking exposure in the household, a cross-sectional study of 2,037 children who were immunized in primary health care clinics was conducted (in a sample of 10 out of 38 clinics with 200 children each). Parents answered a questionnaire about children's birth, passive smoking, former and current respiratory morbidity, socio-demographic characteristics, and living conditions. Analysis was based on hierarchical logistic regression. Prevalence of respiratory symptoms was 59.9% for children who live with smokers. Asthma and bronchitis showed the strongest association with smoking. In multivariate logistic regression, the following variables remained associated with asthma/bronchitis: socioeconomic status (OR = 2.93; 95%CI: 1.57-5.45), maternal schooling (OR = 1.46; 95%CI: 1.08-1.98)] and occupation (OR = 1.68; 95%CI: 1.04-2.74), neighborhood (OR = 1.47; 95%CI: 1.06-2.02), child's age (OR = 3.38; 95%CI: 2.31-4.95) and sex (OR = 1.46; 95%CI: 1.09-1.94), breastfeeding (OR = 1.66; 95%CI: 1.15-2.40), and household smoking (OR = 1.58; 95%CI: 1.18-2.11). Children with lower socioeconomic status and exposed to household smoking showed increased risk of respiratory disease.

[Household smoking and stunting for children under five years]

Maternal tobacco use during pregnancy is one of the most important factors for low birth weight and length. However, postnatal exposure to environmental tobacco smoke has not been explored in children's growth studies. It is known that smoking is more prevalent in low socioeconomic groups and that stunting is also associated with socioeconomic variables. The objective of this study was to verify the effect of socioeconomic variables and environmental tobacco smoke on growth. Children under five years (n = 2,037) attending a primary health care clinic had their weight and stature measured, and a questionnaire on exposure to household passive smoking and socio-demographic characteristics was applied to parents. Prevalence of stunting (defined as a z-score lower than -2) was 4.3%. There was a negative association between stature and smoking during pregnancy, and positive associations with socioeconomic levels, family income, and parents' education. Linear hierarchical regression analysis showed that maternal and paternal smoking remains associated with low stature even after adjusting for maternal smoking during pregnancy and for socio-demographic variables.

A randomized controlled trial of smoking cessation counseling after myocardial infarction

BACKGROUND

Smoking cessation after myocardial infarction (MI) has been associated with a 50% reduction in mortality but in-hospital smoking cessation interventions are rarely part of routine clinical practice.

METHODS

One hundred cigarette smokers consecutively admitted during 1996 with MI were assigned to minimal care or to a hospital-based smoking cessation program. Intervention consisted of bedside cessation counseling followed by seven telephone calls over the 6 months following discharge. Primary outcomes were abstinence rates measured at 6 months and 1 year post-discharge.

RESULTS

At follow-up, 43 and 34% of participants in minimal care and 67 and 55% of participants in intervention were abstinent at 6 and 12 months. respectively (P<0.05). Abstinence rates were calculated assuming that participants lost to attrition were smokers at follow-up. Intervention and self-efficacy were independent predictors of smoking status at follow-up. Low self-efficacy combined with no intervention resulted in a 93% relapse rate by 1 year (P<0.01).

CONCLUSIONS

A hospital-based smoking cessation program consisting of inpatient counseling and telephone follow-up substantially increases smoking abstinence 1 year after discharge in patients post-MI. Patients with low self-efficacy are almost certain to relapse without intervention. Such smoking cessation programs should be part of the management of patients with MI.

The accuracy of self-reported health behaviors and risk factors relating to cancer and cardiovascular disease in the general population: a critical review

OBJECTIVE

To critically review the literature concerning the accuracy of self-reported health behaviors and risk factors relating to cancer and cardiovascular disease among the general population.

METHOD

A literature search was conducted on three major health research databases: MEDLINE, HealthPLAN, and PsychLit. The bibliographies of located articles were also checked for additional relevant references. Studies meeting the following five inclusion criteria were included in the review: They were investigating the accuracy of self-report among the general population, as opposed to among clinical populations. They employed an adequate and appropriate gold standard. At least 70% of respondents consented to validation, where validation imposed minimal demands on the respondent; and 60% consent to validation was considered acceptable where validation imposed a greater burden. They had a sample size capable of estimating sensitivity and specificity rates with 95% confidence intervals of width +/-10%. The time lag between collection of the self-report and validation data for physical measures did not exceed one month.

