Is allergen skin test reactivity a predictor of mortality? Findings from anational cohort

Background The importance of atopy on subsequent mortality is controversial . A clearer understanding is important as atopy is increasing worldwide. Objective To determine the influence of allergen skin test reactivity on ob served mortality of a national cohort. Methods Baseline health status and atopic status (allergen skin testing) wa s measured as part of the second National Health and Nutrition Examination Survey (NHANES II), a representative sample of the US population, during th e years 1976-80. Vital status and cause of death were assessed through Dece mber 31, 1992 for all examinees 30 years of age or older at baseline (n = 9 252) as part of the NHANES II Mortality Study (NH2MS). The analytic sample contained 8179 men and women after excluding missing data. Allergen skin te st reactivity was defined as weal greater than or equal to 3 mm to one of e ight 1 : 20 (w/v), 50% glycerinated ('No US Standard of Potency') allergens licensed by the FDA: house dust, cat, dog, Alternaria, mixed giant/short r agweed, oak, perennial rye grass, and Bermuda grass. Survival analyses were conducted using multivariate adjusted Cox regression models to evaluate th e association between atopy and all-cause, cardiovascular, and cancer morta lity. Results There was no association between allergen skin test reactivity and all cause mortality: 30-44 years RR = 1.07 (95% CI 0.63-1.84); 45-59 years RR = 1.10 (0.78-1.55); 60-75 years RR = 1.07 (0.91-1.25). Results were unch anged when cancer or heart disease mortality were examined separately. The presence or absence of allergic symptoms, using the flare to define skin te st reactivity, eliminating deaths in the first 5 years of follow-up, or eli minating individuals with pre-existing conditions did not alter the finding s. Conclusions Atopy, defined by allergen skin test reactivity, with or withou t symptoms, is not a predictor of subsequent mortality.