Asthma control and cold weather-related respiratory symptoms.

BACKGROUND: In the northern hemisphere people are exposed recurrently to cold air and asthmatics experience more respiratory symptoms. We hypothesized that subjects with poor asthma control are more prone to experience cold weather-related respiratory symptoms than those with good asthma control. METHODS: A population-based cross-sectional study of 1995 adult asthmatics (response rate 40.4%) living in the Northern Finland was conducted using a questionnaire where cold weather-related respiratory symptoms as well as questions related to asthma control were inquired. The Asthma Control Test (ACT) was defined based on five questions (disadvantage and occurrence of asthma symptoms, waking up because of asthma symptoms, use of rescue medication and self-assessment of asthma control during the past 4 weeks), and was divided into quartiles. RESULTS: Cold weather-related respiratory symptoms were more frequent among asthmatics with poorly controlled asthma (ACT Q1 vs. ACT Q4); adjusted prevalence ratio (PR) for shortness of breath (men 1.47, 95% confidence interval 1.22-1.77; women 1.18, 1.07-1.30), cough (men 1.10, 0.91-1.34; women 1.18, 1.08-1.30), wheezing (men 1.91, 1.31-2.78; women 1.48, 1.17-1.87), phlegm production (men 1.51, 1.06-2.14; women 1.62, 1.27-2.08) and chest pain (men 4.47, 1.89-10.56; women 2.60, 1.64-4.12). The relations between asthma control and symptom occurrence seemed stronger among smokers than never smokers and subjects with body mass index (BMI) below and above 25-30. CONCLUSIONS: Our study provides new evidence that subjects whose asthma is poorly controlled are more prone to experience cold weather-related respiratory symptoms and even a slight worsening of asthma control increases symptom prevalences.

Asthma and allergic rhinitis increase respiratory symptoms in cold weather among young adults.

BACKGROUND: The occurrence of cold temperature-related symptoms has not been investigated previously in young adults, although cold weather may provoke severe symptoms leading to activity limitations, and those with pre-existing respiratory conditions may form a susceptible group. We tested the hypothesis that young adults with asthma and allergic rhinitis experience cold-related respiratory symptoms more commonly than young adults in general. METHODS: A population-based study of 1623 subjects 20-27 years old was conducted with a questionnaire inquiring about cold weather-related respiratory symptoms, doctor-diagnosed asthma and rhinitis, and lifestyle and environmental exposures. RESULTS: Current asthma increased the risk of all cold weather-related symptoms (shortness of breath adjusted PR 4.53, 95% confidence interval 2.93-6.99, wheezing 10.70, 5.38-21.29, phlegm production 2.51, 1.37-4.62, cough 3.41, 1.97-5.87 and chest pain 2.53, 0.82-7.79). Allergic rhinitis had additional effect especially on shortness of breath (7.16, 5.30-9.67) and wheezing (13.05, 7.75-22.00), some on phlegm production (3.69, 2.49-5.47), but marginal effect on cough and chest pain. INTERPRETATION: Our study shows that already in young adulthood those with asthma, and especially those with coexisting allergic rhinitis, experience substantially more cold temperature-related respiratory symptoms than healthy young adults. Hence, young adults with a respiratory disease form a susceptible group that needs special care and guidance for coping with cold weather.