Characterization of chronic itch in college students in China

Background Chronic itch affects a et al. range of individuals and has a noticeable influence on human health. However, epidemiological characteristics of chronic itch have not yet been adequately addressed. Objectives To investigate the prevalence and associated factors for chronic itch. Materials & Methods This was a cross-sectional study of first-year students in five universities in different regions of China. Chronic itch was defined as moderate-to-severe itch for more than six weeks. Social and behavioural factors were measured through an online questionnaire survey. Environmental factors including humidity, temperature and levels of air pollutants at district/county level were obtained from public datasets. Generalized linear-mixed models were used to fit multi-level data. Results A total of 27,144 students were enrolled to the universities and 18,360 subjects who completed the survey were included in the final analysis. The mean age of participants was 18.3 ± 0.8 years, and 51.1% were women. The point prevalence of chronic itch was 16.9%. Chronic itch was associated with female sex (OR = 0.78, p < 0.001) and was inversely associated with higher parental educational levels. With respect to environmental factors, chronic itch was significantly associated with relative humidity (OR=1.01, p = 0.02), temperature (OR =1.03, p <0.001) and O 3 (OR = 0.91, p < 0.001). Regarding behavioural factors, chronic itch was significantly associated with smoking, exposure to second-hand smoke, drinking alcohol, less physical activity, intake of pepper, preference for spicy food, bathing (temperature, frequency, and duration) and sunscreen. Conclusion Chronic itch affects a substantial proportion of Chinese college students, and is attributable to demographic, dermatological, environmental and behavioural factors.