Bad habits may help battle allergies
Thumb sucking, nail biting expose kids to microbes
Hamilton resident Stacey Allen-Cillis and her husband Calum Cillis have a couple of children; 11-year-old Oliver and 10-year-old Piper. They have taken a “hands-on” approach to raising them.
“They’ve been exposed to dirt, the garden, nature and just being outside since they were young children,” said Allen-Cillis.
Piper started sucking her thumb within the first few months of her life, while Oliver didn’t. “As soon as she found her thumb, it was in her mouth,” Allen-Cillis said.
Piper later swapped one habit for another — nail biting — another common behaviour some children adopt.
Both may be frowned upon but, according to a study published Monday in the Journal Pediatrics, children who suck their thumbs or bite their nails may be less likely to develop allergies.
The new study suggests those habits in children ages five to 11 may increase their exposure to microbes, which may not be a bad thing, and, if they have both habits, the chance of developing allergies reduces by another 30 per cent according to the results.
“It confirms what we’ve been saying; excessive hygiene may be one reason for increasing allergies,” said Dr. Malcolm Sears of McMaster University’s Michael G. DeGroote School of Medicine. “Don’t be afraid of a little dirt.”
Allen-Cillis was surprised to hear the results. “It’s interesting because our son, he has more environmental allergy reactions … He never sucked his thumb or bit his nails.”
Piper on the other hand doesn’t have any environmental sensitivities, she developed both habits.
It falls in line with the long-term study by Sears and researchers of New Zealand’s Dunedin School of Medicine. They followed more than 1,000 children born in 1972 and ’73 in Dunedin, a coastal city in New Zealand. They were checked and tested “every two years” as they grew up. The most recent testing was done at age 38, another test will be done at age 45.
“Thirteen was the first time we were able to skin test,” said Sears, who joined the study when the children were age seven, then was recruited by McMaster University’s department of medicine in 1990. The same children were tested again at age 32.
Researchers described 31 per cent of the children in the study group as “frequent thumb suckers or nail biters.” Of those who sucked their thumbs or bit their nails “only 40 per cent had allergies.” Of those with both habits, “only 31 per cent had allergies.”
They tested about a dozen or more common allergens; cats, dogs, horse, house dust mites and grasses were listed in a news release.
“We didn’t find any change in asthma or hay fever as the children grew up,” Sears said. “We’re learning more and more about how much our body is made up of microbes. We have more genes from our bacteria then from our human cells.
“While we’re not encouraging the habits, those who did it were exposed to bacteria, it gave them an immune advantage so they are less likely to develop allergic sensitization,” said Sears, also a researcher for the Firestone Institute for Respiratory Health at McMaster and St. Joseph’s Healthcare Hamilton.
It’s welcome news for Allen-Cillis who frequently sees Piper biting her nails and reminds her to be aware of it. “She has better habits with hand washing now at this age so I’ve stopped being so adamant about the nail biting.”
Excessive hygiene may be one reason for increasing allergies. DR. MALCOLM SEARS