Ethnic variation in childhood lung function may relate to preventable nutritional deficiency

This study aimed to define the differences in lung function between British Caucasian and rural eastern Indian children, and to test the hypothesis that nutrition could account for such "ethnic" variation. To exclude confounders, a rural Indian setting was identified and children were screened for respiratory illness before lung function and nutritional characteristics were measured. Regression equations for this population have already been published. In this study, the lung function differences between rural eastern Indian (n=391) and mean predicted lung function for Caucasian children were characterized, matched for height and sex. In addition, stepwise multiple regression models were fitted to investigate the relative associations of lung function differences with body mass index (BMI), occipitofrontal circumference and age. Although the largest differences in the forced expiratory volume in 1 s (FEV1) [girls 28.7 (27.3-30.1), boys 23.4 (22.2-24.6)] and forced vital capacity [girls 27.9 (26.4-29.4), boys 30.7 (29.6-31.9)] [values as mean difference in % predicted (95% confidence intervals)] ever reported between two populations were observed, differences in peak expiratory flow rate (PEFR) were small. BMI was strongly associated with inter-racial differences for FEV1 for both sexes (boys beta = -0.227, girls beta = -0.353. p < 0.001) and PEFR for girls (beta = -0.200, p < or = 0.05) (beta = standardized coefficient). Preventable nutritional factors may play a causal role in determining the FEV1 differences between rural Indian and Caucasian children. As peak FEV1 in youth influences respiratory morbidity in later life, it is important to define specific nutrient deficiencies that may relate to poor FEV1 growth in these children.