Aim

1. Estimated lung age in healthy Mediterranean adults cannot be predicted using reference equations derived from other populations Ben Saad H1,2, Elhraiech A2, Hadj Mabrouk K2, Maatoug C2, Rouatbi S1 1Department of Physiology and Functional Explorations. Farhat HACHED Hospital. 2Functional Exploration Laboratory. Occupational Medicine Group of Sousse. Tunisia. Rational Results Aim Conclusion Methods References Abbreviations Interpretation of “lung age” data relies upon comparison of the chronological lung age (CLA) with the estimated lung age (ELA) predicted from published reference equations: Morris and Temple1985, Newbury2010, Hansen2010, Yamaguchi2012 To test the applicability of the ELA published reference equations in healthy non-smokers Mediterranean aged 19-90 Yrs. The null hypothesis is that there will be no difference between CLA and ELA mean values. Bland and Altman representation, for the same age range as in the corresponding study, of CLA with ELA determined from reference equations of Morris and temple (fig A), Hansen et al. (fig B), Newbury et al. (fig C), Yamaguchi et al. (fig D). r: correlation coefficient; p: probability; n=number of subjects having the same age range as in the corresponding study.. : Mean; : mean ± 1.96±SD; : regression line. Design: cross sectional study. Sample size:n=(Z².p.q)/Δ². n (=455): needed number. Z: 95% confidence level (Z=1.96). p: prevalence of healthy non-smokers adult population aged more than 19 Yrs and free from disease, which is of the order of 60% in Tunisia. q=1-p=0.40. Δ:accuracy=4.5%. Inclusion criteria: healthy non-smokers and “normal” subjects aged 19-90 Yrs, having complete records with a technically acceptable and reproducible spirometry maneuvers. Collected data: CLA, sex, anthropometric (age, weight, height, body mass index) and spirometric (FVC, FEV1, PEF, MMEF, FEFx, FEV1/FVC) data and ELAs from the published reference equations. Spirometry function tests (Spida5; Micro Direct, Inc. 803 Webster Street Lewiston, ME 04240) according ATS/ERS-2005. Comparison of CLA vs. ELA: Student’s t-test andBland and Altman. The reference equation that provides the limits of agreement closest to zero will be the most appropriate for our population. Published and locally applied spirometric reference equations for ELA didn’t reliably predict CLA data in 540 adult’s healthy subjects representing a sample of a Mediterannean population. So, we can reject the null hypothesis that we would see no difference in the means of the CLA and ELA produced by the published reference equations. Our results strongly suggest that existing lung age equations are in need of review. Graphical comparison with published reference equations There was a systematic bias between the CLA and ELA values for all these equations; that is to say, the difference with CLA increased as the ELA increased. Morris J, Temple W. Spirometric “«lung age»” estimation for motivating smoking cessation. Prev Med 1985; 14:655-62. Newbury W et al. Exploring the need to update lung age equations Prim Care Respir J 2010; 19:242-7. Hansen JE et al. Calculating gambling odds and lung ages for smokers. Eur Respir J 2010; 35:776-80. Yamaguchi K et al. Novel regression equations predicting lung age from varied spirometric parameters. Respir Physiol Neurobiol 2012;183:108-14.. FEFx: forced expiratory flow when x% of FVC has been exhaled. FEV1: first second forced expiratory volume. FVC: forced vital capacity. LLN: lower-limit-of-normal. MMEF: maximal mid-expiratory flow. PEF: peak expiratory flow.