RESULTS

Twenty-four of 66 identified studies met all the inclusion criteria described above. In the vast majority, self-report data consistently underestimated the proportion of individuals considered "at-risk." Similarly, community prevalences of risk factors were considerably higher according to gold standard data sources than they were according to self-report data.

CONCLUSIONS

This review casts serious doubts on the wisdom of relying exclusively on self-reported health information. It suggests that caution should be exercised both when trying to identify at-risk individuals and when estimating the prevalence of risk factors among the general population. The review also suggests a number of ways in which the accuracy of individuals' self-reported health information can be maximized.

Comparing smoking and smoking cessation process in the Republic of Karelia, Russia and North Karelia, Finland

STUDY OBJECTIVE

The aims of this study were to assess and validate self reported smoking prevalence and to assess smoking cessation related process variables in the Republic of Karelia, Russia and in North Karelia, Finland.

DESIGN

Comparative population surveys of random population samples from both areas in spring 1992. The study included a self administered questionnaire, physical measurements and laboratory tests. The validity of self reported smoking prevalence was assessed by serum cotinine analyses.

SETTING

The district of Pitkäranta in the Republic of Karelia, Russia and province of North Karelia, Finland.

PARTICIPANTS

The study population was a 25 to 64 year old population in both areas. A stratified random sample of 1000 people in Pitkäranta and 2000 people in North Karelia was drawn from the population registers. In Pitkäranta 380 men and 455 women, and in North Karelia 673 men and 803 women, participated in the survey.

RESULTS

The self reported prevalence rates of daily smoking in Pitkäranta were 65% among men and 10% among women. In North Karelia the respective rates were 29% and 13%. Women in Pitkäranta greatly underreported their smoking status, which was assessed by comparing the self reported data to the serum cotinine measurements. The smoking prevalence among women in Pitkäranta would rise from 10% to 21% if all participants with high cotinine values would be regarded as smokers. Compared with smokers in North Karelia, a higher percentage of smokers in Pitkäranta expressed their wish to quit and believed that they would succeed. However, on average they had fewer previous smoking cessation attempts than smokers in North Karelia. In addition, the health personnel in North Karelia were more active in advising smokers to quit.

CONCLUSIONS

High smoking prevalence among men in Pitkäranta obviously contributes much to the high premature death rate in the Republic of Karelia. There is considerable underreporting of smoking in Pitkäranta, especially among women, which is probably attributable to the cultural unacceptability of female smoking in Russia. The common wish to quit, few previous cessation attempts and much lower rates of ex smokers, together with less smoking cessation counselling from health personnel, need to be considered in tailoring antismoking interventions in the area.

Maternal cigarette smoking and child psychiatric morbidity: a longitudinal study

OBJECTIVE

Previous studies have linked maternal smoking during pregnancy with behavioral disturbance in children. However, additional evidence is needed to address the causality of the relationship. The present study analyses result from an Australian cohort of 5342 5-year-old children whose mothers were recruited early in pregnancy.

METHODS

Smoking history was gathered for prepregnancy, first clinic visit (FCV), late pregnancy, and when the child was 6 months and 5 years of age. Behavior problems at the age of 5 were assessed using a modified Child Behavior Check List (CBCL) shown to have high agreement with the complete CBCL. This resulted in the formation of three scales: internalizing; social, attentional and thought; and externalizing behavior problems, which were then dichotimized at the 90th percentile in each case. Logistic regression was used to model these outcomes as a function of maternal smoking at five time points during which it was assessed. A series of models explored the effect of additional adjustment for confounding. The predictors of attrition (29.5%) throughout the cohort were also identified by multivariate modeling.

