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Biomedical subjects

J E Connett

Publications and source records attributed to J E Connett.

At least 19 recordsLinked to original sources
PubMed1998

Early and late weight gain following smoking cessation in the Lung Health Study.

The authors examine weight gains associated with smoking cessation in the Lung Health Study (1986-1994) over a 5-year follow-up period. A cohort of 5,887 male and female smokers in the United States and Canada, aged 35-60 years, were randomized to either smoking intervention or usual care. Among participants who achieved sustained quitting for 5 years, women gained a mean of 5.2 (standard error, 5.0) kg in year 1 and a mean of 3.4 (standard error, 5.5) kg in years 1-5. Men gained a mean of 4.9 (standard error, 4.9) kg in year 1 and a mean of 2.6 (standard error, 5.8) kg in years 1-5. In regression analyses, smoking-change variables were the most potent predictors of weight change. Participants going from smoking to quit-smoking in a given year had mean weight gains of 2.95 kg/year (3.61%) in men and 3.09 kg/year (4.69%) in women. Over 5 years, 33% of sustained quitters gained > or = 10 kg compared with 6% of continuing smokers. Also among sustained quitters, 7.6% of men and 19.1% of women gained > or = 20% of baseline weight; 60% of the gain occurred in year 1, although significant weight gains continued through year 5. The average gains and the high proportions of sustained and intermittent quitters who gained excessive weight suggest the need for more effective early interventions that address both smoking cessation and weight control.

Adult↗
PubMed1998

High-frequency oscillation versus conventional ventilation following surfactant administration and partial liquid ventilation.

Surfactant followed by partial liquid ventilation (PLV) with perfluorocarbon (PFC; LiquiVent) improves oxygenation, lung compliance, and lung pathology in lung-injured animals receiving conventional ventilation (CV). In this study, we hypothesize that high-frequency oscillation (HFO) and CV will provide equivalent oxygenation in lung-injured animals following surfactant repletion and PLV, once lung volume is optimized. After saline-lavage lung injury during CV, newborn piglets were randomized to either HFO (n = 10) or CV (n = 9). HFO animals were stabilized over 15 min without optimization of lung volume; CV animals continued treatment with time-cycled, pressure-limited, volume-targeted ventilation. All animals then received 100 mg/kg of surfactant (Survanta). Thirty minutes later, all received intratracheal PFC to approximate functional residual capacity. Thirty minutes after PLV began, mean airway pressure (MAP) in both groups was increased to improve oxygenation. MAP was directly adjusted during HFO; PEEP and PIP were adjusted during IMV, maintaining a pressure sufficient to deliver 15 mL/kg tidal volume. Animals were treated for 4 h. The CV group showed improved oxygenation following surfactant administration (OI: 26.79 +/- 1.98 vs. 8.59 +/- 6.29, P < 0.0004), with little further improvement following PFC administration or adjustments in MAP. Oxygenation in HFO-treated animals did not improve following surfactant, but did improve following PFC (0I: 27.78 +/- 6.84 vs. 15.86 +/- 5.53, P < 0.005) and adjustments in MAP (OI: 15.86 +/- 5.53 vs. 8.96 +/- 2.18, P < 0.03). After MAP adjustments, there were no significant intergroup differences in oxygenation. Animals in the CV group required lower MAP than animals in the HFO group to maintain similar oxygenation. We conclude that surfactant repletion followed by PLV improves oxygenation during both CV and HFO. The initial response to administration of surfactant and PFC was different for the conventional and high-frequency oscillation groups, likely reflecting the ventilation strategy used; animals in the CV group responded most to surfactant, whereas animals in the HFO group responded most after PFC instillation. The ultimately similar oxygenation of the two groups once lung volume had been optimized suggests that HFO may be used effectively during administration of, and treatment with, surfactant and perfluorocarbon.

Animals↗
PubMed1998

Dynamics of spontaneous breathing during patient-triggered partial liquid ventilation.

