BACKGROUND:Earlychildhoodfeversappear to protect against laterallergiesandasthma. What is not known is the time in whichfeversexert this effect and whether the degree of temperature increase is important.OBJECTIVE:We sought to examine the relationship between the time and degree ofearlyfeversand laterallergiesandasthma.METHODS:Eight hundred thirty-five children from southeast Michigan were enrolled at birth. Clinic records from their first 2 years were abstracted for episodes of fever. At age 6 to 7 years, children underwent allergy testing. We examinedfeversoccurring within 6-month intervals in the first 2 years of life and outcomes at age 6 to 7 years. The primary outcome measures were allergic sensitization,asthma,asthmawith allergic sensitization, andasthmawithout allergic sensitization.RESULTS:In the unadjusted analysis each episode of fever between 7 and 12 months of age was associated with a lower odds of allergic sensitization (odds ratio [OR], 0.71; 95% CI, 0.54-0.93) andasthmawith allergic sensitization (OR, 0.43; 95% CI, 0.21-0.90) at age 6 to 7 years. Likewise, every 1 degrees C increase in the maximum temperature between 7 and 12 months was associated with a lower odds of allergic sensitization (OR, 0.77; 95% CI, 0.61-0.96) andasthmawith allergic sensitization (OR, 0.62; 95% CI, 0.40-0.94). After adjusting for potential confounders, each episode of fever between 7 and 12 months was associated with a lower likelihood ofasthmawith allergic sensitization (adjusted OR, 0.33; 95% CI, 0.11-0.94) at age 6 to 7 years.CONCLUSIONS:Both thetimingandintensityof childhoodfeversappear to be important factors in thedevelopmentofallergiesandasthma.
