Moderate Smokers (moderate + smoker)

Distribution by Scientific Domains


Selected Abstracts


Estimating treatment effects in randomized clinical trials with non-compliance: the impact of maternal smoking on birthweight

HEALTH ECONOMICS, Issue 5 2001
Barton H. Hamilton
Abstract This paper assesses the causal impact of late-term (8th month) maternal smoking on birthweight using data from a randomized clinical trial, in which some women were encouraged not to smoke, while others were not. The estimation of treatment effects in this case is made difficult as a result of the presence of non-compliers, women who would not change their smoking status, regardless of the receipt of encouragement. Because these women are not at risk of changing treatment status, treatment effect distributions may be difficult to construct for them. Consequently, the paper focuses on obtaining the distribution of treatment impacts for the sub-set of compliers found in the data. Because compliance status is not observed for all subjects in the sample, a Bayesian finite mixture model is estimated that recovers the treatment effect parameters of interest. The complier average treatment effect implies that smokers give birth to infants weighing 348 g less than those of non-smokers, on average, although the 95% posterior density interval contains zero. The treatment effect is stronger for women who were moderate smokers prior to pregnancy, implying a birthweight difference of 430 g. However, the model predicts that only about 22% of the women in the sample were at risk of changing their smoking behaviour in response to encouragement to quit. Copyright © 2001 John Wiley & Sons, Ltd. [source]


The effects of transdermal nicotine on inspection time

HUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 3 2002
J. C. Thompson
Abstract Rationale The acute administration of nicotine via a cigarette has been demonstrated to enhance inspection time (IT), a measure of rapid visual information processing, while the nicotinic antagonist mecamylamine impairs IT. However, as transdermal nicotine patches provide a slow delivery of nicotine, it is unclear if they produce similar effects to nicotine administered by more rapid methods. Objectives To examine the effects of transdermal nicotine on inspection time. Methods Ten moderate smokers were administered nicotine (21,mg/day) or placebo via a transdermal patch in a randomized, double-blind, repeated measures design. Subjects were administered the IT task at baseline, then 1, 3, and 6,h subsequent to patch application. Results The change in IT from baseline was significantly different in the nicotine condition, relative to placebo, at 3,h but not 1 or 6,h. Conclusions The findings suggest that nicotine administered via transdermal patches improves IT, but this improvement may be subject to tolerance. Data from previous studies on tolerance to the cognitive effects of nicotine have been inconclusive. However, the slow delivery of nicotine from patches may be more likely to produce such effects. Copyright © 2002 John Wiley & Sons, Ltd. [source]


Influence of previous pregnancy outcomes and continued smoking on subsequent pregnancy outcomes: an exploratory study in Australia

BJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 11 2008
M Mohsin
Objective, To examine the influence of continued smoking and previous pregnancy outcomes on subsequent pregnancy outcomes. Design, Retrospective descriptive epidemiological study. Setting, New South Wales, Australia, 1994,2004. Population, Mothers who delivered two consecutive singleton births. Methods, Bivariate and multiple logistic regression analyses were used to explore the influence of continued smoking on subsequent pregnancy outcomes. Main outcome measures, Subsequent preterm birth (PTB), low birthweight (LBW) and perinatal deaths. Results, The findings showed that in addition to maternal and neonatal characteristics, birth outcomes in subsequent pregnancies were affected by poor birth outcomes in previous pregnancy. Previous PTB, short birth interval, antenatal care, gestational diabetes and smoking habits in two successive pregnancies had relatively strong association with a subsequent PTB and LBW. Mothers who continued to smoke in subsequent pregnancies were more likely to have adverse pregnancy outcomes compared with others. A change from smoking in first pregnancy to not smoking in next pregnancy had reduced the chance of a subsequent PTB and LBW. The risk of a subsequent preterm and LBW delivery increased with the amount of smoking during the second pregnancy. For mothers who remain as moderate smokers in subsequent pregnancies, the odds ratios for a PTB and LBW delivery were significantly lower than those who remain as heavy smokers. Conclusions, Effective interventions to help women to stop smoking during pregnancy could reduce the risk of adverse obstetric and pregnancy outcomes. Strategies to reduce the prevalence of smoking during pregnancy may include intense intervention for women who have had smoking-related adverse outcomes in a previous pregnancy. [source]


Cigarette smoking is related to a decrease in semen volume in a population of fertile men

BJU INTERNATIONAL, Issue 2 2006
FÁBIO F. PASQUALOTTO
OBJECTIVE To evaluate the semen quality and hormonal levels in fertile men according to their level of cigarette smoking. SUBJECTS AND METHODS We evaluated 889 fertile men who came for a vasectomy for sterilization purposes. The men included 522 non-smokers, 143 mild smokers (<10 cigarettes/day), 154 moderate smokers (11,20/day), and 70 heavy smokers (>20/day). We evaluated sperm concentration, motility, motion variables and hormonal levels in these men. RESULTS There were no significant differences among the groups in sperm concentration or motility, or in levels of follicle-stimulating hormone, luteinizing hormone, or serum total testosterone. Also, sperm motion characteristics did not differ across the groups. Semen volume was the only semen variable which tended to decrease according to the number of cigarettes smoked. CONCLUSIONS Cigarette smoking had no apparent effect on sperm concentration, motility or reproductive hormonal levels, but tended to reduce semen volume. [source]