Table 1

Flow scheme of participation in the study

	n	Drop out^1-150	Missing^1-151
Total study population	259
Baseline questionnaire	239
Symptom questionnaire:
R1	241
R2	163	27	51
R3	188	26
Clinical examination:
R1	243
R2	158	57	28
R3	135	51

↵1-150 Drop out=subjects who left the study.
↵1-151 Missing=subjects who were absent at R2 only.
R1=baseline; R2=1 year follow up; R3=2 years follow up.