Prenatal and postnatal tobacco smoke exposure and respiratory health in Russian children.
BACKGROUND
Only few studies have assessed the relative impact of prenatal and postnatal exposure to tobacco smoke on the child's later asthma or chronic respiratory symptoms and to our knowledge no studies have elaborated respiratory infections and allergies in this context.


OBJECTIVE
To assess the effects of prenatal and postnatal exposure to tobacco smoke on respiratory health of Russian school children.


METHODS
We studied a population of 5951 children (8 to 12 years old) from 9 Russian cities, whose parents answered a questionnaire on their children's respiratory health, home environment, and housing characteristics. The main health outcomes were asthma, allergies, chronic respiratory symptoms, chronic bronchitis, and upper respiratory infections. We used adjusted odds ratios (ORs) from logistic regression analyses as measures of effect.


RESULTS
Prenatal exposure due to maternal smoking had the strongest effects on asthma (adjusted OR 2.46, 95% CI 1.19-5.08), chronic bronchitis (adjusted OR 1.45, 95% CI 1.08-1.96) and respiratory symptoms, such as wheezing (adjusted OR 1.30, 95% CI 0.90-1.89). The associations were weaker for exposure during early-life (adjusted ORs 1.38/1.27/1.15 respectively) and after 2 years of age (adjusted ORs 1.45/1.34/1.18) compared to prenatal exposure and the weakest or non-existent for current exposure (adjusted ORs 1.05/1.09/1.06). Upper respiratory infections were associated more strongly with early-life exposure (adjusted OR 1.25, 95% CI 1.09-1.42) than with prenatal (adjusted OR 0.74, 95% CI 0.54-1.01) or current exposure (adjusted OR1.05, 95% CI 0.92-1.20). The risk of allergies was also related to early life exposure to tobacco smoke (adjusted OR 1.26, 95% CI 1.13-1.42).


CONCLUSIONS
Adverse effects of tobacco smoke on asthma, chronic bronchitis, and chronic respiratory symptoms are strongest when smoking takes place during pregnancy. The relations are weaker for exposure during early-life and after 2 years of age and weakest or non-existent for current exposure.
Institute of Occupational and Environmental Medicine, University of Birmingham, Birmingham, UK. j.jaakkola@bham.ac.uk
Jouni J K
JJ
Jaakkola
Anna A
AA
Kosheleva
Boris A
BA
Katsnelson
Sergey V
SV
Kuzmin
Larissa I
LI
Privalova
John D
JD
Spengler
D000367:Age Factors; D001249:Asthma / Q000453:epidemiology / Q000209:etiology*; D029481:Bronchitis, Chronic / Q000453:epidemiology / Q000209:etiology*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D018811:Maternal Exposure / Q000009:adverse effects; D011247:Pregnancy; D047928:Premature Birth; D011297:Prenatal Exposure Delayed Effects; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000209:etiology*; D012426:Russia / Q000453:epidemiology; D011795:Surveys and Questionnaires; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*
D014028:Tobacco Smoke Pollution