Cold weather increases respiratory symptoms and functional disability especially among patients with asthma and allergic rhinitis.

Cold weather affects the respiratory epithelium and induces bronchial hyperresponsiveness. We hypothesized that individuals with allergic rhinitis or/and asthma experience cold weather-related functional disability (FD) and exacerbation of health problems (EH) more commonly than individuals without these. This was a population-based study of 7330 adults aged 25-74 years. The determinants of interest, including doctor-diagnosed asthma and allergic rhinitis, and the outcomes, including cold weather-related FD and EH, were measured using a self-administered questionnaire. The prevalences of cold-related FD and EH were 20.3% and 10.3%, respectively. In Poisson regression, the risk of FD increased in relation to both allergic rhinitis (adjusted prevalence ratio (PR) 1.19, 95% CI 1.04-1.37 among men; 1.26, 95% CI 1.08-1.46 among women), asthma (1.29, 0.93-1.80; 1.36, 0.92-2.02, respectively) and their combination (1.16, 0.90-1.50; 1.40, 1.12-1.76, respectively). Also the risk of cold weather-related EH was related to both allergic rhinitis (1.53, 1.15,-2.04 among men; 1.78, 1.43-2.21 among women), asthma (4.28, 2.88-6.36; 3.77, 2.67-5.34, respectively) and their combination (4.02, 2.89-5.59; 4.60, 3.69-5.73, respectively). We provide new evidence that subjects with allergic rhinitis or/and asthma are more susceptible to cold weather-related FD and EH than those without pre-existing respiratory diseases.