Background: Low birth weight and maternal smoking during pregnancy are associated with higher risk of asthma onset during childhood. Aims: To evaluate the effect of gender, race/ethnicity, birth weight, and maternal smoking during pregnancy on risk of first asthma onset at the ages of 1, 2, 3-6, 7-10, and 11-15 years.
Study design: Retrospective data from national health and nutrition examination survey (NHANES) for the years 1999-2012 were analyzed. Logistic regression models were fitted to estimate the odds of first asthma onset.
Subjects: Self-reported data on 20018 children aged ≤ 15 years collected by NHANES.
Outcome measures: Age at the onset of first asthma.
Results: Male children had higher odds of (OR>=1.27) first asthma onset than female children up to the age of 10 years. Compared to non-Hispanic white children, non- Hispanic black children had higher odds of (OR>=12.6) first asthma onset up to the age of 6 years and Mexican American children had lower odds (OR<=0.67) up to the age of six years. Low birth weight (<2500 grams) was associated with higher odds (OR>1.51) of first asthma onset when the age of onset was 1 year. Maternal smoking during pregnancy was also (OR=1.58) associated with higher odds (OR>1.51) of first asthma onset but only when the age of onset was 1 year.
Conclusion: While, low birth weight and maternal smoking during pregnancy are risk factors for first onset of asthma, their effect may be limited to first asthma onsets during first few years of life only.
Ram B Jain