This study evaluates different ventilator strategies during gas (GV) and partial liquid ventilation (PLV) in spontaneously breathing animals. We hypothesized that during PLV, spontaneously breathing animals would self-regulate respiratory parameters by increasing respiratory rate (RR) and minute ventilation (V'E) when compared to animals mechanically ventilated with gas, and further that full synchronization of each animal's effort to the ventilator cycle would decrease RR at stable tidal volumes (V(T)). We studied 12 newborn piglets (1.54 +/- 0.24 kg) undergoing GV and PLV in 3 different modes: intermittent mandatory ventilation (IMV), synchronized IMV (SIMV), and assist control ventilation (AC). Modes occurred sequentially in random order during GV first, with the same order then repeated during PLV. Animals initially received continuous positive airway pressure (CPAP) and returned to CPAP during PLV at the end of the experiment. Pressure-limited, volume-targeted ventilation was used with a tidal volume goal of 13 cc/kg. Rate was set at 10/min during IMV and SIMV, with a back-up rate of 10/min during AC. RR, V'E, mechanical (V(T)) and spontaneous tidal volumes (sV(T)) were measured breath-to-breath using a computer-assisted lung mechanics analyzer; mean values were determined over 30-min periods. Data analysis used paired t-tests with Bonferroni correction as needed (P < 0.05). Blood gases were stable in all modes during GV and PLV. RR (min(-1)) and V'E (L x min(-1)/kg) increased in all modes from GV to PLV (RR: CPAP 71 vs. 128; IMV 69 vs. 112; SIMV 65 vs. 107; AC 33 vs. 47. V'E: CPAP 0.47 vs. 0.72; IMV 0.46 vs. 0.61; SIMV 0.45 vs. 0.61; AC 0.38 vs. 0.53; P < 0.05). Intermode comparisons during PLV showed a lower RR with AC (P < 0.02), and a higher V'E with CPAP (P < 0.05). V(T) and dynamic respiratory system compliance decreased from GV to PLV (V(T) P < 0.05; C(rs,dyn) P < 0.01); sV(T) remained unchanged. V(T) and sV(T) did not differ in intermode comparisons. We conclude that during PLV, spontaneously breathing piglets with normal lungs maintain physiologic blood gases by increasing V'E through increased RR. AC produced the most efficient respiratory pattern during PLV, with increased V'E achieved by a modest increase in RR.

Animals↗
PubMed1998

Effect of weight gain on pulmonary function after smoking cessation in the Lung Health Study.

The objective of this study was to determine if the weight gain that accompanies smoking cessation is independently associated with reductions in FEV1 and FVC, using a multicenter randomized intervention trial of smoking cessation in 10 communities in the United States and Canada. Enrollees were currently smoking women and men 35 to 60 yr of age with mild-to-moderate airway obstruction. Participants were randomized to one of three study groups: an intensive smoking cessation program with an inhaled bronchodilator (or a placebo), and usual care. Changes in absolute and percent predicted FEV1 and FVC between baseline and fifth annual follow-up visit were monitored in relation to changes in body weight during the interval. At the baseline examination, percent predicted FEV1 was maximal at 90 to 100% ideal body weight (IBW) and was lower as body weight deviated from this range. The FVC decreased linearly when IBW exceeded 100%. Weight gain was greatest during the first 12 mo after smoking cessation. Weight gain was associated with lower fifth-year FEV1 and FVC in all smoking categories: continuous smokers, intermittent smokers, and sustained quitters. The FVC was affected by weight gain more than was the FEV1, and the FEV1 was affected by smoking cessation more than FVC. Men showed more impairment of FVC with weight gain than did women, possibly because of differential patterns of fat deposition. In sustained quitters, after adjustment for baseline factors, the estimated reduction of FVC was 17.4 ml/kg weight gain for men and 10.6 ml/kg for women. The estimated loss of FEV1 was 11.1 ml/kg weight gain for men and 5.6 ml/kg for women. Lung function after smoking cessation is significantly influenced by weight gain and affects men more than women. The deleterious effects of weight gain are small, however, in comparison with the beneficial effects of smoking cessation.

