Table 3

Mode of participation and reason for non-participation among controls, Brain Tumour case-control study 2000–2002, Sweden.

Participants (n=673)Non-participants (n=268)
Personal interview no. (%)Telephone interview no. (%)Written questionnaire no. (%)p Value*Refusal no. (%)Failure of contact no. (%)p Value
Sex0.00020.17
 Women297 (83)31 (9)29 (8)92 (66)47 (34)
 Men295 (93)9 (3)12 (4)75 (58)54 (42)
Age1.00.002
 20–39114 (87)8 (6)9 (7)30 (45)37 (55)
 40–49110 (87)8 (6)8 (6)27 (57)20 (43)
 50–59197 (88)13 (6)13 (6)59 (71)24 (29)
 60–171 (89)11 (6)11 (6)51 (72)20 (28)
Marital status0.007<0.0001
 Single128 (91)5 (4)7 (5)35 (45)42 (55)
 Married355 (90)17 (4)24 (6)99 (78)28 (22)
 Divorced90 (82)11 (10)9 (8)22 (45)27 (55)
 Widowed15 (75)5 (25)08 (80)2 (20)
 Unknown42132
Education0.160.23
 Compulsory112 (85)8 (6)12 (9)53 (67)26 (33)
 Secondary school
 ≤2 years185 (86)14 (6)17 (8)50 (58)36 (42)
 3 years91 (88)7 (7)5 (5)30 (75)10 (25)
 Higher education197 (93)9 (4)6 (3)30 (59)21 (41)
 Unknown72148
Working status0.0030.09
 Not working154 (82)19 (10)15 (8)65 (57)50 (43)
 Working434 (91)19 (4)25 (5)99 (67)49 (33)
 Unknown42132
Socioeconomic status0.510.31
 Manual workers161 (87)10 (5)14 (8)57 (71)23 (29)
 Non-manual employees281 (91)16 (5)13 (4)57 (74)20 (26)
 Employees - not classified37 (92)2 (5)1 (2)5 (50)5 (50)
 Self-employed15 (83)1 (6)2 (11)8 (89)1 (11)
 Unknown9811114052
Income§0.020.03
 <110000116 (83)9 (6)15 (11)51 (51)49 (49)
 110000–150000144 (88)12 (7)8 (5)57 (68)27 (32)
 >150000–190000153 (86)12 (7)12 (7)28 (74)10 (26)
 >190000175 (95)5 (3)5 (3)28 (68)13 (32)
 Unknown42132
  • * p Value for difference among participants.

  • p Value for difference among non-participants.

  • Based on occupation and type of employment in the census 1990.

  • § Swedish kronor (SEK), individual disposable income.