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[00:01.00]New research suggests that very young babies who are with other children are less likely to suffer later from the breathing disease asthma.
[00:14.03]Asthma is a disease in which small air passages in the lungs become temporarily blocked.
[00:23.78]This causes difficulty breathing.
[00:28.03]The disease affects an estimated seventeen-million Americans.
[00:34.82]Every year,more than five-thousand people die of asthma in the United States.
[00:42.66]It is the most common disease among children.
[00:47.10]Day care centers are places where babies and children are cared for while parents are at work.
[00:57.03]Researchers studied babies of different ages in day care centers.
[01:04.03]They found that babies up to six months old gained the most protection from asthma.
[01:12.83]They were only about half as likely to have asthma age thirteen as babies who did not attend day care until later.
[01:23.62]Babies who entered day care after the age of six months also received some protection from asthma.
[01:34.41]But they did not get as much protection as the younger babies.
[01:41.02]Children who entered day care after the age of one showed no increased protection against the disease.
[01:50.95]The study also found that children with two or more older brothers or sisters at home also had a lower risk for asthma.
[02:03.35]Scientists believe early experiences with bacteria and viruses may help develop a baby's defense system against disease.
[02:16.31]Scientists at the University of Arizona College of Medicine did the study.
[02:23.31]They studied more than one-thousand children for more than thirteen years.
[02:31.15]They also studied the substances in the children's environment that caused breathing problems.
[02:39.95]American health officials say asthma cases have increased more than one-hundred percent since Nineteen-Eighty.
[02:51.11]Experts say families with fewer children could result in the weakening of a child's defense against disease.
[03:02.26]Scientists also say homes cleaned with products that fight bacteria could create the same problem.
[03:12.40]The asthma study provides evidence for the idea that keeping a baby in an environment almost free of germs may cause problems later in life.
[03:25.64]The study was organized by the National Heart,Lung and Blood Institute.
[03:32.46]The results were published recently in the New England Journal of Medicine.
