Effect of grain exposure and smoking on the longitudinal changes in immediate skin reactivity

The study was carried out to investigate the effect of occupational exposure and smoking on the longitudinal changes of immediate skin reactivity over 3 years in working populations. A total of 480 grain elevator workers and 707 transit and ferry (control) workers were included because they had allergy skin tests on both surveys. Skin-prick texts using three common allergens and a negative and histamine controls were administered during both surveys. The reaction was considered positive if the mean weal size was 3 mm or greater than that of the negative control. Conversion was defined as a change from the non-atopic state in the initial survey to the atopic state in the follow-up survey. Reversion was defined as a change from the atopic state in the initial survey to the non-atopic state in the follow-up survey. The findings showed that grain workers had two times risk of conversion than control workers. Recent smokers, who changed their habit from non-smoker/ex-smoker to smoker in the follow-up survey, were at a three times risk of conversion than non-smokers. The reversion of skin-test reactivity was not associated with age, smoking habits, or working exposure. When investigating studies of longitudinal changes in immediate skin reactivity, the effects of age, changes in smoking habit and occupational exposure should be considered.