Softening agents in their home linked to asthma and allergies

There is a clear co-variation between allergic symptoms in children and the concentration of softening agents in their homes. This is a finding made by a Swedish-Danish research team in a recently published study financed by Formas, the Swedish Research Council for Environment, Agricultural Sciences, and Spatial Planning.

“A great number of consumer products and surface materials like PVC mats contain softening agents, such as phthalate esters,” says Professor Carl-Gustaf Bornehag at Karlstad University and the Swedish National Testing and Research Institute, SP. World production of such softening agents has increased dramatically since the 1950s. At the same time, asthma and allergies have proliferated over the last 3-4 decades.

The study was carried out within the framework of the Dampness in Buildings and Health Study, DBH. In 2000 a questionnaire was sent out to cover all children in the province of Värmland (14,077 individuals). Answers were received from 79 percent regarding background factors, health, and housing factors. From these, 198 children with allergies and 202 healthy children were selected for in-depth study. Building inspectors checked the children’s homes, and dust and air samples were taken to determine their chemical and microbiological content. Dust from surfaces above the floor level in the child’s bedroom was gathered to determine the presence of softening agents. At the same time, the children underwent medical examinations and clinical samples were taken, including sensitivization (IgE antibodies in the blood).

“We found higher concentrations of butyl benzyl phthalate (BBzP) in the affected children compared with the healthy ones. Further it was shown that the concentration of BBzP co-varied with rhinitis (runny nose and eyes) and eczema, whereas di(2-ethylhexyl) phthalate (DEHP) co-varied with respiratory complaints such as asthma. Moreover, a dose-response association was found, that is, the higher the concentration of softening agent, the greater the reaction in the children,” says Jan Sundell, Professor at the Technical University of Denmark.

Four other phthalates were investigated but were not found to be associated with asthma and allergic reaction: diethyl phthalate (DEP), di-isobytyl phthalate (DIBP), di-n-butyl phthalate (DnBP), and di-isononyl phthalate (DINP).

“The study thus shows that normal concentrations of phthalate esters in indoor dust co-vary with allergies in children. We believe that the different associations for the three most prevalent phthalates, BBzP, DEHP, and DnBP can be explained by differences in chemical and toxicological properties.”