Epidemiology of allergic rhinitis and its associated risk factors in Singapore

Few studies have evaluated the relationship between allergic rhinitis and risk factors in the environment which promote aeroallergenic exposures, but knowledge of these are of practical importance from the point of view of community prevention.

A cross-sectional population-based study of 2868 adults aged 20-74 years was carried out. Allergic rhinitis was defined as the self-reported presence, in the previous year, of usual nasal blockage and discharge apart from colds or the flu, provoked by allergens, with or without conjunctivitis.

Allergic rhinitis was reported by 4.5% of the subjects. Higher crude prevalences were observed in males, younger adults, Indians compared to Chinese and Malays, those with higher socioeconomic status, and in three of five residential areas studied. Significant environmental factors included cockroach infestation, occupational exposure, past smoking habit, outdoor air pollution, and frequent heavy exposure to cooking fumes. Keeping pets, having rugs or carpets in the home, and passive exposure to tobacco smoke showed weak and statistically insignificant associations. There was no apparent association with use of mosquito coils or incense. The significant determinants after multivariate adjustment of all risk factors were age, race, flat size, area of residence, cockroach infestation, past smoking, and occupational and cooking fumes exposure.

The study underscores the importance of environmental control of inhalational exposure to common allergens and irritants in the prevention of allergic rhinitis.