Background and objective: Ethnic-specific reference equations are recommended when performing spirometry. In the absence of appropriate reference equations for Australian Aboriginal and/or Torres Strait Islanders (Indigenous), we determined whether any of the existing Global Lung Function Initiative (GLI)-2012 equations were suitable for use in Indigenous children/young adults.
Methods: We performed spirometry on 1278 participants (3–25 years) who were identified as Aboriginal, Torres Strait Islander or ‘both’. Questionnaires and medical records were used to identify ‘healthy’ participants. GLI2012_DataConversion software was used to apply the ‘Caucasian’, ‘African-American’ and ‘other/mixed’ equations.
Results: We included 930 healthy participants. Mean z-scores for forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) were lower than the Caucasian predicted values (range: −0.53 to −0.60) and higher than African-American (range: 0.70 to 0.78) but similar to other/mixed (range: 0.00 to 0.08). The distribution of healthy participants around the upper and lower limits of normal (~5%) fit well for the other/mixed equation compared to the Caucasian and African-American equations.
Conclusion: Of the available GLI-2012 reference equations, the other/mixed reference equation provides the best overall fit for Indigenous Australian children and young adults (3–25 years). Healthy data from additional communities and adults around Australia will be required to confirm generalizability of findings.