Sensitisation to natural rubber latex: an epidemiological study of workersexposed during tapping and glove manufacture in Thailand

Objectives-To estimate the prevalence of sensitisation to natural rubber la tex in latex tappers and latex glove factory workers, and to relate this to airborne exposure to latex. Methods-Five hundred workers employed in three latex glove factories, 314 t appers, and 144 college students (control group) were studied. The workers in the glove factories were classified into three exposure groups; high, mo derate, and low. Personal exposures to natural rubber latex aeroallergens w ere measured by immunoassay. Symptom questionnaires and skin prick tests wi th latex allergens (Stallergenes 1:200 w/v) and other common environmental allergens were performed. The criterion for positivity was a wheal reaction at least 3 mm in diameter greater than that to a diluent control. Results-The geometric mean (GM) concentration of latex in air was 15.4 mug/ m(3) for those employed in glove stripping, glove inspections, and packing of powdered gloves. The moderate exposure glove manufacturing group and the tappers had GM concentrations of 2.3 and 2.4 mug/m(3) respectively, compar ed with United Kingdom users of latex powdered gloves,who had GM concentrat ions of 0.5 mug/m(3). The prevalence of sensitisation to latex in the tappe rs and latex glove factory workers was 1.3% and 1.7% respectively. No posit ive cases were found among the college students. Workers who showed a posit ive skin prick test to latex were more likely to be atopic. Work related re spiratory and dermatological symptoms were found in about 20% of each popul ation studied, but were not related to the presence of positive latex prick tests. Conclusions-This study suggests that in the Thai latex industries, latex se nsitisation is rare despite high concentrations of airborne exposure and is less prevalent than in the healthcare sector in Europe where skin exposure is greater.