Is respiratory function diminished?
An association between diminished respiratory function and an environmental agent should reflect the magnitude of the exposure and not be due to technical error, bias, confounding factors, or chance. Bias is difficult to avoid; the best course is to make comparisons within a population of exposed individuals, not between them and a control group; the population should be defined and a high response rate achieved. The principal confounding factors are age, smoking, and other environmental exposures; their effects should be fully estimated for the population in question as otherwise they will be wrongly attributed to the environmental agent. Finally, the results should be scrutinized and, if possible, a second independent study should be planned.
Cotes
J E
JE
Respiration and Exercise Laboratory, University of Newcastle upon Tyne, England.
Chinn
D J
DJ
D003430:Cross-Sectional Studies; D004781:Environmental Exposure; D006801:Humans; D008137:Longitudinal Studies; D008168:Lung / Q000503:physiopathology*; D008171:Lung Diseases / Q000453:epidemiology* / Q000503:physiopathology; D008176:Lung Volume Measurements; D011786:Quality Control; D012016:Reference Values; D012907:Smoking / Q000009:adverse effects