NEW YORK (Reuters Health) - Secondhand exposure tocigarette smoke is an asthma trigger in children and a new studyshows that smoking by the primary caregiver and daycare providerare important sources of smoke exposure in children withasthma.

In the study, children with asthma who were exposed tosecondhand smoke “had as much smoke exposure as if their mothersmoked,” Dr. Harold J. Farber told Reuters Health.

Children with a double hit of smoke exposure - from both theirdaycare provider and primary caregiver - had the highest levels ofnicotine metabolites in their urine, said Farber, of TexasChildren’s Hospital in Houston.