RESULTS

The final analysis was carried out on a cohort of mother-child pairs for whom data and child behavior outcomes were complete. The mean age of children was 5 years, 6 months with a range from 4 to 6 years. The mean age of mothers at the time of birth of the child was 25 years, with a range from 13 to 47 years. Mothers lost to follow-up were more likely to be younger, single, and less well-educated than those who continued participation, although maternal smoking was not an independent determinant. Unadjusted analyses showed strong associations between externalizing child behavior and maternal smoking during pregnancy and at the 5-year follow-up, with relative risks (RRs) up to 2.6 for children of women smoking at least 20 cigarettes per day at the first antenatal clinic visit. A clear dose-response relationship existed in most relationships with higher levels of smoking being associated with higher rates of externalizing behavior problems. Weaker relationships occurred for internalizing behavior and social, attentional and thought behavior problems. Multivariate analysis of the timing in more detail that the association between maternal smoking and child behavior problems persisted, although the evidence for dose-response diminished. Moreover, it was primarily associated with smoking as determined by questions asked at the FCV (RR = 1.52, 2.03, 2.16) for 1 to 9, 10 to 19, and >/=20 cigarettes per day, respectively, compared with nonsmoking and secondarily by smoking determined at the 5-year follow-up (RR = 1.52, 1.87, 1.29) for 1 to 9, 10 to 19, and >/=20 cigarettes per day respectively, compared with nonsmoking. This association appeared to be independent of a wide range of possible confounders such as maternal age, education, social class, marital status and mental health, gestation at FCV, complications during pregnancy, the child's sex, gestational age at birth, and age at last follow-up. Adjustments were also made for the mother's employment since birth, family structure, and maternal mental health at the time of the CBCL assessment. Associations between externalizing behavior problems and maternal smoking at other times, and those between other behavioral problems examined and maternal smoking were not significant.

CONCLUSION

Although previous studies have found evidence for an association between maternal smoking and child behavior problems, the strength of this study lies in its size, its detailed and consistent measurement of maternal smoking, and its ability to control for many social and biological factors linked to maternal smoking and child behavior. (ABSTRACT TRUNCATED)

Cigarette smoking and rheumatoid arthritis severity

OBJECTIVES

Cigarette smoking may influence rheumatoid arthritis (RA) disease incidence and may have direct biological effects on the lungs and systemically. This study sought to determine if cigarette smoking is associated with RA disease severity.

METHODS

Clinical evaluations of patients seen in the University of Iowa rheumatology and orthopaedic ambulatory clinics were conducted. A letter of interest was mailed to 1701 patients who were first assigned an ICD-9-CM diagnostic code for RA in one of these clinics. A total of 857 patients expressed interest and were offered a clinical examination and 395 were evaluated over an 18 month period. Of these, 336 satisfied examiner criteria for prevalent RA and were included in the analysis. The disease characteristics and arthritis care utilisation of these patients seemed representative of prevalent cases in the general community. RA disease severity was assessed by radiographic bone erosions (graded as either present/ absent and using the Larsen system), rheumatoid factor seropositivity, and presence of subcutaneous rheumatoid nodules.

RESULTS

Pack years of cigarette smoking was significantly associated with rheumatoid factor seropositivity (p = 0.0001), radiographic erosions (p = 0.024), and nodules (p = 0.051). After adjustment for potential confounders, smokers with > or = 25 pack years were 3.1 times more likely to be rheumatoid factor positive (95% CI 1.7, 5.6) and 2.4 times more likely to show radiographic erosions (95% CI 1.2, 4.5) than never smokers. Less severe radiographic disease seemed to be more strongly associated with cigarette smoking than more severe disease.

CONCLUSION

Cigarette smoking may adversely influence the severity of RA in a potentially dose dependent fashion.

