Children with mild BPD exhibited similar impairments in respiratory mechanics and lung structure to those diagnosed with moderate BPD. The widespread involvement of the peripheral airways suggests that all children diagnosed with BPD are potentially at risk of developing chronic obstructive pulmonary disease later in life.

Exposure to traffic-related air pollution in infancy is negatively associated with FEV1 at age 16 years, leading to increased risk of clinically important deficits.

Background and objectives: Follow-up studies of children and young adults born very-

BACKGROUND AND OBJECTIVE: Knowledge regarding lung function after moderately preterm birth is limited. We therefore investigated lung function at early school age and adolescence among children born moderately preterm.

In the present study BPD severity did not predict lung function, but may be associated with impaired alveolarization, indicated by reduced Cso . Respiratory morbidity was associated with reduced airway function and respiratory compliance in infancy after preterm birth.

All asthma phenotypes studied were negatively associated with FEV1 in adolescence. IOS measurements indicated that active asthma could be associated with small airway impairments. These results provide new insights into the physiology underlying wheezing phenotypes based on age of onset and duration of disease.

In summary, rather few exposures in childhood were identified to have a significant impact on lung function growth between childhood and adolescence. Our data support previous study findings indicating that lung function development is influenced by factors before birth and in infancy, including second hand tobacco smoke.

Maternal smoking during pregnancy is associated with impaired lung function among young children, but less is known about long-term effects and the impact of adolescents' own smoking. We investigated the influence of maternal smoking during pregnancy, secondhand smoke exposure and adolescent smoking on lung function at age 16 years.The BAMSE (Barn/Child, Allergy, Milieu, Stockholm, Epidemiology) birth cohort collected information on participants' tobacco smoke exposure through repeated questionnaires, and measured saliva cotinine concentrations at age 16 years. Participants performed spirometry and impulse oscillometry (IOS) at age 16 years (n=2295).Exposure to maternal smoking during pregnancy was associated with reduced forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) ratio of −1.1% (95% CI −2.0 to −0.2%). IOS demonstrated greater resistance at 5–20 Hz (R5–20) in participants exposed to maternal smoking during pregnancy. Adolescents who smoked had reduced FEV1/FVC ratios of −0.9% (95% CI −1.8 to −0.1%) and increased resistance of 6.5 Pa·L–1·s (95% CI 0.7 to 12.2 Pa·L–1·s) in R5–20. Comparable associations for FEV1/FVC ratio were observed for cotinine concentrations, using ≥12 ng·mL−1 as a cut-off for adolescent smoking.Maternal smoking during pregnancy was associated with lower FEV1/FVC ratios and increased airway resistance. In addition, adolescent smoking appears to be associated with reduced FEV1/FVC ratios and increased peripheral airway resistance.