Adipose Tissue↗
PubMed1997

Partial liquid ventilation: a comparison using conventional and high-frequency techniques in an animal model of acute respiratory failure.

OBJECTIVE: To test the hypothesis that high-frequency ventilation (HFV), when compared with conventional techniques, enhances respiratory gas exchange during partial liquid ventilation (PLV). DESIGN: A four-period crossover design. SETTING: Animal research laboratory of Children's Health Care-St. Paul. SUBJECTS: Thirty-two newborn piglets, weighing 1.40 +/- 0.39 kg. INTERVENTIONS: Animals were divided into four groups of eight animals: a) PLV with high-frequency jet ventilation; b) PLV with jet ventilation using a background intermittent mandatory ventilation (IMV) rate; c) PLV with high-frequency oscillation; or d) PLV with high-frequency flow interruption using a background IMV rate. After anesthesia, paralysis, and tracheotomy, a normal saline wash procedure produced lung injury. Perfluorocarbon was then instilled via the endotracheal tube in an amount estimated to represent functional residual capacity. Animals received randomly either PLV using conventional techniques or PLV using the selected HFV technique as initial treatment. Then, animals were crossed over to the alternative treatment at equal mean airway pressure, as measured at the endotracheal tube tip. This sequence was repeated for a total of four crossover periods, such that all animals were treated twice with PLV using conventional techniques and twice with PLV using HFV. MEASUREMENTS AND MAIN RESULTS: We measured airway pressures at the endotracheal tube tip, aortic and central venous blood pressures, arterial blood gases, and respiratory system mechanics at baseline, after induction of lung injury, and at specified intervals throughout the experiment. Measurements were made before and 15 mins after crossovers, then ventilators were adjusted to normalize gas exchange. Measurements were again made 30 mins later, at the end of the treatment period. All types of PLV provided adequate gas exchange. Only PLV using jet ventilation with IMV produced gas exchange equal to that seen during PLV using conventional techniques at equivalent mean airway pressure. By the end of the treatment periods, only PLV using high-frequency oscillation continued to require higher airway pressure than PLV using conventional techniques for equivalent gas exchange. CONCLUSIONS: Gas exchange was not enhanced during PLV-HFV. Application of HFV with PLV provides no clear acute physiologic advantages to PLV using more conventional techniques.

Animals↗
PubMed1997

Prolonged partial liquid ventilation using conventional and high-frequency ventilatory techniques: gas exchange and lung pathology in an animal model of respiratory distress syndrome.

OBJECTIVE: To evaluate the effect of prolonged partial liquid ventilation with perflubron (partial liquid ventilation), using conventional and high-frequency ventilatory techniques, on gas exchange, hemodynamics, and lung pathology in an animal model of lung injury. DESIGN: Prospective, randomized, controlled study. SETTING: Animal laboratory of the Infant Pulmonary Research Center, Children's Health Care-St. Paul. SUBJECTS: Thirty-six newborn piglets. INTERVENTIONS: We studied newborn piglets with lung injury induced by saline lavage. Animals were randomized into one of five treatment groups: a) conventional gas ventilation (n = 8); b) partial liquid ventilation with conventional ventilation (n = 7); c) partial liquid ventilation with high-frequency jet ventilation (n = 7); d) partial liquid ventilation with high-frequency oscillation (n = 7); and e) partial liquid ventilation with high-frequency flow interruption (n = 7). After induction of lung injury, all partial liquid ventilation animals received intratracheal perflubron to approximate functional residual capacity. After 30 mins of stabilization, animals randomized to high-frequency ventilation were changed to their respective high-frequency modes. Hemodynamics and blood gases were measured before and after lung injury, after perflubron administration, and then every 4 hrs for 20 hrs. Histopathologic evaluation was carried out using semiquantitative scoring and computer-assisted morphometric analysis on pulmonary tissue from animals surviving at least 16 hrs. MEASUREMENTS AND MAIN RESULTS: All animals developed acidosis and hypoxemia after lung injury. Oxygenation significantly (p < .001) improved after perflubron administration in all partial liquid ventilation groups. After 4 hrs, oxygenation was similar in all ventilator groups. The partial liquid ventilation-jet ventilation group had the highest pH; intergroup differences were seen at 16 and 20 hrs (p < .05). The partial liquid ventilation-oscillation group required higher mean airway pressure; intergroup differences were significant at 4 and 8 hrs (p < .05). Aortic pressures, central venous pressures, and heart rates were not different at any time point. Survival rate was significantly lower in the partial liquid ventilation-flow interruption group (p < .05). All partial liquid ventilation-treated animals had less lung injury compared with gas-ventilated animals by both histologic and morphometric analysis (p < .05). The lower lobes of all partial liquid ventilation-treated animals demonstrated less damage than the upper lobes, although scores reached significance (p < .05) only in the partial liquid ventilation-conventional ventilation animals. CONCLUSIONS: In this animal model, partial liquid ventilation using conventional or high-frequency ventilation provided rapid and sustained improvements in oxygenation without adverse hemodynamic consequences. Animals treated with partial liquid ventilation-flow interruption had a significantly decreased survival rate vs. animals treated with the other studied techniques. Histopathologic and morphometric analysis showed significantly less injury in the lower lobes of lungs from animals treated with partial liquid ventilation. High-frequency ventilation techniques did not further improve pathologic outcome.

