The aim of this study was to derive new spirometric reference equations for the English population, using the 1995/1996 Health Survey for England, a large nationally representative cross-sectional study.The measurements used were the forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) of a sample of 6,053 "healthy" (nonsmokers with no reported diagnosis of asthma or respiratory symptoms) White people aged o16 yrs. Multiple regression analysis, with age and height as predictors, was carried out to estimate prediction equations for mean FEV1, FVC and FEV1/FVC, separately for males and females. A method based on smoothing multiple estimates of the fifth percentiles of residuals was used to derive prediction equations for the lower limit of normal lung function.The new equations fit the current English adult population considerably better than the European Coal and Steel Community equations, and the proportions of people with "low" (below the fifth percentile) lung function are closer to those expected throughout the whole adult age range (16 to w75 yrs). For the age ranges the studies share in common, the new equations give estimates close to those derived from other nonlinear equations in recent studies.It is, therefore, suggested that these newly developed prediction equations be used for the White English population in both epidemiological studies and clinical practice. Reference values, predicted for normal healthy nonsmokers, are generally used in epidemiological work as well as in clinical surveillance to determine low lung function and assess the effect of environmental exposure. A number of sets of prediction equations are currently available for different populations, with those most widely used based on relatively old studies [1][2][3][4].In 1995 and 1996, the general population Health Survey for England (HSE) had a focus on respiratory disease, and the lung function of respondents was measured. Use of European Coal and Steel Community (ECSC) reference values [4] for analysis in the published reports showed that these values were not predictive of normal lung function for the English population [5]. This poor fit for the ECSC reference values prompted the present study, to derive a new set of reference values based on the HSE 1995 and 1996 combined datasets. These newly derived reference values are presented here and compared with the ECSC and other recent reference values. MethodsThe design of the HSE, an annual nationwide household survey of the English population, has been described in detail elsewhere [6]. Briefly, members of a stratified random sample, sociodemographically representative of the English population, were invited to participate in 1995 and 1996. The mean response rate was w75% in both years, but slightly lower than average amongst males and in inner cities. Data on each respondent were collected during two visits, with identical methods used in 1995 and 1996: an interviewer9s visit, during which a questionnaire was administered and height and weight m...

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