METHODS

Design:

randomised controlled trial.

Allocation:

{concealed*}†.

Blinding:

blinded (clinical outcome assessors).*

Follow up period:

1 year of intervention followed by a 1 year observational period.

Setting:

7 major cities in the US.

Patients:

937 children 5–11 years of age (mean age 7.7 y, 63% boys) with atopic asthma who were residents of census tracts in which ⩾20% of the households had incomes below the federal poverty level. Children were also required to have had ⩾1 asthma related hospital admission or 2 unscheduled, asthma related visits to the clinic or emergency department during the previous 6 months and a positive skin test in response to ⩾1 of 11 indoor allergens.

Intervention:

a 1 year …