Children exposed to the dust of the collapsed World Trade Center after the September 11 attacks on New York in 2001 are twice as likely to have asthma as other children, health officials said Wednesday.
The findings by the New York City health department reflect similar studies on asthma in adults caught up in the tragedy.
According to the survey, half of 3,100 children enrolled in the World Trade Center Health Registry had developed at least one new or worsened respiratory symptom between the attacks and their interviews in 2003 and 2004.
The registry was set up in 2003 to track the health of rescue workers, New York residents and office workers affected by the attacks.
"Children exposed to the dust cloud following the collapse of the towers were twice as likely to be diagnosed with asthma as those not caught in the dust cloud," the health department said in a statement.
"The survey found that children under five had an increased likelihood of being diagnosed with asthma in the two to three years following the event, though not as sharp an increase as rescue workers," it added.
However, the study showed that children from downtown Manhattan were no more likely to be suffering from post-traumatic stress than any other children.
Officials were conducting a follow up survey to assess whether children were still experiencing worsened respiratory symptoms six years after the attacks.
The department said further research was needed to assess whether some of the increase in asthma rates was due to better detection of asthma in children with exposure to the World Trade Center or because parents of children with asthma symptoms were more likely to enroll their children in the registry.
The survey included children under 18 at the time of the attacks who lived or went to school in downtown Manhattan in September 2001, or were visiting when the atrocity occurred.