“…Lung function is known to vary with ethnicity, and it is therefore important to establish special reference values relevant to the ethnic group of the local population [5,6,7,8,9,10,11,12,13,14,15,16,17,18]. In contrast to genetic constitution, environmental factors affecting growth and development such as child health nutritional status and air quality may change over long periods of time [19], and therefore lung function values for a given ethnic community may change over time.…”