Centre for Public Health Research, Massey University Wellington Campus, Wellington, New Zealand.
Respirology. 2013 Jul;18(5):857-65. doi: 10.1111/resp.12079.
Increased sputum neutrophilia has been observed in asthma, but also during normal ageing in asthmatics and non-asthmatics. It remains unclear what constitutes 'normal' neutrophil levels in different age groups.
We assessed the relationship between age and airway neutrophils of 194 asthmatics and 243 non-asthmatics (age range: 6-80 years). Regression analyses were used to assess this relationship adjusted for confounders including asthma status, atopy, gender, smoking and current use of inhaled corticosteroids (ICS). Age-corrected reference values for different age groups were determined using the 95th percentile of non-asthmatic participants.
Age was positively associated with sputum neutrophils in both asthmatic and non-asthmatic adults (0.46% neutrophil increase/year (95% confidence interval (CI) 0.18, 0.73) and 0.44%/year (0.25, 0.64, respectively), but no association was found in the <20-year age category. Individuals with high sputum neutrophil counts (>95th percentile of non-asthmatic counts for any given age group) were significantly more likely to be asthmatic (odds ratio = 2.5; 95% CI: 1.3, 5.0), with the greatest effect observed in the older age group. Other factors that independently associated with increased sputum neutrophil levels included atopy in non-asthmatic adults, male gender and current use of ICS in asthmatic adults. Age-specific reference values for neutrophil percentage were under 20 years-76%, 20-40 years-62%, 40-60 years-63% and over 60 years-67%.
Airway neutrophilia is related to age in adults, with a neutrophilic asthma phenotype present in older adults. The use of appropriate age-specific reference values is recommended for future studies aimed at elucidating the role of neutrophils in asthma.
在哮喘患者中观察到痰液中性粒细胞增多，但在哮喘患者和非哮喘患者的正常衰老过程中也观察到这种现象。目前尚不清楚不同年龄组中“正常”中性粒细胞水平是多少。
我们评估了 194 名哮喘患者和 243 名非哮喘患者（年龄范围：6-80 岁）的年龄与气道中性粒细胞之间的关系。采用回归分析调整了哮喘状态、过敏、性别、吸烟和吸入性皮质类固醇（ICS）的当前使用等混杂因素，评估了这种关系。使用非哮喘参与者的第 95 百分位数确定了不同年龄组的年龄校正参考值。
年龄与哮喘患者和非哮喘患者的痰液中性粒细胞均呈正相关（每年中性粒细胞增加 0.46%（95%置信区间（CI）0.18，0.73）和 0.44%/年（0.25，0.64），但在<20 岁年龄组中未发现这种关联。痰液中性粒细胞计数较高（任何给定年龄组的非哮喘计数的第 95 百分位数以上）的个体更有可能患有哮喘（比值比=2.5；95%CI：1.3，5.0），在年龄较大的年龄组中观察到的效果最大。其他与痰液中性粒细胞水平独立相关的因素包括非哮喘患者的过敏、男性性别和哮喘患者的 ICS 目前使用。年龄特异性中性粒细胞百分比参考值为<20 岁-76%、20-40 岁-62%、40-60 岁-63%和>60 岁-67%。
在成年人中，气道中性粒细胞与年龄有关，在老年成年人中存在中性粒细胞哮喘表型。建议在未来旨在阐明中性粒细胞在哮喘中的作用的研究中使用适当的年龄特异性参考值。
