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Studies of children's asthma risk increased by air pollution during pregnancy
Every expectant mother tries to avoid all risks that could affect the child's health. Some illnesses, however, already occur in the womb, because the mothers, for example, live unhealthily or have made other mistakes. For example, children's asthma risk may be related to the air pollution the mother was exposed to during her pregnancy.
If expectant mothers are permanently exposed to negative environmental influences, this may affect their unborn children. For example, young children have an increased likelihood of developing asthma, when the mother has lived near a highway in pregnancy, Canadian researchers from the University of British Columbia report from their recent study results. The scientists have published these in the journal "European Respiratory Journal".
High levels of fine congestion during pregnancy lead to a rising risk of asthma in the offspring. (Image: fotohansel / fotolia.com) Childhood asthma risk increased by 25 percent if the mother lives next to a highway
In their study, Canadian researchers investigated the effects of environmental influences on expectant mothers. In one of the largest birth cohort studies, physicians found that children are 25 percent more likely to develop asthma if their mothers lived close to a highway during pregnancy. Vehicle emissions contain many pollutants, such as nitrogen dioxide and carbon monoxide, explain the researchers. These increase the burden of their asthma risk. Children with a low birth weight generally have an increased risk of asthma compared to children with normal birth weight, explains Hind Sbihi of the University of British Columbia.
Canadian study looks at 65,000 children for asthma risk
The study involved more than 65,000 children born between 1999 and 2002 in Vancouver. Physicians watched these children from birth to the age of 10 years. Subjects were randomized into five different test groups. The researchers wanted to find a link between the effects of environmental influences in the womb and later asthma diseases, the experts say. The assessment of maternal exposure to air pollution during pregnancy was made with the help of land use and regression models. This linked traffic-related air pollution with the mother's home address, explain the researchers. Measurements of air pollutants from monitoring stations near the mother's place of residence were also included in the analysis. In addition, it was noted whether the mothers lived near a major road or highways, the doctors add.
Low birth weight favors the development of asthma
Children who developed early asthma were mostly born of younger mothers, had shorter gestation periods and low birth weight. Many of the children also live in poverty and were probably less breastfed, the researchers say. It was clear that environmental toxins such as nitric oxide, nitrogen dioxide and carbon monoxide increase the risk for children of developing asthma during their first years of life. Sulfur dioxide and fine dust also seem to favor asthma, explain the experts. When babies weighed less than 2,500 grams at birth, they had an increased risk of air pollution developing asthma, the researchers said.
The Canadian researchers report that several other birth cohort studies examining the role of air pollution in asthma prevalence in early life show mixed results. For example, a UK study found no link between nitrogen dioxide and asthma in children up to the age of 11 years. A Swedish birth cohort study, however, found clear effects of air pollution that favor asthma. However, the Swedish scientists were only able to observe these results in older children. However, a Dutch study published in 2010 showed that there is a link between nitrogen dioxide and asthma at the age of two to four years, explain the researchers. A restriction in the current study is the lack of data on environmental influences that had nothing to do with the place of residence, explain the doctors. (As)