Fetal and infant growth patterns and risk of lower lung function and asthma

Rationale: Children with lower birth weight are at increased risk of asthma symptoms.
Objectives: To examine associations of fetal and infant growth with childhood lung function and asthma.
Methods: This study was embedded in a population-based prospective cohort study of 5, 635 children. Growth was estimated by repeated ultrasounds in the second and third trimesters, and measured at birth and at 3, 6, and 12 months. At age 10 years, spirometry was performed and asthma was assessed by parental questionnaire. Restricted and accelerated growth were defined as the growth percentile change between time periods less than 20.67 and more than 0.67 SD scores (SDSs), respectively. We applied multiple regression analyses, including conditional regression analyses, to account for correlations between repeated growth measures.
Measurements and Main Results: Overall greater weight in the second and third trimesters, at birth, and at 12 months was associated with higher FEV1 and FVC (range of z-score difference, 0.04-0.08, per SDS increase in weight). Greater weight at 3 months was associated with lower FEV1/FVC and forced expiratory flow at 75% of the pulmonary volume (FEF75%) (z-score differences [95% confidence interval]: 20.09 [20.14 to 20.05] and 20.09 [20.13 to 20.05] per SDS increase in weight, respectively). Restricted fetal weight growth was associated with lower childhood lung-function measures, partly depending on infant weight growth patterns (range of z-score difference, 20.25 to 20.13). Accelerated fetal weight growth was associated with higher FVC and lower FEV1/FVC only if followed by accelerated infant weight growth. Fetal and infant weight growth was not associated with childhood asthma.
Conclusions: Both restricted fetal weight growth, partly depending on infant weight growth, and accelerated fetal and infant weight growth predispose children to lower lung function and a potential risk for respiratory diseases later in life.