Background

A high participation rate is warranted in order to ensure validity in surveys of the general population. However, participation rates in such studies have declined during the last decades.

Objective

To evaluate the reasons for and potential effects of non-response in a large population-based survey about asthma and respiratory symptoms in Northern Sweden.

Methods

Within the Obstructive Lung Disease In Norrbotten (OLIN) studies, a random sample of 12,000 adults aged 20–79 was invited to a postal questionnaire survey about asthma, allergic rhino-conjunctivitis and respiratory symptoms in 2016. Three reminders were sent. A random sample of 500 non-responders was invited to a telephone interview.

Results

The participation rate in the initial mailing was 41.4%, and 9.2%, 5.0%, and 2.6% in the subsequent three reminders and totally 58.3% (n = 6854) responded. Of 500 non-responders selected for telephone interviews, 320 were possible to reach and 272 participated. Male sex, younger age, and current smoking were associated with both late and non-response. The prevalence of asthma and most respiratory symptoms did not differ significantly between responders and non-responders while allergic rhino-conjunctivitis and smoking was more common among non-responders. Reminders increased the participation rate but did not alter risk ratios for smoking and occupational exposures. Reasons for non-response were mainly lack of time and having forgotten to answer.

Conclusions

With a response rate of 58.3%, neither the prevalence estimates of asthma, respiratory symptoms nor the associations to risk factors were affected, while allergic rhino-conjunctivitis and smoking was underestimated in this Swedish population.

中文翻译：

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无回应者不会影响哮喘和呼吸道症状的患病率估计-普通人群的邮政问卷调查结果

背景

为了确保在一般人群调查中的有效性，必须保证较高的参与率。但是，在过去的几十年中，此类研究的参与率有所下降。

目的

在瑞典北部有关哮喘和呼吸道症状的大规模人群调查中，评估无应答的原因和潜在影响。

方法

在Norrbotten的梗阻性肺疾病（OLIN）研究中，2016年随机抽取了12,000名20-79岁的成年人参加有关哮喘，过敏性鼻-结膜炎和呼吸道症状的邮政问卷调查。已发出三个提醒。随机抽取500名无应答者进行电话采访。

结果

初始邮件的参与率为41.4％，随后的三个提醒中的参与率为9.2％，5.0％和2.6％，总共有58.3％（n = 6854）得到了答复。在选择了500名未答复的电话采访中，有320名可以联系到272名参与者。男性，较年轻和目前吸烟与迟发和无反应有关。应答者和非应答者之间的哮喘患病率和大多数呼吸道症状没有显着差异，而过敏性鼻-结膜炎和吸烟在非应答者中更为常见。提醒提高了参与率，但没有改变吸烟和职业暴露的风险比。不回复的原因主要是时间不足，忘记了回答。

结论

瑞典人中有58.3％的缓解率对哮喘，呼吸道症状的流行率以及与危险因素的关联性都没有影响，而过敏性鼻-结膜炎和吸烟却被低估了。