The Impact of Sex and Age on the Prevalence of Clinically Relevant Sensitization and Asymptomatic Sensitization in the General Population

Abstract

The objective of our study was to evaluate the impact of sex and age on the prevalence of sensitization to inhalant allergens. The study was performed as a part of Polish Epidemiology of Allergic Diseases study, and data concerning citizens of Wroclaw were analyzed. The participants were divided into three age groups (6-7, 13-14, and 20-44 years) with a subdivision according to sex. We randomly selected 1409 individuals, 439 people complied; the complete set of tests was performed on 421 of them. We found that 37.7 % of the study population demonstrated sensitization to at least one of the allergens tested. Positive skin tests were found more frequently in males than in females (p = 0.003); among 6-7-year-old children, the sensitization was independent of sex (p = 0.26), while in two other groups, it was higher in males (p = 0.002 and p = 0.03, respectively). Clinically asymptomatic sensitization (AS) was found more often in females than in males (p = 0.04). The higher rate of AS in women was observed only in the two younger age groups, while in the 20-44-year-old group AS did not differ between the sexes (p = 0.72). Female sex hormones may contribute to a later change in the nature of sensitization from clinically asymptomatic to symptomatic. Further studies are needed to confirm the results of our study.

Keywords: Asymptomatic sensitization; Population study; Total IgE; “Prick” skin test.

Fig. 1

Gender differences in the prevalence of positive skin tests. Wheal reactions with a mean diameter of 3 mm or more were regarded as positive if the control solutions showed the expected results (wheal size of at least 3 mm for the positive control and of less than 3 mm for the negative control)

Fig. 2

Gender differences in the prevalence of asymptomatic sensitization. Asymptomatic sensitization was defined as the presence of sIgE antibodies detectable in skin tests or serological tests in patients showing no clinical allergic symptoms to a specific allergen

Fig. 3

Gender differences in total IgE concentration

Fig. 4

Receiver operator characteristics (ROC) curve of total IgE (IU/mL): atopy vs nonatopy. On the basis of the receiver operator characteristics curve, a total IgE threshold of 79 IU/mL was adopted as the best differentiating value between people who are sensitized and non-sensitized, with 93 % specificity and 26 % sensitivity (area under the curve: 0.69)

Fig. 5

ROC (receiver operator characteristics) curve of total IgE (IU/mL): atopic and asymptomatic individuals vs atopic and symptomatic. The cut-off point of 14 IU/mL classified atopic individuals as asymptomatic or symptomatic with 57 % specificity and 78 % sensitivity (area under the curve: 0.65)