How Environmental Factors Impact Infantile Eczema

This research was part of an ongoing prospective cohort study investigating the impact of prenatal exposure to outdoor and indoor air pollution on infants, conducted in New York and Krakow. It is already known that infantile eczema is influenced by the age of the mother, mother’s smoking habit and atopic disease history. Some reports have suggested that breastfeeding and maternal fish intake reduce the risk for infantile eczema. The findings of this study indicated that high prenatal exposure to air pollutants and postnatal exposure to environmental tobacco smoke (ETS) increased the risk of infant eczema. The risk was reduced by maternal fish intake during pregnancy.

Eczema, which generally occurs in the first year of life, is considered as the body’s immunologic reaction to allergens. The infant’s genetic makeup also influences eczema occurrence. The rise in the prevalence of infantile eczema over the last ten years suggests a higher role played by environmental factors in the prenatal and perinatal periods of a genetically predisposed baby. Previous studies have focused on factors affecting eczema in the postnatal period with inadequate data on preventive factors in the prenatal period. This study aims to assess the effects of environmental factors and maternal fish intake during pregnancy on eczema occurrence.

* The study included 469 non-smoking pregnant women aged 18 to 35 years, who delivered full-term singleton babies. Data on house characteristics, occupational hazards, dietary habits, smoking and alcohol consumption of other members in the house was collected by a questionnaire.
* Exposure to fine particulate matter was measured in each woman, with a personal environmental monitoring sampler, over 48 hours in the second trimester of pregnancy. The sampler was a lightweight device worn in a backpack during the daytime by the woman and placed near the bed at night. Food frequency questionnaires were used to collect information on fish consumption, classified as: never, less than once per month, once weekly, one to two times weekly; three to four times weekly or daily (each fish meal was considered as 150 g).
* After delivery, once every three months, data on infantile eczema symptoms and probable environmental risks was collected from the mother by interview.
* Statistical models of regression analyses were used to estimate the risk of developing eczema in relation to the two variables: antenatal exposure to air pollutants and environmental tobacco smoke and fish intake by mothers.

Data/Results/Key findings
* The fine particulate matter concentration levels measured in pregnant mothers were higher in homes with other members smoking a higher number of cigarettes daily.
* The prevalence of eczema was 54.6 percent in infants exposed to postnatal environmental tobacco smoke and higher antenatal levels of fine particulate matter. The risk of eczema occurrence decreased by 43 percent when the pregnant women consumed more than 205 g/week of fish while eczema stayed at 30.4 percent.
* Incidence rate ratio (IRR) for eczema symptoms was higher in infants with high antenatal exposure to air pollutants and postnatal environmental tobacco smoke exposure.
* There was an increase in the frequency of eczema symptoms in children of mothers who reported low fish intake (IRR of 1.00) compared to those whose mothers reported high fish intake (IRR of 0.72).

Next steps/shortcomings
In this study, basing the eczema diagnosis on the mothers’ interview could have introduced a possible maternal reporting bias. The method of data collection on fish consumption was not completely reliable. The fish intake portions were not weighed, but an approximate measure was assumed. There was no information on the type of fish consumed.

The results of this study showed a doubling of the risk of eczema occurrence with high antenatal exposure to air pollutants and postnatal ETS exposure. Higher fish consumption in pregnancy was found to decrease the risk of infantile eczema occurrence. Fine particulate matter comprises toxins such as sulfates, metals, wood smoke, tobacco smoke, and polycyclic aromatic hydrocarbons, which could adversely affect fetal development. Transplacental exposure to these toxins from maternal inhalation could induce immune response; thus increasing the occurrence of eczema symptoms. Postnatal exposure to air pollutants may increase the damage caused by the prenatal exposure. The results of this study hold an important key for preventive therapy for eczema in children.

For More Information:
Effects of Prenatal and Perinatal Exposure to Fine Air Pollutants and Maternal Fish Consumption on the Occurrence of Infantile Eczema
Publication Journal: International Archives of Allergy and Immunology, February 2011
By Wieslaw Jedrychowski; Frederica Perera; Jagiellonian University Medical College, Krakow, Poland, and Columbia University, New York, New York

*FYI Living Lab Reports Are Summaries of the Original Research.

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