Pregnancy During Spring May Boost Kid's Risk of Food
WEDNESDAY, Oct. 20 (HealthDay News) -- The chances of a child
developing food allergies may be increased if that child is
conceived in the early spring, a preliminary study by Finnish
Studies have already shown that children born in autumn or
winter are more likely to eczema, wheeze and asthma than children
born in spring or summer, the researchers noted.
There may be several reasons for this new finding, said lead
researcher Dr. Kaisa Pyrhonen, of the Institute of Health Sciences
at the University of Oulu, including concentration of pollen in
spring, exposure to sunlight, which is related to synthesis of
vitamin D, and viral infections.
"These are possible explanations, but our study design did not allow any assessment of the causal role of the above factors," Pyrhonen said.
Pyrhonen said the study findings are preliminary and families
should not plan pregnancies around specific times. "Because our
study was an observational study, we cannot give any
recommendations to families," Pyrhonen said.
The report is published in the Oct. 20 online edition of the
Journal of Epidemiology and Community Health.
For the study, Pyrhonen's team collected data on 5,920 Finnish
children born between 2001 and 2006. From birth to four years, 961
of these children were tested for food allergies.
Up to age of 4, the odds of having a food allergy varied
according to season of birth, ranging from 5 percent for children
born in June and July to 9.5 percent for those born in October and
November, the researchers found.
In fact, 11 percent of children whose 11th week of development
occurred during April or May had food allergies, compared with 6
percent of children who reached that stage of development in
December or January, Pyrhonen's group found.
In terms of specific allergies, a child whose first three months
of fetal development ended in April or May was three times more
likely to be allergic to milk and eggs compared with those who
reached that stage in November or December, the researchers
Commenting on the study, Dr. Erick Forno, an assistant professor
of pediatrics at the University of Miami Miller School of Medicine,
said there could be a variety of reasons for this finding.
"But what is important is that we are understanding more that there are environmental factors that at some point during pregnancy play an important role in developing the immune system that predisposes the kid to have either food allergies or environmental allergies or asthma or eczema or something of that sort," he said.
Forno cautioned that this was an observational study (a type of
study in which people are observed or certain outcomes are measured
and no effort is made to affect the outcome -- for instance, no
treatment is given). "So there may be other things that these
researchers didn't measure that are also associated. What they are
looking at is the common consequence. So we can't say it's a causal
association," he said.
Parents need to realize that things outside the uterus are very
important in the developing fetus, Forno said, adding, "We are only
beginning to understand what goes on."
For more information on allergies, visit the
U.S. National Library of Medicine.
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