Unit of Pneumology, "Misericordia" Hospital, Grosseto, Italy.
Ann Thorac Med. 2012 Apr;7(2):61-8. doi: 10.4103/1817-1737.94521.
This study tried to evaluate whether a methacholine test may be influenced by the seasons.
We considered 4826 consecutive subjects with normal spirometry (50.53% males; age: 35.1±16.2; forced expiratory volume in one second: 99.5±13.0%) who underwent a methacholine test for suspected asthma symptoms between 2000 and 2010. They were subdivided into four groups, like the seasons, according to the test dates.
A total of 1981 (41%) resulted normal (no PD(20) was obtained with 2400 μg of methacholine); the others showed a mean LogPD(20) of 2.52±0.5 μg. The number of subjects with bronchial hyper-responsiveness (BHR) found in autumn (789, 62.3%) was higher than in summer (583, 56.7%; P=0.03). A higher number of females and overweight/obese subjects showed a BHR in autumn compared with the other seasons. The spring mean LogPD(20) value (2.48±0.48 μg) was lower if compared with the one measured in summer (2.59±0.49 μg; P=0.05). LogPD(20) value was lower in females and non-smokers in spring compared with summer (P<0.05). Overweight/obese non-smokers showed a lower LogPD(20) in spring and autumn compared with that in summer (P<0.05). Autumn was a risk factor (OR: 1.378; P=0.001) for BHR (using a PD(20) <2 400 μg as BHR limit), while spring (OR: 1.330; P=0.021) and autumn (OR: 1.331; P=0.020) were risk factors for a more severe BHR (using a PD(20) <400 μg as BHR limit).
There was a higher probability of finding BHR in outpatients with suspected asthma in autumn and spring compared with summer. Spring is the season where BHR may be more severe. Females and overweight/obese subjects were those mainly involved in this seasonal variability of BHR.
本研究旨在评估乙酰甲胆碱试验是否受季节影响。
我们纳入了 2000 年至 2010 年间因疑似哮喘症状接受乙酰甲胆碱试验的 4826 例肺功能正常的连续受试者（50.53%为男性；年龄：35.1±16.2 岁；第一秒用力呼气量：99.5±13.0%）。根据试验日期，他们被分为四组，类似于季节。
共有 1981 例（41%）结果正常（2400μg 乙酰甲胆碱时未获得 PD（20））；其余的平均 LogPD（20）为 2.52±0.5μg。秋季（789 例，62.3%）发现的支气管高反应性（BHR）患者多于夏季（583 例，56.7%；P=0.03）。与其他季节相比，秋季女性和超重/肥胖患者中 BHR 发生率更高。与夏季相比，春季的平均 LogPD（20）值（2.48±0.48μg）较低（P=0.05）。与夏季相比，春季女性和不吸烟者的 LogPD（20）值较低（P<0.05）。与夏季相比，超重/肥胖不吸烟者在春季和秋季的 LogPD（20）值较低（P<0.05）。秋季是 BHR 的危险因素（OR：1.378；P=0.001）（使用 PD（20）<2400μg 作为 BHR 界限），而春季（OR：1.330；P=0.021）和秋季（OR：1.331；P=0.020）也是 BHR 更严重的危险因素（使用 PD（20）<400μg 作为 BHR 界限）。
与夏季相比，秋季和春季疑似哮喘的门诊患者发生 BHR 的可能性更高。春季可能是 BHR 更严重的季节。女性和超重/肥胖患者是 BHR 这种季节性变化的主要参与者。
