Lung function reference equations and lower limit of normal for Cree First Nations Children and adolescents living in rural Saskatchewan,Canada

Abstract

BACKGROUND:

Spirometric prediction equations are used to evaluate lung function in the clinical setting. However, such equations are not yet available for First Nations populations. The purpose of this study is to derive appropriate spirometric reference equations for a group of Cree First Nations school-aged children and adolescents living in rural Saskatchewan, Canada.

METHODS:

Spirometric data was collected from Cree First Nations cohort living in rural Saskatchewan, Canada. In the baseline survey, 351 children and adolescents participated and of these 134 were identified as healthy non-smoking individuals. The predicted values and Lower Limit of Normal (LLN) of spirometric indices were calculated for school-going children and adolescents (ages 6–17 years for males and 6–14 years for females). The spirometric indices were assumed to follow a Box-Cox-Cole-Green (BCCG) distribution with median, $\mu$ , coefficient of variation, ${\sigma }_L$ and skewness, $\nu$ . Akaike Information Criteria (AIC) approach was used to obtain the reference models. The LLN was calculated by taking the fifth percentile of the prediction equations of the lung function variables.

RESULTS:

Two-sample $t$ -test revealed significant differences in the means of lung function and demographic measurements between both boys and girls. Therefore, separate equations were fitted for both boys and girls.

CONCLUSION:

This study provides the baseline lung function reference equations for Cree First Nations children and adolescents. This baseline study provides a platform for future studies, which can be conducted to improve the accuracy of the predicted lung function indices for such study cohort.