Analysis of factors influencing sensitization of Japanese cedar pollen in asymptomatic subjects.

OBJECTIVE

Japanese cedar pollinosis is increasing rapidly in Japan. Although analysis has been made concerning the factors influencing the development of the cedar pollinosis, analysis concerning the risk factors influencing the sensitization in asymptomatic subjects has not been done.

METHODS

Risk factors for sensitization to Japanese cedar pollen were analyzed among 73 subjects (32 men and 41 women) who do not develop symptoms of pollinosis at the time of Japanese cedar pollen scattering. Their ages ranged from 18 to 60 years with the mean of 34.1 years. Possible factors influencing sensitization were investigated through a written questionnaire and doctors' questioning. Japanese cedar-specific IgE titers and Dermatophagoides pteronyssinus-specific IgE titers in the serum were measured by CAP-FEIA (fluorescent enzyme immunoassay).

RESULTS

Of the 73 subjects, 26 were sensitized to the Japanese cedar pollen, for a 36% sensitization rate. Among the eleven factors examined, only one factor was shown to significantly influence the sensitization rate to Japanese cedar pollen. It was sensitization to house dust mites (56.5% vs. 26.0% χ(2) value=6.27, p=0.012). The sensitization rate to the pollen did not correlate to the presence of other allergic diseases, history of rhinosinusitis, family history of Japanese cedar pollinosis, food preference, presence or absence of cedar trees in the surroundings, present living circumstances, childhood circumstances, age, sex, or smoking habits. We calculated odds ratios in order to estimate how much those factors influence the sensitization to Japanese cedar pollen. Significantly high odds ratio for sensitization to house dust mite (6.63; 95% confidence interval (CI): 1.76-32.2) was found.

CONCLUSION

The present study indicates that sensitization to the pollen in the subjects without pollinosis is influenced by sensitization to house dust mite.