Animals↗
PubMed1997

Exogenous surfactant and partial liquid ventilation: physiologic and pathologic effects.

We compared the effects of surfactant and partial liquid ventilation (PLV), and the impact of administration order, on oxygenation, respiratory system compliance (Crs), hemodynamics, and lung pathology in an animal lung injury model. We studied four groups: surfactant alone (S; n = 8); partial liquid ventilation alone (PLV-only; n = 8); surfactant followed by partial liquid ventilation (S-PLV; n = 8); and partial liquid ventilation-followed by surfactant (PLV-S; n = 8). Following treatments, all animals had improved oxygenation index (OI) and Crs. Animals in PLV groups showed continued improvement over 2 h (% change OI: PLV-S -83% versus S -47%, p < 0.05; % change Crs: S-PLV 73% versus S 13%, p < 0.05). We also saw administration-order effects: surfactant before PLV improved Crs (0.92 ml/cm H2O after surfactant versus 1.13 ml/cm H2O after PLV, p < 0.02) without changing OI, whereas surfactant after PLV did not change Crs and OI increased (5.01 after PLV versus 8.92 after surfactant, p < 0.03). Hemodynamics were not different between groups. Pathologic analysis demonstrated decreased lung injury in dependent lobes of all PLV-treated animals, and in all lobes of S-PLV animals, when compared with the lobes of the S animals (p < 0.05). We conclude that surfactant therapy in combination with PLV improved oxygenation, respiratory system mechanics, and lung pathology to a greater degree than surfactant therapy alone. Administration order affected initial physiologic response and ultimate pathology: surfactant given before PLV produced the greatest improvements in pathologic outcomes.

Animals↗
PubMed1996

The one-year surgical outcome after prism adaptation for the management of acquired esotropia.

PURPOSE: To report the 1-year motor and sensory outcomes for patients with acquired comitant esotropia managed with preoperative prism adaptation. METHODS: Patients entered a multicenter randomized prospective evaluation of prism adaptation before strabismus surgery. Prism responders were randomized to surgery with the target angle based on either the entry angle or the adapted angle of esotropia. Three hundred five patients (92 percent of cohort) completed 1-year postoperative follow-up. RESULTS: The overall motor success rate for all patients in the study was 74 percent. Prism responders operated on for the adapted esotropic target angle had a satisfactory motor outcome more often than those operated on for the entry angle, 90 percent compared with 75 percent (P = 0.04). Significant predictors of a satisfactory motor outcome after surgery were prism adaptation, female sex, and hyperopia greater than or equal to +3.00 D. Prism responders operated on for the adapted angle showed fusion of the Worth 4-dot at substantially more often than did those operated on for the entry angle, 75 percent compared with 60 percent (P = 0.12). CONCLUSION: Prism adaptation significantly improves the 1-year motor outcome after esotropia surgery in prism responders. There is no increase in the number of overcorrections. These results confirm the value of allotting the extra time and potential expense needed for this technique.

