Thumb-sucking, nail-biting kids develop fewer allergies–study

Children who are nail biters and thumb suckers are less likely to grow allergic sensitivities upon reaching adulthood, according to a new study conducted in New Zealand.

The study, published in the journal Pediatrics, showed that kids ages 5 to 11 who repeatedly performed the “nasty” habits developed fewer allergies to house dust mites, grass, cats, dogs or airborne fungi. Hence, the findings resonate well with the “hygiene hypothesis,” which infers that childhood exposure to microbial organisms modifies the child’s immune functions.

Malcolm Sears, the study’s co-author, said in a statement, “Our findings are consistent with the hygiene theory that early exposure to dirt or germs reduces the risk of developing allergies.”

As a result, these nail-biting and thumb-sucking kids have fewer chances to develop atopy, a hyperallergic condition resulting in skin asthma or eczema. Also, these bad habits introduce kids to a wide range of germs and microorganisms.

The researches from New Zealand’s Dunedin School of Medicine an Researchers who did the ground-breaking study, extracted data from Dunedin Multidisciplinary Study, which cited the results of 1,037 participants born in Dunedin, New Zealand, from 1972 to 1973. They first interrogated the participants’ parents on their kids’ frequent thumb-sucking and nail-biting habits at ages 5, 7, 9 and 11. Then, participants’ atopic sensitization was measured by skin-prick testing at 13 and then at 32 years of age.

At the first testing, 45 percent of 13-year-olds tested positive for atopy, although only 40 percent of those who either bit their nails or sucked their thumbs were found to have the condition. Study participants with both of these habits had only 31 percent.

Children who picked up both of the bad habits were less likely to develop allergies at age 13 while those who either are nail-biters or thumb-suckers experience fewer allergies at 32.

Other deviants and factors were keenly considered in the study, such as parents with allergies, breastfed children and pets at home.

However, the study did not find any correlation between the “bad habits” and the rate of developing asthma or hay fever. Gianna Francesca Catolico