Factors N in group % with OFP RR (95% CI) adjusted
for age and gender 		RR (95% CI) adjusted for age,
gender, deprivation,
pain in the body,
psychological distress
Information from Questionnaire
Self-reported extractions
Third molars not removed 866 17.4 1.00 1.00
Third molars removed 556 22.8 1.38 (1.08 - 1.76) 1.29 (1.01 - 1.65)
Missing data 88
Information from Dental records
Extractions
All third molars present 130 19.2 1.00 1.00
At least one third molar extracted 151 27.8 1.50 (0.91 - 2.48) 1.50 (0.90 - 2.49)
No information on extraction in record
or missing questionnaire data		 528
Time since most recent extraction
All third molars present 130 19.2 1.00 1.00
Extraction 2 - 99 months agoa 72 37.5 1.95 (1.12 - 3.37) 1.91 (1.10 - 3.32)
Extraction 100 - 558 months ago 73 17.8 0.99 (0.50 - 1.95) 1.07 (0.54 - 2.13)
No information on date of extraction 6
Number of third molars present
All 4 present 130 19.2 1.00 1.00
3 112 22.3 1.27 (0.73 - 2.21) 1.24 (0.71 - 2.16)
2 145 20.7 1.13 (0.66 - 1.93) 1.03 (0.60 - 1.78)
1 139 23.0 1.32 (0.83 - 2.11) 1.29 (0.76 - 2.20)
All absent 252 24.6 0.96 (0.63 - 1.45) 1.19 (0.74 - 1.90)
Information missing
on at least one third molar		 28
No information on OFP 3

a100 months was a median time since extraction and therefore was chosen as a cut-off point.
No participants had extraction less than 2 month prior to questionnaire completion.