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

The importance of atopy on subsequent mortality is controversial. A clearer understanding is important as atopy is increasing worldwide.

To determine the influence of allergen skin test reactivity on observed mortality of a national cohort.

Baseline health status and atopic status (allergen skin testing) was measured as part of the second National Health and Nutrition Examination Survey (NHANES II), a representative sample of the US population, during the years 1976-80. Vital status and cause of death were assessed through December 31, 1992 for all examinees 30 years of age or older at baseline (n = 9252) as part of the NHANES II Mortality Study (NH2MS). The analytic sample contained 8179 men and women after excluding missing data. Allergen skin test reactivity was defined as weal >/= 3 mm to one of eight 1 : 20 (w/v), 50% glycerinated ('No US Standard of Potency') allergens licensed by the FDA: house dust, cat, dog, Alternaria, mixed giant/short ragweed, oak, perennial rye grass, and Bermuda grass. Survival analyses were conducted using multivariate adjusted Cox regression models to evaluate the association between atopy and all-cause, cardiovascular, and cancer mortality.

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 unchanged when cancer or heart disease mortality were examined separately. The presence or absence of allergic symptoms, using the flare to define skin test reactivity, eliminating deaths in the first 5 years of follow-up, or eliminating individuals with pre-existing conditions did not alter the findings.

Atopy, defined by allergen skin test reactivity, with or without symptoms, is not a predictor of subsequent mortality.