The effect of early growth patterns and lung function on the development of childhood asthma: a population based study

Background Infant weight gain is associated with lower lung function and a higher risk of childhood asthma. Detailed individual childhood growth patterns might be better predictors of childhood respiratory morbidity than the difference between two weight and height measurements. We assessed the associations of early childhood growth patterns with lung function and asthma at the age of 10 years and whether the child's current body mass index (BMI) influenced any association. Methods We derived peak height and weight growth velocity, BMI at adiposity peak, and age at adiposity peak from longitudinally measured weight and height data in the first 3 years of life of 4435 children enrolled in a population-based prospective cohort study. At 10 years of age, spirometry was performed and current asthma was assessed by questionnaire. Spirometry outcomes included forced vital capacity (FVC), forced expiratory volume in 1s (FEV1), FEV1/FVC ratio, and forced expiratory flow after exhaling 75% of vital capacity (FEF75). Results Greater peak weight velocity was associated with higher FVC but lower FEV1/FVC and FEF75. Greater BMI at adiposity peak was associated with higher FVC and FEV1 but lower FEV1/FVC and FEF75. Greater age at adiposity peak was associated with higher FVC, FEV1, FEV1/FVC and FEF75, particularly in children with a small size at birth, and lower odds of current asthma in boys. The child's current BMI only explained the associations of peak weight velocity and BMI at adiposity peak with FVC and FEV1. Peak height velocity was not consistently associated with impaired lung function or asthma. Conclusion Peak weight velocity and BMI at adiposity peak were associated with reduced airway patency in relation to lung volume, whereas age at adiposity peak was associated with higher lung function parameters and lower risk of asthma at 10 years, particularly in boys.