Parental smoking and lung function in children: an international study.
BACKGROUND
Both prenatal and postnatal passive smoking have been linked with respiratory symptoms and asthma in childhood. Their differential contributions to lung function growth in the general children's population are less clear.


OBJECTIVE
To study the relative impact of pre- and postnatal exposure on respiratory functions of primary school children in a wide range of geographic settings, we analyzed flow and volume data of more than 20,000 children (aged 6-12 yr) from nine countries in Europe and North America.


METHODS
Exposure information had been obtained by comparable questionnaires, and spirometry followed a protocol of the American Thoracic Society/European Respiratory Society. Linear and logistic regressions were used, controlling for individual risk factors and study area. Heterogeneity between study-specific results and mean effects were estimated using meta-analytic tools.


RESULTS
Smoking during pregnancy was associated with decreases in lung function parameters between -1% (FEV1) and -6% maximal expiratory flow at 25% of vital capacity left (MEF25). A 4% lower maximal midexpiratory flow (MMEF) corresponded to a 40% increase in the risk of poor lung function (MMEF < 75% of expected). Associations with current passive smoking were weaker though still measurable, with effects ranging from -0.5% (FEV1) to -2% maximal expiratory flow (MEF50).


CONCLUSIONS
Considering the high number of children exposed to maternal smoking in utero and the even higher number exposed to passive smoking after birth, this risk factor for reduced lung function growth remains a serious pediatric and public health issue.
Institute Environmental Health, ZPH, Medical University, Vienna, Austria.
Hanns
H
Moshammer
Gerard
G
Hoek
Heike
H
Luttmann-Gibson
Manfred A
MA
Neuberger
Temenuga
T
Antova
Ulrike
U
Gehring
Frantiska
F
Hruba
Sam
S
Pattenden
Peter
P
Rudnai
Hana
H
Slachtova
Renata
R
Zlotkowska
Tony
T
Fletcher
D002648:Child; D005060:Europe; D005260:Female; D006801:Humans; D007223:Infant; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D009656:North America; D010290:Parents; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D012123:Pulmonary Ventilation; D012140:Respiratory Tract Diseases / Q000209:etiology* / Q000503:physiopathology; D011795:Surveys and Questionnaires; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*; D014797:Vital Capacity
D014028:Tobacco Smoke Pollution