Selection of study population.

<p>Patients without information on estimated exposure and presumed farmers were excluded only for logistic regression analyses with livestock exposure variables. EHRs, Electronic health records; IBD, Inflammatory bowel disease; NIVEL PCD, Netherlands Institute for Health Services Research Primary Care Database.</p

Associations between cat allergen concentrations in mattress dust and asthmatic and allergic respiratory symptoms.

<p>Fig 1 shows the associations between log-transformed cat allergen concentrations in mattress dust and asthmatic and allergic respiratory symptoms with approximate significance of the smooth terms</p

Associations between domestic cat allergen exposure and asthmatic and allergic respiratory symptoms stratified by community cat prevalence.

<p>Fig 2 shows the associations between log-transformed cat allergen concentrations in mattress dust and asthmatic and allergic respiratory symptoms with approximate significance of the smooth terms, stratified by community cat prevalence</p

Association between incidence of IBD and drug prescriptions in the reporting year and three previous years to the diagnosis^a.

<p>Association between incidence of IBD and drug prescriptions in the reporting year and three previous years to the diagnosis<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0195305#t004fn004" target="_blank">^a</a>.</p

Baseline characteristics of the study population (subset of ECRHS II).

<p>¹ Never had asthma and no lower respiratory symptoms (wheezing/whistling, tightness in chest, attack of shortness of breath during rest/activity, woken up by an attack of shortness of breath, asthma attack, medication), trouble with breathing, hay fever, runny or blocked nose without a cold, or medicine for breathing (last 12 months)</p><p>² exposure to second-hand smoke, smoke at home or during work</p><p>Baseline characteristics of the study population (subset of ECRHS II).</p

Characteristics of the study population.

<p>Characteristics of the study population.</p

Association in incident IBD patients between morbidity in the reporting year and three previous years to the diagnosis and farm animals ≤500m.

<p>Association in incident IBD patients between morbidity in the reporting year and three previous years to the diagnosis and farm animals ≤500m.</p

Associations between domestic cat allergen exposure and asthmatic and allergic respiratory symptoms stratified by geographical location.

<p>Fig 3 shows the associations between log-transformed cat allergen concentrations in mattress dust and asthmatic and allergic respiratory symptoms with approximate significance of the smooth terms, stratified by geographical location</p

Associations between spirometry-based COPD and potential risk factors and severity measures.

<p>COPD is defined on pre-and post-measurements and on LLN-definition and GOLD-definition.</p

Spirometry, questionnaire and electronic medical record based COPD in a population survey: Comparing prevalence, level of agreement and associations with potential risk factors

<div><p>Background</p><p>COPD-diagnosis is confirmed by post-bronchodilator (BD) spirometry. However, epidemiological studies often rely on pre-BD spirometry, self-reports, or medical records. This population-based study aims to determine COPD-prevalence based on four different operational definitions and their level of agreement, and to compare associations between COPD-definitions and risk factors.</p><p>Methods</p><p>COPD-prevalence in 1,793 adults from the general Dutch population (aged 18–70 years) was assessed based on self-reported data, Electronic Medical Records (EMR), and post-BD spirometry: using the FEV1/FVC below the lower limit of normal (LLN) and GOLD fixed cut-off (FEV1/FVC <0.70). Using spirometry as a reference, sensitivity was calculated for self-reported and EMR-based COPD. Associations between COPD and known risk factors were assessed with logistic regression. Data were collected as part of the cross-sectional VGO study (Livestock Farming and Neighboring Residents’ Health Study).</p><p>Results</p><p>The highest prevalence was found based on spirometry (GOLD: 10.9%, LLN: 5.9%), followed by self-report (4.6%) and EMR (2.9%). Self-reported or EMR-based COPD identified less than 30% of all COPD-cases based on spirometry. The direction of association between known risk factors and COPD was similar across the four definitions, however, magnitude and significance varied. Especially indicators of allergy were more strongly associated with self-reported COPD compared to the other definitions.</p><p>Conclusions</p><p>COPD-prevalence varied depending on the used definition. A substantial number of subjects with spirometry-based COPD cannot be identified with questionnaires or medical records which can cause underestimation of COPD-prevalence. The influence of the different COPD-definitions on associations with known risk factors was limited.</p></div