To determine the prevalence of self-reported peanut and tree-nutallergy among the general population of the United States in2002 and compare it with prevalence rates obtained 5 years earlier.
A nationwide, cross-sectional survey was administered by telephoneto persons called by a random sampling of telephone numbersin the continental United States. Adults acted as surrogatesfor minors with peanut or tree-nut allergy. Differences in responsesbetween groups were tested by 2 analysis.
Fifty-three percent of contacted homes participated. Peanutallergy, tree-nut allergy, or both was self-reported in 166(1.2%; 95% confidence interval [CI]: 1.0%, 1.4%) individualsin 155 (3.2%; 95% CI: 2.7%, 3.7%) households. These prevalencerates were similar to those reported in 1997. Any differencesin prevalence rates between people of different race/ethnicitydid not reach statistical significance. There was an overallmale predominance of peanut or tree-nut allergy in children(P = .02) and a female predominance in adults (P = .0008). Theprevalence of reported peanut allergy among children increasedsignificantly from 0.4% in 1997 to 0.8% in 2002 (P = .05), butthe rate of tree-nut allergy did not change significantly. Theprevalence of peanut and tree-nut allergy in adults did notchange significantly between 1997 and 2002. Overall, the adjustedprevalence rate taking into account individuals with reportedallergy without convincing histories was 1.04% (95% CI: 0.9%,1.2%). Of the reported reactions, 79% involved either respiratorysymptoms or multiple organ systems. Only 74% of children and44% of adults were evaluated by a physician for their allergicreactions, and self-injectable epinephrine was prescribed for46% of the children and 23% of the adults.
The authors reported similar overall rates of peanut and tree-nutallergy in the United States, as was noted in 1997, but overthis 5-year period the prevalence of peanut allergy in childrendoubled.
The findings of increased prevalence of peanut allergy may beexpected with the well-documented increase of atopic diseasesin the past decades. Why the prevalence of tree-nut allergywould be unchanged during this same period will require additionalinvestigation. A notable finding in this study is that >25%of children and 50% of adults who reported peanut or tree-nutallergy did not seek medical evaluation. Even more remarkableis that after medical evaluation for peanut or tree-nut allergy,self-injectable epinephrine was prescribed to approximatelyhalf of the children and less than one quarter of the adults.This underscores the need for continued improvement in the careof patients with food allergy, which is increasing in prevalence.