asthma, antibiotic, smoking, infant
An Assorted Diet in Infancy Can Lower Allergy Risk
There is no clear evidence that allergen avoidance or delayed introduction of foods has any beneficial effect. A recent study was conducted to assess relationship between food diversity and other allergic diseases. The study included 856 children and included information on feeding during the first year of life from parental diaries. Follow-up questionnaires were used to collect data on the development of asthma, allergic rhinitis, food allergies and atopy up to 6 years of age. Based on a score consisting of six food items, children with a more diverse diet during the first year of life were at lower risk of allergic diseases. This score was inversely associated with asthma risk and food allergy.
There was an increased expression of forkhead box protein 3, a transcription factor for regulatory T cells which led to a decreased expression of IgE. There is a protective effect from a Th1/Th2 balance shift from the induction of regulatory T cells.
A Grandmother’s Smoking Can Affect Grandchildren’s Asthma Risk
Childhood asthma risk is affected not only by mother’s smoking, but by in utero exposure to grandmother’s smoking. A recent longitudinal study was performed to evaluate effects of grandmother’s smoking on childhood asthma risk. IT looked at 966 cases of asthma and 5,915 controls without asthma.
Prenatal exposure of the mother to cigarette smoke did not affect the grandchildren’s risk of being diagnosed with asthma. However, paternal prenatal exposure to their own mother’s smoking was associated with increased risk of persistent wheezing in the daughters of those fathers.
While these results are interesting, the author caution that the results are based on reported symptoms without corroborating biologic evidence.
Does Early Antibiotic Use Increase Asthma Risk?
The use of antibiotics during infancy might contribute to the rising prevalence of childhood asthma. These effects may arise on the composition of the intestinal microbiota. 62,576 US children enrolled from birth through age 5 from 1999 through 2006 were reviewed for antibiotic exposure during the first year of life and the development of three asthma phenotypes. These included transient wheezing, late-onset asthma (starting after 3 years), and persistent asthma (starting by 3 years and continuing 4- 7 years).
Children exposed to antibiotics were more likely to develop transient wheezing, odds ratio (OR) 2.0, and persistent asthma OR 1.6. There was a significant dose-response effect in children receiving at least 5 courses of antibiotics, OR ratio of 2. This analysis suggests that antibiotic exposure during the first year of life is associated with increased risk of asthma during the first 3 years of life.
Almost 20% of children developed wheezing or asthma between infancy and 7 years. With each course of antibiotic exposure, there was an increased risk of developing asthma. There was also a significant association between early-life upper respiratory infections and each type of asthma phenotype. This study is another warning about the importance of judicious use of antibiotics in children.