The internal dose of passive smoking at home depends on the size of the dwelling

As part of a longitudinal study two urine samples (survey 1 in 1991 and survey 2 in 1992) were collected from 602 elementary school children to investigate the relationship between urinary cotinine excretion (UCE) and the daily consumption of cigarettes at home (exposure). Size of the dwelling, educational level, and maternal smoking were taken into consideration as additional predictors. The history regarding parental smoking habits and confounding variables was ascertained by standardized questionnaires completed by the parents. Cotinine was measured using gas chromatography selected ion monitoring. UCE was expressed as cotinine/creatinine (ng/mg). In children with detectable UCE in survey 1 (35%) and in survey 2 (44%) the excretion ranged between 1.5 and 24.7 ng/mg (5-95%) and between 1.2 and 25.2 ng/mg, respectively. UCE measurements in both surveys were highly correlated (r = 0.65, P = 0.0001), and 59.6% of the UCE in survey 2 can be explained in linear regression by the UCE in survey 1. Using multiple linear regression, the categorized number of cigarettes reported to be consumed at home (20 cigarettes and more: 1991, P = 0.0001; 1992, P = 0.0003) and low educational level of the parents (P = 0.011 in 1991, P = 0.04 in 1992) were positively associated with UCE, whereas the size of the dwelling turned out to be negatively associated with UCE (P = 0.12 in 1991, P = 0.001 in 1992). In small dwellings (< or = 80 m2) the effect of exposure on UCE was much more pronounced. In conclusion, a single UCE measurement provides information which is widely stable within a yearly interval and is related to passive smoke history as well as to socio-economic status and the size of the dwelling. The latter variable should be considered as an effect modifier of exposure on internal dose and should be taken into account in future studies on passive smoke exposure.

Rheumatoid arthritis lung disease. Determinants of radiographic and physiologic abnormalities

OBJECTIVE

To determine the prevalence and important clinical predictors of radiographic and physiologic abnormalities indicative of rheumatoid arthritis interstitial lung disease (RA-ILD).

METHODS

An unselected cohort of patients with a confirmed diagnosis of RA and known lung disease were identified (n = 336) and evaluated for RA disease activity and severity. Outcomes included abnormalities determined by the pulmonary function tests of forced vital capacity (FVC) and diffusion capacity for carbon monoxide (DLco), and/or chest radiographic findings of interstitial infiltrates. We used multivariable statistical modeling to determine the independent significance of cigarette smoking and other RA-specific factors on the pulmonary abnormalities of interest.

RESULTS

At least 1 of the 3 abnormal findings was identified by pulmonary tests in 32.4% of all patients. These abnormal findings included an FVC < 80% of predicted in 42 patients, a DLco < 80% of predicted in 64 patients, and evidence of radiographic interstitial infiltrates in 40 patients. After statistical adjustment for confounding factors, pack-years of cigarette smoking remained a significant predictor of low DLco (beta = -0.07, 95% confidence interval [95% CI] -0.09, -0.04), low FVC (beta = -0.003, 95% CI -0.006, -0.0004), and interstitial abnormalities on chest radiograph (odds ratio for > or = 25 pack-years = 3.76, 95% CI 1.59, 8.88). The Health Assessment Questionnaire (HAQ) Disability Index (DI) was also an important risk factor for the decline in both the DLco (beta = -1.15, 95% CI -2.00, -0.30) and FVC (beta = -0.23, 95% CI -0.32, -0.13).

CONCLUSION

Although RA disease activity/severity (particularly as defined by the HAQ DI) was important, smoking was the most consistent independent predictor of radiographic and physiologic abnormalities suggestive of ILD in RA.

The validity of self-reported smoking: a review and meta-analysis

OBJECTIVES

The purpose of this study was to identify circumstances in which biochemical assessments of smoking produce systematically higher or lower estimates of smoking than self-reports. A secondary aim was to evaluate different statistical approaches to analyzing variation in validity estimates.

METHODS

Literature searches and personal inquiries identified 26 published reports containing 51 comparisons between self-reported behavior and biochemical measures. The sensitivity and specificity of self-reports of smoking were calculated for each study as measures of accuracy.

RESULTS

Sensitivity ranged from 6% to 100% (mean = 87.5%), and specificity ranged from 33% to 100% (mean = 89.2%). Interviewer-administered questionnaires, observational studies, reports by adults, and biochemical validation with cotinine plasma were associated with higher estimates of sensitivity and specificity.

CONCLUSIONS

Self-reports of smoking are accurate in most studies. To improve accuracy, biochemical assessment, preferably with cotinine plasma, should be considered in intervention studies and student populations.

The validity of self-reported smoking: a review and meta-analysis

OBJECTIVES

The purpose of this study was to identify circumstances in which biochemical assessments of smoking produce systematically higher or lower estimates of smoking than self-reports. A secondary aim was to evaluate different statistical approaches to analyzing variation in validity estimates.

METHODS

Literature searches and personal inquiries identified 26 published reports containing 51 comparisons between self-reported behavior and biochemical measures. The sensitivity and specificity of self-reports of smoking were calculated for each study as measures of accuracy.

