environmental tobacco smoke (ETS) during childhood and in utero
exposure to maternal smoking are associated with adverse effects on
lung growth and development.
METHODS—A study was
undertaken of the associations between maternal smoking during
pregnancy, exposure to ETS, and pulmonary function in 3357 school
children residing in 12 Southern California communities. Current and
past exposure to household ETS and exposure to maternal smoking in
utero were assessed by a self-administered questionnaire completed by
parents of 4th, 7th, and 10th grade students in 1993.Standard linear
regression techniques were used to estimate the effects of in utero and
ETS exposure on lung function, adjusting for age, sex, race, Hispanic
ethnicity, height, weight, asthma, personal smoking, and selected
exposure to maternal smoking was associated with reduced peak
expiratory flow rate (PEFR) (-3.0%, 95% CI -4.4 to -1.4), mean mid
expiratory flow (MMEF) (-4.6%, 95% CI -7.0 to -2.3), and forced
expiratory flow (FEF75) (-6.2%, 95% CI -9.1 to -3.1),
but not forced expiratory volume in one second (FEV1). Adjusting for household ETS exposure did not substantially change these
estimates. The reductions in flows associated with in utero exposure
did not significantly vary with sex, race, grade, income, parental
education, or personal smoking. Exposure to two or more current
household smokers was associated with reduced MMEF (-4.1%, 95% CI
-7.6 to -0.4) and FEF75 (-4.4%, 95% CI -9.0 to 0.4).
Current or past maternal smoking was associated with reductions in PEFR and MMEF; however, after adjustment for in utero exposure, deficits in
MMEF and FEF75 associated with all measurements of ETS were substantially reduced and were not statistically significant.
exposure to maternal smoking is independently associated with decreased
lung function in children of school age, especially for small airway flows.