Adaptation, Ocular↗
PubMed1996

Methacholine reactivity predicts changes in lung function over time in smokers with early chronic obstructive pulmonary disease. The Lung Health Study Research Group.

As part of a clinical trial of early intervention in chronic obstructive pulmonary disease (COPD) (the Lung Health Study), 5,733 smokers with mild to moderate airflow obstruction underwent methacholine challenge tests at baseline. All participants were randomized to receive either usual care (no intervention) or special intervention, consisting of intensive smoking cessation counseling and the prescription of a metered-dose inhaler containing either ipratropium bromide or placebo (two inhalations three times daily). For this report, we analyzed the relationship between baseline methacholine reactivity and subsequent change in lung function. Methacholine reactivity was expressed as a logarithmic function of the two-point slope of percent decline in FEV1 over the concentration of methacholine (LMCR). Using a random effects linear model, LMCR was found to be a strong predictor of change in FEV1% predicted, after controlling for baseline lung function, age, sex, baseline smoking history, and changes in smoking status. Significant interactions were found between reactivity and smoking behavior. In the first year, participants who quit smoking showed improvement in FEV1, whereas continuing smokers showed worsening, and between Years 1 and 5, lung function declined to a greater extent in continuing smokers than in sustained quitters. For both time periods, these quitter/smoker differences increased as a function of airway reactivity. These findings indicate that methacholine reactivity is an important predictor of progression of airway obstruction in continuing smokers with early COPD, independent of the baseline level of obstruct.

Bronchoconstrictor Agents↗
PubMed1996

Safety of nicotine polacrilex gum used by 3,094 participants in the Lung Health Study. Lung Health Study Research Group.

STUDY OBJECTIVE: To assess cardiovascular conditions and other side effects associated with the use of nicotine polacrilex (NP), 2 mg. DESIGN: A multicentered randomized control trial of early intervention for the prevention of COPD. SETTING: Ten university medical centers in the United States and Canada. PARTICIPANTS: Adult smoking volunteers with evidence of early COPD; 3,923 in intervention and 1,964 controls. INTERVENTION: Smoking cessation program, including NP. MEASUREMENTS: Data on hospitalizations were collected annually. Data on reported NP side effects were collected at 4-month intervals for intervention participants. RESULTS: The rates of hospitalization for cardiovascular conditions and cardiovascular deaths during the 5 years of the study were not related to use of NP, to dose of NP, or to concomitant use of NP and cigarettes. About 25% of NP users reported at least one side effect, but most were very minor and transient. Side effects associated with discontinuance of NP in 5% or more of users included headache, indigestion, mouth irritation, mouth ulcers, and nausea. There was no evidence that concomitant use of NP and cigarettes was associated with elevated rates of reported side effects. Participants in the smoking cessation intervention who received intensive levels of instruction and monitoring of NP use (initially at 12 meetings during 3 months) appeared to report significantly lower rates of side effects (dizziness, headache, and throat irritation) than control participants, presumed to have less instruction and monitoring. CONCLUSIONS: NP, as used in the Lung Health Study, appears to be safe and unrelated to any cardiovascular illnesses or other serous side effects.

Adult↗
PubMed1995

Predictors of initial smoking cessation and relapse through the first 2 years of the Lung Health Study.

Analyses were made separately for men and women of the predictors of end-of-treatment (4 months) smoking cessation and subsequent relapse at 12 and 24 months among 3,923 participants enrolled in the Lung Health Study's 12-week cognitive-behavioral group smoking cessation program. Nicotine gum (2 mg) was available to all participants. Men were more likely than women to quit smoking initially, but relapse rates were similar for both genders. Baseline variables associated with initial quitting for both genders included greater education, lower nicotine dependence, and fewer respiratory symptoms. The best predictor of relapse between 4 and 12 months was smoking at least 1 cigarette between quit day and 4 months. Nicotine gum use at 12 months predicted relapse by 24 months for both genders. Greater social and environmental support for quitting smoking were the only factors that predicted both initial quitting and relapse for both genders. Clinical implications are discussed.

