Senior researcher Dr. Robert Hancox of the University of Otago in Dunedin, New Zealand, maintains that encouraging these habits is not appropriate, and that there is concern regarding thumb sucking and the way a child’s teeth grow in. For children who find it hard to break this habit Hancox suggests, “maybe there is some consolation in the fact that there may be a reduction in the risk of allergies.”
Many people wonder how exposing oneself to germs through thumb sucking and nail biting would prevent allergies and actually strengthen the immune response.
According to Hancox, it all relates to the “hygiene hypothesis.” This theory suggests that exposure to bacteria and other microbes in early life actually helps to steer the immune system toward infection-fighting mode, strengthening the body’s defense system against allergies, which is itself a highly sensitive immune response.
Although the study cannot prove that either habit does reduce a child’s risk to allergy sensitization, it did account for factors that increase sensitization, such as whether the child was breastfed, exposure to second-hand smoke, living with pets, and a family history of allergies.
Dr. Mika Hiramatsu, a pediatrician and spokesperson for the American Academy of Pediatrics who reviewed the study, observed connections in previous studies that back up the hygiene hypothesis.
Kids going to daycare, living with pets, living on farms, or having older siblings tend to have a lower risk of allergies and asthma. This suggests that germ-filled environments may offer some protection. “I think this study adds weight to the idea that kids do better when they’re exposed to a variety of microbes,” Hiramatsu said. “Being in a ‘sterile’ environment is not actually the best thing for us.”
Don’t encourage your children to “roll around in the dirt”, of course, but recognize that you can slightly relax about keeping their surroundings exceptionally clean.
The findings are based on data from 1000 New Zealand children who entered the study at birth and were followed into adulthood. According to parents’ reports, 31 percent of children were either sucking their thumb or biting their nails “frequently” between ages five to 11. Those children were then one-third less likely to develop allergies, compared to their peers. They also were less likely to test positive when exposed to allergy triggers like pollen and dust mites via skin testing.
Also, read Bel Marra Health’s article: Tips to protect your child from allergies and the sun this summer.
Sources:
http://pediatrics.aappublications.org/content/early/2016/07/07/peds.2016-0443