Children from well-off families are more likely to suffer from a peanut allergy than their less-wealthy peers, according to British researchers.
The Telegraph’s Rebecca Smith reports that the link appears connected to the hygiene hypothesis – that cleaner homes tend to increase the risk of childhood allergies.
“The theory suggests that a lack of early childhood exposure to germs increases the chance for allergic diseases, that oversanitization might suppress the natural development of the immune system,” she writes.
Allergy to peanuts – like others such as to milk or shellfish – can cause a range of effects, from rashes and irritations to life-threatening anaphylactic shock.
Smith writes that study author Dr. Sandy Yip explained that the link appears to only affect people who develop an allergy in childhood, hence the link to the home environment.
“Overall household income is only associated with peanut sensitization in children aged 1 to 9 years,” Yip said of the findings, which were presented at an allergy conference hosted by the American College of Allergy, Asthma, and Immunology. “This may indicate that development of peanut sensitization at a young age is related to affluence, but those developed later in life are not.”
In the study of 8,306 patients, 776 had an “elevated antibody level to peanuts.” Men and racial minorities of all ages were more likely to have a peanut allergy. They also found that peanut allergies appear to peak when a person is 10 to 19, but tapers off after middle age, Smith reports.
While the study appears to bolster the hygiene hypothesis, it also seems to be based on the assumption that lower-income homes are less hygienic. Others in the field suggest that there’s good evidence that a child’s early diet also plays a major role.
Studies are finding that there is a protective effect if children are fed foods such as peanuts early in life. In one 2008 study, researchers compared Jewish children in the Britain, who ate no peanuts in the first 14 months of life with their peers in Israel, who ate a median of about 7 grams a month. The British kids had a 10-fold higher prevalence of peanut allergy, they found – after accounting for differences in allergy risk, social class, genetics and other factors.
As a result of this kind of work, public health bodies are suggesting that parents stop the long-held practice of delaying the introduction of allergens such as peanuts during the child’s first year of life (except when they’re a choking hazard, of course).
No word yet on whether anyone will prescribe keeping a less-tidy home.