Table 2

 Prevalence of respiratory symptoms in 1557 farmers who responded early, and in 346 farmers who returned a questionnaire after the telephone reminder or answered a few questions by telephone (late-response group)

Early responseLate responseLate response*Late response†
ECRHS, European Community Respiratory Health Survey.
p>0.1 for all symptoms; χ2 test.
Values are expressed in percentage.
*Weighted for proportion of organic farmers in early-response group.
†Weighted for proportion of livestock farmers in early-response group.
Daily cough up phlegm8.69.09.19.4
Woken due to shortness of breath2.13.23.62.4
Wheezing11.511.111.810.0
Episode of asthma last year1.82.12.41.6
Use of drugs for asthma3.24.14.13.5
Asthma (ECRHS)4.65.96.24.4
Any allergy24.025.825.425.1
Hay fever7.67.97.87.5