BACKGROUNDIn animal models, nutritional deficiency leads to profound qualitative changes in the lung beyond an effect on organ size. Although lung growth is non-isotropic, predictive values for spirometric lung function in children are corrected for height alone. Prediction of lung function should consider isotropic growth and nutritional status concurrently.
AIMTo establish whether nutritional status influences lung function following the exclusion of the effect of isotropic growth.
METHODSNutritional status (weight, body mass index, mid-upper arm circumference, and subscapular and triceps skinfold thicknesses) was assessed, and lung function (forced vital capacity (FVC), forced expiratory volume in one second (FEV₁), and peak expiratory flow rate (PEFR)) was measured in 391 healthy school age children with normal respiratory history and examination in a rural setting in West Bengal, India.
RESULTSLung function normalised for sitting height and stature correlated significantly with indices of nutrition in both sexes. Adding weight as an independent variable to sitting height, new reference prediction equations for FEV₁, FVC, and PEFR were calculated.
CONCLUSIONSNutritional differences influence qualitative aspects of lung development in childhood beyond simple isotropic lung growth. Prediction of lung function must take account of these differences if change as a result of disease is to be accurately measured. The identification and correction of relevant dietary deficiencies might help to improve lung function in children.

Keywords: lung development; lung function; nutrition; reference prediction equation