Canada’s first nationwide food allergy survey shows that about 1.7 per cent of children under 18 have a probable peanut allergy, while another 1.59 per cent have a probable allergy to tree nuts, such as hazelnuts and walnuts. “These are significant numbers,” says Dr. Moshe Ben-Shoshan, of McGill University in Montreal. “It’s a concern for a lot of people.” He says the rates are higher in Canada than in the U.S. — a 2002 American study found that 0.83 per cent of children have peanut allergies and 0.51 per cent are allergic to tree nuts. But Ben-Shoshan — who worked on the study led by Dr. Ann Clarke, an allergist at McGill’s health centre — says more current, but incomplete, American research indicates the U.S. may be catching up. “North America has a prevalence for the peanut allergy, while Asia has a prevalence for the shellfish allergy,” he says. The research study, led by McGill and McMaster University in Hamilton, was sponsored by Health Canada and AllerGen, a network of allergy experts and researchers. The telephone survey was conducted between 2008 and 2009 and included about 10,000 people.