Does anyone know the length of [exclusive] breastfeeding they're basing this
conclusion on?


http://www.medscape.com/viewarticle/456026
Study Finds No Asthma Protection From Breast-Feeding or Pets

Peggy Peck

May 21, 2003 (Seattle) — The latest results from the Children's Health
Study, a case-control study that has been following 3,000 Los Angeles
children since 1993, suggest that neither breast-feeding nor pets can reduce
the risk for asthma, but exposure to cockroaches and herbicides can
significantly increase risk.

Frank D. Gilliland, MD, PhD, professor of preventive medicine at the Keck
School of Medicine, University of Southern California, presented the results
here today at the American Thoracic Society 99th International Conference.

The Children's Health Study tracks respiratory health in all enrollees. The
researchers identified 338 children with physician-diagnosed asthma who were
diagnosed before age 5 years and matched them with 570 children who were
asthma-free. In addition to matching for age and community of residence, the
children were also matched for exposure to maternal smoking during
gestation.

Dr. Gilliland told Medscape that several findings in the current analysis
were surprising. "We expected that breast-feeding would be protective, but
it was not, and we expected that daycare would be protective, but exposure
to daycare before four months of age actually increased risk by a factor of
2.34," he said. But the most surprising finding was "that maternal age
greater than 35 was associated with a 70% increase in risk for asthma."

He said that while early daycare was associated with increased risk "having
siblings was associated with a reduced risk."

Among the other identified associations were:


Exposure to farm crops before age 1 increased risk nearly two times.
Exposure to wood or oil smoke or exhaust anytime from birth to age 5 years
increased risk more than 50%.
Exposure to herbicides increased risk by 4.5 times, and exposure to
pesticides increased risk by 2.4 times.

"We saw no effect of pets," said Dr. Gilliland.

One disturbing finding, he said, was that "about 90% of women who smoke
continue to smoke during pregnancy, even though smoking during pregnancy is
associated with a two-fold increase in risk of asthma."

Homer A. Boushey, Jr., MD, professor of medicine, chief of the division of
allergy/immunology and director of the Asthma Clinical Research Center at
the University of California, San Francisco, told Medscape that he has
reservations about several of the associations — or lack of associations —
reported by Dr. Gilliland.

"Cockroaches, wood or oil smoke, older siblings, that makes sense and these
findings are in concordance with associations reported in other studies,"
said Dr. Boushey. But he pointed out that several studies found that "pets
and farm animals are protective. "In one European study there was an
association with the level of endotoxins — and now we are really talking
about manure — found in bedding. Higher levels were protective." Dr.
Boushey, who was not involved in the study, is president-elect of ATS.

ATS 99th International Conference Mini-Symposium: Abstract Page A831. Risk
Factors for the Development of Asthma in Childhood (Hygiene Hypothesis) —
Early Life Risk Factors for Asthma: Findings from the Children's Health
Study. Presented May 21, 2003.

Reviewed by Gary D. Vogin, MD

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