Adult↗
PubMed1995

Spirometry in the Lung Health Study: II. Determinants of short-term intraindividual variability.

The Lung Health Study (LHS) is a randomized clinical trial designed to determine whether a smoking intervention program and use of an inhaled bronchodilator (BD) can reduce the rate of decline of FEV1 in cigarette smokers with airflow limitation. During recruitment, spirometry was performed at second and third screening visits, a mean of 21 d apart. A total of 5,887 smokers, 35 to 60 yr of age and of whom 63% were men, met the study eligibility requirements. Smokers taking physician-prescribed BDs or with an FEV1 < 50% or > 90% predicted were excluded, as were those whose FEV1/FVC ratio was greater than 70%. Two inhalations of isoproterenol were given to determine BD response during the second visit. A serial dilution methacholine challenge test was done during the third visit to determine nonspecific airway reactivity. Ninety-five percent of the differences between FEV1 measured at the two visits were within 240 ml for women and within 320 ml for men (coefficients of repeatability). The best independent predictors of the mean short-term (between visit) intraindividual FEV1 variability were factors indicating intrinsic airway reactivity of the participants: bronchodilator response, methacholine reactivity, and the presence of wheezing; as well as factors influenced by the quality of spirometry testing: the difference between the highest and second highest FEV1s and peak flows during baseline spirometry, and the time to reach peak flow (PEFT).

Adult↗
PubMed1995

Gender differences in smoking cessation after 3 years in the Lung Health Study.

OBJECTIVES: An analysis of gender differences in smoking cessation was conducted among 3923 participants in the Special Intervention group of the Lung Health Study. This report focuses on gender differences in sustained quit rates at 12 and 36 months. METHODS: Special Intervention participants were offered a 12-session, 12-week smoking cessation program using nicotine gum and were followed for 3 years. Self-reported smoking status was validated with carbon monoxide and salivary cotinine. RESULTS: Men had higher sustained quit rates at 12 and 36 months; gender differences were found in baseline variables that also predicted sustained abstinence; and controlling for selected baseline variables reduced the association between gender and sustained abstinence. When other variables were controlled, gender predicted sustained abstinence at 36 months (odds ratio [OR] = 1.24, 95% confidence interval [CI] = 1.04, 1.48) but not 12 months (OR = 1.08, 95% CI = 0.92, 1.27), reflecting more late relapse among women. CONCLUSIONS: Demographics and smoking history were more important than gender per se in sustained smoking cessation in the Lung Health Study. Programs tailoring smoking cessation by gender need to include coping skills for problems associated with less education and social support and for improving persistence with quit attempts.

Adult↗
PubMed1994

Effects of smoking intervention and the use of an inhaled anticholinergic bronchodilator on the rate of decline of FEV1. The Lung Health Study.

OBJECTIVE: To determine whether a program incorporating smoking intervention and use of an inhaled bronchodilator can slow the rate of decline in forced expiratory volume in 1 second (FEV1) in smokers aged 35 to 60 years who have mild obstructive pulmonary disease. DESIGN: Randomized clinical trial. Participants randomized with equal probability to one of the following groups: (1) smoking intervention plus bronchodilator, (2) smoking intervention plus placebo, or (3) no intervention. SETTING: Ten clinical centers in the United States and Canada. PARTICIPANTS: A total of 5887 male and female smokers, aged 35 to 60 years, with spirometric signs of early chronic obstructive pulmonary disease. INTERVENTIONS: Smoking intervention: intensive 12-session smoking cessation program combining behavior modification and use of nicotine gum, with continuing 5-year maintenance program to minimize relapse. Bronchodilator: ipratropium bromide prescribed three times daily (two puffs per time) from a metered-dose inhaler. MAIN OUTCOME MEASURES: Rate of change and cumulative change in FEV1 over a 5-year period. RESULTS: Participants in the two smoking intervention groups showed significantly smaller declines in FEV1 than did those in the control group. Most of this difference occurred during the first year following entry into the study and was attributable to smoking cessation, with those who achieved sustained smoking cessation experiencing the largest benefit. The small noncumulative benefit associated with use of the active bronchodilator vanished after the bronchodilator was discontinued at the end of the study. CONCLUSIONS: An aggressive smoking intervention program significantly reduces the age-related decline in FEV1 in middle-aged smokers with mild airways obstruction. Use of an inhaled anticholinergic bronchodilator results in a relatively small improvement in FEV1 that appears to be reversed after the drug is discontinued. Use of the bronchodilator did not influence the long-term decline of FEV1.

