Reference equations for lung function screening of healthy never-smoking adults aged 18–80 years

Abstract

The need for updated spirometric reference values to be used on European populations is widely acknowledged, especially for subjects aged .70 yrs. Their reference values are generally based on extrapolations. The aim of the present study was to calculate reference values for lung function screening of healthy, never-smoking adults aged 18-80 yrs and to compare them with the most widely used reference equations.Results of screening spirometry of 8,684 healthy, never-smoking adults were used to calculate mean values and fifth percentiles of lung function variables.The European Community of Coal and Steel (ECCS) reference equations underestimate forced expiratory volume in one second (FEV1) and forced vital capacity (FVC). For example, in 50-yr-old males (height 175 cm), lower limits of normal for FEV1 are underestimated by 198 mL, and for FVC by 210 mL. In 50-yr-old females (height 165 cm), lower limits of normal for FEV1 are underestimated by 191 mL, and for FVC by 270 mL. The decline of FVC in elderly subjects is steeper than predicted by the ECCS.Reference equations derived from spirometry data locally collected in a practical setting by well-trained personnel might be more appropriate for everyday use than generally used equations based on data from scientific studies in the distant past.

Alternative ways of expressing FEV1and mortality in elderly people with and without COPD

“…For example, it has been shown that the commonly used equations proposed by the European Respiratory Society/ European Community of Coal and Steel [15] underestimate the FEV1 compared to other reference equations [16]; as a result, these equations would classify as ''normal'' people that would be classified as having a reduction of pulmonary function using other equations. Another problem with the use of reference equations is that the coefficient of variation is age-dependent, and in adults increases considerably with age [3].…”

Reference values for lung function: past, present and future

“…However, the abundance of unrelated studies can introduce new complexities, not least because most are not generalisable to any other population than the one in which they were collected. Two exceptions to this were the Health Survey for England [32], which studied a large population (6,053 individuals) and included subjects from 16-90 yrs [31], and the recently published study by KUSTER et al [35] which was also based on a very large sample (8, predicted values as well as bias, particularly in elderly subjects who tend to overestimate their current height. Both of these studies were limited to older subjects, thereby excluding the complexities of puberty and growth spurts.…”

“…There is a relative lack of reference data for elderly subjects [35], with existing data based on relatively small and unrepresentative samples. Most of the currently recommended reference equations were developed in the 1980s and 1990s such that the older participants would be those born at the beginning of the 20th Century, with potential for cohort effects due to changes in health, nutrition and measurement standards [44].…”

“…The tendency for over-estimated, self-reported height in the elderly may add further bias. Recent studies, such as those by FALASCHETTI et al [34] and KUSTER et al [35], are particularly important as they can provide more appropriate reference equations for current generations. As lung function is highly age dependent in adults, future studies should aim to include a larger number of older subjects to improve the accuracy with which we can interpret spirometry in this population.…”

Diagnosis of Chronic Obstructive Pulmonary Disease with Special Reference to Over- and Underdiagnosis Using Spirometry

“…the prediction equations for Caucasian adult males and females derived from the Third US National Health and Nutrition Examination Survey (NHANES-III) (Hankinson et al, 1999) Brändli et al have published reference values of a Swiss population (Brädli et al, 1996;Brädli et al, 2000). In 2001 Langhammer et al published forced spirometry reference values for Norwegian adults (Langhammar et al, 2001) Recently Kuster et al published another set of reference equations for lung function of never smoking Swiss adults aged 18-80 years (Kuster et al, 2008). Falaschetti et al have published reference values predicted for an English adult population using data from the 1995/1996 Health Survey for England (Falaschetti et al, 2004).…”