RESULTS

Sensitivity ranged from 6% to 100% (mean = 87.5%), and specificity ranged from 33% to 100% (mean = 89.2%). Interviewer-administered questionnaires, observational studies, reports by adults, and biochemical validation with cotinine plasma were associated with higher estimates of sensitivity and specificity.

CONCLUSIONS

Self-reports of smoking are accurate in most studies. To improve accuracy, biochemical assessment, preferably with cotinine plasma, should be considered in intervention studies and student populations.

Error in smoking measures: effects of intervention on relations of cotinine and carbon monoxide to self-reported smoking. The Lung Health Study Research Group

OBJECTIVES

Sources of measurement error in assessing smoking status are examined.

METHODS

The Lung Health Study, a randomized trial in 10 clinical centers, includes 3923 participants in a smoking cessation program and 1964 usual care participants. Smoking at first annual follow-up was assessed by salivary cotinine, expired air carbon monoxide, and self-report. Each of these measures is known to contain some error. Sensitivity and specificity were calculated by comparing a biochemical measure with self-report to produce an undifferentiated estimate of error. Classification error rates due to imprecision of the biochemical measures and to the error in self-report were estimated separately.

RESULTS

For cotinine compared with self-report, the sensitivity was 99.0% and the specificity 91.5%. For carbon monoxide compared with self-report, the sensitivity was 93.7% and the specificity 87.2%. The classification error attributed to self-report, estimated by comparing the results from intervention and control groups, was associated with the responses of 3% and 5% of participants, indicating a small but significant bias toward a socially desirable response.

CONCLUSIONS

In absolute terms in these data, both types of error were small.

Age and smoking-adjusted lung cancer incidence in a Utah county with a steel mill

In a recent study of urban air pollution, a Utah county with a steel mill was compared with a county without a steel mill. The result was that 38% of respiratory cancer deaths could be attributed to the air pollution emanating from the mill. Rates for smoking in this previous study were not adjusted, but assumed rats were similar in both counties. We used smoking information obtained from an ongoing radon and lung cancer case-control study to adjust for smoking, and no difference was found in incidence rates of respiratory cancer in the county with the steel mill, compared with the other urban counties and the rural counties among male and female nonsmokers and male smokers. There was a slight excess of lung cancer among female smokers in the county with the steel mill when compared with the other urban counties (rate ratio [RR] = 1.3, 95% confidence interval [95% CI] = 1.0-1.6), but there was no effect in nonsmoking women. We conclude that the findings of the previous study can be explained by differences in smoking rates between the county with the steel mill and the other counties.

Air pollution and fatal lung disease in three Utah counties

A unique situation found in two Utah counties has made it possible to estimate the fraction of respiratory cancer and nonmalignant respiratory disease (NMRD) deaths, which are attributable to community air pollution (CAP) in one county. The two counties were very similar in many ways, including low smoking rates, until a steel mill constructed during WW II caused substantial CAP in one of them. Subsequent differences in mortality rates from both respiratory cancer and NMRD are striking. A third county, similar to many counties outside Utah, was included in the analysis for comparison. In one county, 30-40% of the respiratory cancer and NMRD deaths were attributable to CAP. In this county, NMRD deaths (but not respiratory cancer deaths) were slightly more frequent than in Salt Lake County where smoking rates were twice as high.

Prevalence of lifestyle risk factors in a family practice

The prevalence of eight adverse lifestyle risk factors which are linked to increased morbidity and mortality was determined. Smoking, excess alcohol use, obesity, lack of exercise, lack of seatbelt use, use of hazardous transportation vehicles, and inadequate rest were studied. A random sample of 147 patients from a private family practice were selected in a cross-sectional survey. Data were collected by mailed questionnaire. The most prevalent adverse habits were lack of seatbelt use (71%) and sedentary lifestyle (44%). Patients with multiple adverse health habits had poorer self-reported physical as well as emotional well-being. Using a factor analysis of the correlations among eight habits, no significant clustering of habits emerged as indicators of high risk. Thus, no abbreviated list of adverse lifestyle risk factors for clinical use was found that could replace a complete review of risk factors.