Abstract：
OBJECTIVE: Exercise test outdoors is widely used to diagnose asthma in children, but it is unclear how much outdoor air factors affect the results.
METHODS: We analysed 321 outdoor exercise challenge tests with spirometry in children 6-16 years conducted due to suspicion of asthma or for assessing the effect of medication on asthma. We studied the association of FEV1 decrease and incidence of exercise-induced bronchoconstriction (EIB) with temperature, relative humidity (RH) and absolute humidity (AH).
RESULTS: Asthma was diagnosed in 57% of the subjects. AH ≥5 g/m3, but not RH or temperature, was associated with the EIB incidence (p = 0.035). In multivariable logistic regression, AH ≥5 g/m3 was negatively associated (OR = 0.51, 95% CI [0.28─0.92], p = 0.026) while obstruction before exercise (OR = 2.11, 95% CI [1.16─3.86], p = 0.015) and IgE-mediated sensitisation were positively associated with EIB (OR = 2.24, 95% CI [1.11─4.51], p = 0.025). AH (r = -0.12, p = 0.028) and temperature (r = -0.13, p = 0.023) correlated with decrease in FEV1. In multivariable linear regression, only AH was associated with FEV1 decrease (coefficient = -0.044, 95% CI [-0.085 to -0.004], p = 0.033).
CONCLUSIONS: AH of outdoor air associates with occurrence and severity of EIB in outdoor exercise tests in children. Care should be taken when interpreting negative outdoor exercise test results if AH of air is high.
METHODS: We analysed 321 outdoor exercise challenge tests with spirometry in children 6-16 years conducted due to suspicion of asthma or for assessing the effect of medication on asthma. We studied the association of FEV1 decrease and incidence of exercise-induced bronchoconstriction (EIB) with temperature, relative humidity (RH) and absolute humidity (AH).
RESULTS: Asthma was diagnosed in 57% of the subjects. AH ≥5 g/m3, but not RH or temperature, was associated with the EIB incidence (p = 0.035). In multivariable logistic regression, AH ≥5 g/m3 was negatively associated (OR = 0.51, 95% CI [0.28─0.92], p = 0.026) while obstruction before exercise (OR = 2.11, 95% CI [1.16─3.86], p = 0.015) and IgE-mediated sensitisation were positively associated with EIB (OR = 2.24, 95% CI [1.11─4.51], p = 0.025). AH (r = -0.12, p = 0.028) and temperature (r = -0.13, p = 0.023) correlated with decrease in FEV1. In multivariable linear regression, only AH was associated with FEV1 decrease (coefficient = -0.044, 95% CI [-0.085 to -0.004], p = 0.033).
CONCLUSIONS: AH of outdoor air associates with occurrence and severity of EIB in outdoor exercise tests in children. Care should be taken when interpreting negative outdoor exercise test results if AH of air is high.
摘要：
目的：户外运动试验广泛用于诊断儿童哮喘，但目前尚不清楚室外空气因素对结果有多大影响。
方法：我们对怀疑哮喘或评估药物对哮喘的影响的6-16岁儿童进行了321项室外运动挑战测试和肺活量测定。我们研究了FEV1下降和运动引起的支气管收缩（EIB）的发生率与温度的关系，相对湿度（RH）和绝对湿度（AH）。
结果：57%的受试者被诊断为哮喘。AH≥5g/m3，但不包括RH或温度，与EIB发生率相关(p=0.035)。在多变量逻辑回归中，AH≥5g/m3呈负相关(OR=0.51，95%CI[0.28─0.92]，p=0.026)，而运动前梗阻(OR=2.11，95%CI[1.16─3.86]，p=0.015）和IgE介导的致敏与EIB呈正相关（OR=2.24，95％CI[1.11─4.51]，p=0.025)。AH（r=-0.12，p=0.028）和温度（r=-0.13，p=0.023）与FEV1的降低相关。在多元线性回归中，只有AH与FEV1下降相关(系数=-0.044，95%CI[-0.085至-0.004]，p=0.033)。
结论：室外空气的AH与儿童户外运动试验中EIB的发生和严重程度相关。如果空气的AH很高，在解释负面的户外运动测试结果时应格外小心。
方法：我们对怀疑哮喘或评估药物对哮喘的影响的6-16岁儿童进行了321项室外运动挑战测试和肺活量测定。我们研究了FEV1下降和运动引起的支气管收缩（EIB）的发生率与温度的关系，相对湿度（RH）和绝对湿度（AH）。
结果：57%的受试者被诊断为哮喘。AH≥5g/m3，但不包括RH或温度，与EIB发生率相关(p=0.035)。在多变量逻辑回归中，AH≥5g/m3呈负相关(OR=0.51，95%CI[0.28─0.92]，p=0.026)，而运动前梗阻(OR=2.11，95%CI[1.16─3.86]，p=0.015）和IgE介导的致敏与EIB呈正相关（OR=2.24，95％CI[1.11─4.51]，p=0.025)。AH（r=-0.12，p=0.028）和温度（r=-0.13，p=0.023）与FEV1的降低相关。在多元线性回归中，只有AH与FEV1下降相关(系数=-0.044，95%CI[-0.085至-0.004]，p=0.033)。
结论：室外空气的AH与儿童户外运动试验中EIB的发生和严重程度相关。如果空气的AH很高，在解释负面的户外运动测试结果时应格外小心。
