Susan Chinn — Page 2 | PubMed Health

PubMed2002

Comparing and combining studies of bronchial responsiveness.

BACKGROUND: There is no standardised protocol for the measurement of bronchial responsiveness. Results from different studies are difficult to compare and combine. METHODS: Analyses are divided between those of a continuous outcome, which can be directly standardised as effect size, and those based on a binary outcome. A published method is used to convert an odds ratio to equivalent effect size. RESULTS: The use of effect size allows comparison between studies using a continuous outcome but different protocols, provided the relevant standard deviation is reported. Effect size from a continuous outcome and that derived from an odds ratio from an equivalent analysis gave similar results. CONCLUSIONS: Systematic reviews which include both continuous effect estimates and odds ratios can include both in one meta-analysis, provided relevant standard deviations are published for the former. Authors are encouraged to report these in all fields in which measurement protocols vary.

Asthma↗

PubMedDate not supplied

Smoking cessation, lung function, and weight gain: a follow-up study.

BACKGROUND: Only one population-based study in one country has reported effects of smoking cessation and weight change on lung function, and none has reported the net effect. We estimated the net benefit of smoking cessation, and the independent effects of smoking and weight change on change in ventilatory lung function in the international European Community Respiratory Health Survey. METHODS: 6654 participants in 27 centres had lung function measured in 1991-93, when aged 20-44 years, and in 1998-2002. Smoking information was obtained from detailed questionnaires. Changes in lung function were analysed by change in smoking and weight, adjusted for age and height, in men and women separately and together with interaction terms. FINDINGS: Compared with those who had never smoked, decline in FEV1 was lower in male sustained quitters (mean difference 5.4 mL per year, 95% CI 1.7 to 9.1) and those who quit between surveys (2.5 mL, -1.9 to 7.0), and greater in smokers (-4.8 mL, -7.9 to -1.6). In women, estimates were 1.3 mL per year (-1.5 to 4.1), 2.8 mL (-0.8 to 6.3) and -5.1 mL (-7.5 to -2.8), respectively. These sex differences were not significant. FEV1 changed by -11.5 mL (-13.3 to -9.6) per kg weight gained in men, and by -3.7 mL per kg (-5.0 to -2.5) in women, which diminished the benefit of quitting by 38% in men, and by 17% in women. INTERPRETATION: Smoking cessation is beneficial for lung function, but maximum benefit needs control of weight gain, especially in men.

Adult↗