Seasonal dynamics of cold airway hyperresponsiveness in patients with asthma

Abstract

Introduction. Cold air-induced bronchoconstriction in patients with asthma, leading to a breakdown in disease control, is one of the most serious problems in the northern countries of the world.Aim. To assess the seasonal dynamics of the airway response (ΔFEV1CA) to cold bronchoprovocation in asthma patients with cold airway hyperresponsiveness (CAHR).Materials and methods. Out of 513 asthma patients who underwent primary bronchoprovocation testing, 273 patients (140 women; 133 men) with diagnosed CAHR took part in the retrospective analysis. The design objectification of clinical data using the Asthma Control Test questionnaire (ACT, Quality Metric Inc., 2002), a screening questionnaire for identifying clinical symptoms of response to low ambient temperature in everyday life; assessment of the lung function; bronchoprovocation test of 3-minute isocapnic hyperventilation with cold (-20ºC) air (IHCA).Results. At the time of testing, the average age of patients was 34.8±0.87 years, FEV1 88.5±1.3% of predicted, FEV1/VC 70.9±0.7%; ACT 16 (12; 19) points. On average in the group, ΔFEV1CA was -19.2±0.6%. The frequency of CAHR detection in the winter was 22%, spring – 34%, summer – 22%, autumn – 24% (p>0.05). The minimum changes in FEV1 in response to IHCA were recorded in May-June (mean value ΔFEV1CA -16.2±1.3 and -14.5±1.6%, respectively) and were significantly less in comparison with February (-21.9±2.3%, p˂0.05) and April (-23.0±2.36%, p˂0.01). A correlation has been found between the monthly mean values of meteorological parameters and CAHR, as well as the value of ACT in points and ΔFEV1 (r=0.16; p=0.018).Conclusion. Seasonal changes in the strength of the action of meteorological factors produce a change in the response of the airways to cold bronchoprovocation, and contribute to the loss of asthma control. The maximum values of CAHR fall on February-April, August, November. The data obtained reflect the presence of a complex interaction of physical environmental factors in the induction of seasonal fluctuations of CAHR, which requires a search for specific mechanisms for the formation of altered airway reactivity associated with the characteristics of molecular reception of low temperatures and humidity in the human airways.