Biting Fingernails linked to lead poisoning in polluted regions
Russian children in contaminated towns show psychological development delays as result
EKATERINBURG, RUSSIA-Not only is fingernail biting a bad habit, but it may also contribute to lead poisoning, said research physicians here at the Ural Regional Centre for Environmental Epidemiology.
“If a child is in the habit of biting nails, lead poisoning can become the reason for his or her psychological development delay,” said the centre’s deputy director, Dr. Larissa Privalova.
In five towns they suspected high environmental lead concentrations, Dr. Privalova and her team measured lead content in the blood of pre-school age children, many of whom were chronic nail biters.
“The worst situation was in the town on Krasnouralsk where the big brass works are located, in the vicinity of blocks of flats,” she explained. “In this town, the blood concentration of lead exceeded the ‘level of concern’ of 0.1 mg/L in more than 60% of children.”
Children who “ate soil, snow, paint, or bit their nails,” not only showed higher blood-lead concentration, but also performed less proficiently on a battery of psychological tests the researchers administered. Among their subjects, “more than 69% of girls and about 62% of boys were in the habit of biting nails,” Dr. Privalova said.
Lead from fingernail biting almost certainly comes from soil and dust lodged under the nails, explained Long Island, N.Y.-based dermatologist Dr. Joshua Fox.
“There is no lead in nail hardeners, nail polishes, or other nail applied cosmetics,” Dr. Fox said. “I have never tested a nail biter for lead poisoning, but the connection makes perfect sense.”
Calling the research a “public service,” Dr. Fox said the link between lead poisoning and nail biting may never have been discovered in a less-contaminated environment.
“I have no doubt the research results were skewed because of the high concentration of lead in that heavily industrialized region,” Fox told the Medical Post. “Since fully one-third of all children bite their nails, however, this research is clearly important.”