Vinyl flooring linked to asthma in children
Huan Shu, Bo A. Jönsson, Malin Larsson, Eewa Nånberg, and Carl-Gustaf Bornehag. 2013. PVC-flooring at home and development of asthma among young children in Sweden, a 10-year follow-up. International Journal of Indoor Environment and Health. http://dx.doi.org/10.1111/ina.12074
Children who lived in homes with vinyl floors were more likely to develop asthma than children who lived in homes with other types of flooring, according to a new study conducted in Sweden. The association was strongest for children whose parents had vinyl flooring in their bedrooms during pregnancy.
The scientists who conducted the research say that the association could be the result of phthalates, which are chemicals used to soften vinyl. Previous studies have reported links between phthalate exposure and breathing problems, including asthma and wheezing.
The scientists examined the health of more than 3,000 children whose parents responded to questionnaires at the beginning of the study, and then during follow-ups five and 10 years later.
The 10-year follow-up showed that children with vinyl (PVC) flooring in their bedroom were 1.5 times more likely to have doctor-diagnosed asthma than children who had wood, linoleum or other flooring materials in their bedrooms. If their mothers had vinyl flooring in their bedrooms while pregnant, children were twice as likely to develop asthma compared to other flooring types. The association was stronger for children who lived at the same location since birth.
Children who had vinyl flooring in their parents' bedroom but not their own had a stronger association than children who had vinyl flooring in their own room but not their parents' room. This suggests that prenatal exposures may be important.
"Our results suggest PVC flooring exposure during pregnancy could be a critical period in the development of asthma in children at a later time," the authors wrote.
The statistical analysis controlled for several variables that might confuse the findings, including whether family members had allergies or smoked.
The scientists acknowledged several limitations of the study, most notably that it was based on questionnaires and could be subject to memory errors. On the other hand, the assessment of flooring materials took place at the beginning of the study so it should not have been vulnerable to recall bias.
Another limitation is that dust in the bedrooms was not analyzed for phthalates. However, previous research has shown that dust in bedrooms with vinyl floors is more likely to have two types of phthalates, DEHP and BBzP. Because these phthalates are not bound chemically to the PVC, they can leach out and be absorbed by dust, which creates a pathway for human exposure.