The effect of ethnic origin on pulmonary prediction equations in a Jewish immigrant population

Background: Ethnic origin affects spirometric prediction values. Our aims were to investigate the effect of ethnic origin on prediction equations in an immigrant-based society, identify possible deviations from commonly used prediction equations and analyze the effect of miscalculation in a large cohort of apparently healthy individuals. Methods: Healthy never-smokers participants from a large Israeli survey underwent lung function testing and were divided into two major ethnic groups: Ashkenazi Jews (AJ) and Sephardic Jews (SJ). Data were analyzed by multiple linear regressions. Forced vital capacity (FVC), forced expiratory volume in 1 s (FEV₁) and the FEV₁/FVC ratio were measured according to ERS-ATS guidelines. Results: The study population comprised 3150 individuals (AJ=1817; SJ=1333). AJ tended to be older and taller than SJ (all p<0.005). Ethnicity entered as a significant regression variable for FVC for both genders and for FEV₁ for females only. The final regression model for both FVC and FEV₁ had R²=0.71 and the standard error of the estimate (SEE) for FVC and FEV₁ were 0.54 and 0.43 L, respectively. The regression model for the FEV₁/FVC ratio has less statistical strength (R²=0.06, SEE=6.15%). We found statistically significant underestimates of predicted lung volumes from the commonly used prediction equation for each ethnic group. Conclusions: Ashkenazi and Sephardic Jews have different ranges of normal pulmonary function values. Lung function prediction equations in an immigrant-based society should be based on local and not previously reported regional equations and adjusted for ethnic attributed variance.