Some childhood breathing problems may have been caused by exposure to cleaning and other household chemicals, according to new research.

British researchers found that young children whose mothers used more household chemicals during pregnancy were at greater risk of wheezing than other children.

The more often that mothers used bleach, disinfectants, glass cleaner and insect sprays, the greater their children's odds of developing a wheezing problem by age seven.

The more often that mothers used bleach, disinfectants, glass cleaner and insect sprays, the greater their children's odds of developing a wheezing problem by age seven.

The study, published in the European Respiratory Journal, did not attempt to prove a direct causal link between household chemicals and children's lung problems.

"We can only state that there is an association between frequent use of this range of products, and the message should probably be 'use in moderation,'" said lead researcher Dr. John Henderson of the University of Bristol. The study followed 7,162 UK children from birth. During pregnancy, their mothers were asked how often they used various household chemicals. After their children were born, mothers were periodically asked about any wheezing symptoms the child may have developed.

The children's risk of wheezing paralleled their mothers' use of household chemicals.

It is possible that breathing the products irritates young children's airways and causes inflammation, Henderson explained. It is less clear, however, which specific home products might be the to blame.

"Until the effects are better understood, we cannot recommend substituting any particular product with safer alternatives," Henderson said.