Administration, Inhalation↗
PubMed1994

Use of surrogate information time for monitoring the effect of treatment on the change in a response variable in clinical trials.

We discuss the monitoring of clinical trials data and propose two surrogates for total information for use with the spending function approach where there are repeated measurements and we wish to compare the rates of change in a response variable under different treatments. These surrogates are applied to a setting similar to the Lung Health Study. Although the surrogates do not require estimation of the variance parameters, they do require some knowledge of the ratio R of the within- to the between-individual variances. The effects of overestimating and underestimating R are illustrated. In situations of uncertainty we recommend overestimating R, to provide a conservative estimate of information time at each interim analysis.

Adult↗
PubMed1994

Gender difference in airway hyperresponsiveness in smokers with mild COPD. The Lung Health Study.

Methacholine bronchoprovocation challenge testing was successfully completed in 5,662 participants (3,556 men and 2,106 women) at the time they were randomized into the Lung Health Study, a multicenter trial designed to evaluate early intervention in chronic obstructive pulmonary disease (COPD). All participants were smokers between the ages of 35 and 60 yr who had mild COPD. The male:female prevalence of a positive challenge (PC20FEV1) was 25%:48% and 63%:87% at a PC20FEV1 of < or = 5 mg/ml (AHR5) and < or = 25 mg/ml (AHR25), respectively. This analysis explores these marked gender differences in airway hyperresponsiveness (AHR). Relative risks (RR) for predictors of AHR and the 95% confidence intervals (95% CI) were estimated using semiparametric Cox proportional-hazards models. The initial model controlled for age, gender, smoking history, height, and weight. The RR (95% CI) for female gender was 1.75 (1.60, 1.92). When the measured baseline FEV1 was added to the model as a surrogate for airway caliber, the RR for female gender decreased to 1.06 (0.96, 1.18). Thus, in this population of middle-aged smokers with mild COPD, the high prevalence of AHR appears to be associated with a decrease in airway caliber. The higher prevalence of AHR noted in women is due to their having a smaller airway caliber than their male counterparts.

Adult↗
PubMed1993

Design and results of the initial intervention program for the Lung Health Study. The Lung Health Study Research Group.

BACKGROUND: The design and results of the initial intervention program of the Lung Health Study are presented for 3,923 male and female participants. One of the major aims of this clinical trial was to achieve smoking cessation early in the study and to provide intensive follow-up procedures for maintaining abstinence. In addition, compliance with use of aerosolized inhalers (either placebo or active bronchodilator) would be necessary in order to achieve the trial goal of improved pulmonary function. RESULTS: Eighty-eight percent of the special intervention participants attended the 4-month follow-up visit. Forty-six percent reported not smoking from quit day through the visit, and an additional 13% had stopped smoking at the end of 4 months, although they had not achieved abstinence since quit day. The aerosol inhaler compliance was self-reported at 81% at the 4-month visit. Validating the self-reports by weighing canisters reduced the "good" compliance rates to 66%. CONCLUSIONS: The intensive behavioral program was effective in achieving high initial rates of smoking cessation and inhaler compliance. Use of nicotine gum appeared to be an effective adjunct to the multicomponent behavioral program. Smoking status does appear to be related to inhaler compliance among both men and women participants.

Administration, Inhalation↗