Maternal smoking in prenatal and early postnatal life and the risk of respiratory tract infections in infancy. The Generation R study.
OBJECTIVE
To assess the associations of maternal smoking during pregnancy and in the postnatal period with respiratory tract infections in young infants.


METHODS
This study was embedded in the Generation R Study, a population-based prospective cohort study from fetal life onwards. All data were assessed by questionnaires. Maternal smoking was assessed in pregnancy (no, stopped when pregnancy was known, continued during pregnancy) and at 6 months postnatally. Doctor-attended respiratory tract infections were recorded at the age of 6 months. The present analyses were based on 3,418 subjects.


RESULTS
Continued maternal smoking during pregnancy was not associated with respiratory tract infections in young infants. Maternal smoking in the postnatal period showed a tendency for an increased risk of lower respiratory tract infections in infants (adjusted odds ratio (aOR) 1.61 (95% confidence interval: 0.99, 2.63)). Dose-response effects for maternal smoking during pregnancy or in the postnatal period on the risk of respiratory tract infections were not observed. In infants of mothers who smoked neither during pregnancy nor in the postnatal period, environmental smoking during pregnancy and in the postnatal period together was associated with upper respiratory tract infections (aOR 1.58 (95% CI: 1.07, 2.35)).


CONCLUSIONS
No effect of maternal smoking during pregnancy with respiratory tract infections was observed. Weak evidence for the association between maternal smoking in the postnatal period and lower respiratory tract infections were found. Exposure to non-maternal environmental smoking during pregnancy and in the postnatal period together increases the risk of upper respiratory tract infections in young infants.
The Generation R Study Group, Erasmus Medical Center, Rotterdam, The Netherlands.
Liesbeth
L
Duijts
Vincent W V
VW
Jaddoe
Albert
A
Hofman
Eric A P
EA
Steegers
Johan P
JP
Mackenbach
Johan C
JC
de Jongste
Henriëtte A
HA
Moll
D000328:Adult; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007223:Infant; D008425:Maternal Behavior; D009035:Mothers; D009426:Netherlands / Q000453:epidemiology; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D011446:Prospective Studies; D012141:Respiratory Tract Infections / Q000453:epidemiology*; D012907:Smoking / Q000009:adverse effects*; D011795:Surveys and Questionnaires; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*
D014028:Tobacco Smoke Pollution