Exposure to Japanese Cedar Pollen in Early Life and Subsequent Sensitization to Japanese Cedar Pollen.

Abstract

The effect of exposure to Japanese cedar pollen (JCP) in early life on subsequent sensitization to it was evaluated. Specific IgE antibody to JCP was examined in 440-504 school children in a rural town each year during 1995-98. The amount of dispersed pollen measured by a Durham sampler widely ranged from 165 to 5941 grains/cm2/year during this period. The amount had been measured during the period of 1982-91 in which these children were born, and it also widely ranged from 148 to 8566 grains/cm2/year. Children born during November to January, who were exposed to JCP within 6 months of age, increased at the risk of sensitization to JCP, especially severe sensitization, relative to those born in the other months. Age-adjusted prevalence rate ratio (RR) of having a JCP-IgE*15 U/ml (control; <0.35 U/ml) for children born in December to February relative to children born in the other months was 1.74 (95% confidence interval; 1.06-2.87, examined in 1998), and for those born in November to January was 1.57 (95% CI; 1.00-2.46, examined in 1997). The risk of sensitization to JCP was low for those born in May to July (RR=0.42, 95%Cl; 0.19-0.93, examined in 1998). There was also a strong correlation between the amount of the dispersed pollen during the period of 2-6 months after birth and the prevalence of sensitization to JCP.

Aeroallergen sensitization and allergic disease phenotypes in Asia

“…34 Cedar pollen sensitization and allergic airway symptoms (termed cedar pollinosis) appeared to have a "cohort effect" in which the younger generations had a higher prevalence of pollinosis, possibly stemming from high exposures in early life which corresponded well with the environmental load. 35,36 Aeroallergen sensitization patterns in Africa, Europe and the Americas Different patterns of aeroallergen sensitization were seen in other parts of the world ( Table 2). [37][38][39][40][41][42][43][44][45][46][47] In West Africa (Nigeria and Ghana), high prevalences of cockroach sensitization were seen in asthmatic children and adolescents, and cat dander was also a more significant allergen than in Asia.…”

Prevalence and diversity of allergic rhinitis in regions of the world beyond Europe and North America

“…Several studies have documented the allergens/sensitizing agents and risk factors associated with the increased prevalence of AR and AR/C in the regions of interest .…”

“…Although the very large diversity and overlapping types of grass, tree and weed pollen makes it virtually impossible to assign specific plants as the main causes of AR in the different regions, it does nevertheless appear that Salsola and other weed pollen are particularly important sensitizing agents in the Middle East , where as cereal pollen appear to be important sensitizers in Turkey . Although, a large number of studies from Japan suggest Japanese cedar pollen to be possibly the most prevalent and important sensitizing agents across Japan , other studies have indicated that Japanese birch and cypress pollen are also important in different parts of Japan . Similarly, there is some evidence that sensitization to the non‐traditional silk/silk worm allergens may be important in the aetiology of AR particularly in China and Japan .…”

Japanese cedar pollen‐specific interleukin‐4 production develops immediately after the first exposure to pollens in infants with atopic dermatitis

“…Many investigators found that the incidence of pollenosis is high in individuals born in autumn or winter and low in those born in spring [15][16][17][18][19][20][21]. Although the cause of this phenomenon has not yet been clarified, the exposure to pollens before 6 months old is regarded as playing a critical role [20,21]. On the other hand, it is also noted that the incidence of AD is higher in infants born in autumn and winter in western countries as well as in Japan [22][23][24][25].…”