Table 1

Comparison of the 6-year cohort and the baseline study population, Espoo, Finland 1991–1997.

Baseline
 Lost to follow-up
 6-year-cohort
Characteristics at baseline
 N
 %
 N
 %
 N
 %
Number
 2568
 100
 584
 22.7
 1984
 77.3







Age (years)





     1
 424
 16.5
 100
 17.1
 324
 16.3
     2
 405
 15.8
 104
 17.8
 301
 15.2
     3
 310
 16.0
 92
 15.8
 318
 16.0
     4
 400
 15.6
 67
 11.5
 333
 16.8
     5
 415
 16.2
 101
 17.3
 314
 15.8
     6
 391
 15.2
 81
 13.9
 310
 15.6
     7-
 123
 4.8
 39
 6.7
 84
 4.2
Gender





     Boy
 1310
 51.0
 309
 52.9
 1001
 50.5
     Girl
 1258
 49.0
 275
 47.1
 983
 49.5
Any allergic disease





     Yes
 337
 13.1
 81
 13.9
 256
 12.9
     No
 2231
 86.9
 503
 86.1
 1728
 87.1
Single parent/guardian





     Yes
 183
 7.1
 53
 9.1
 130
 6.6
     No
 2385
 92.9
 531
 90.9
 1854
 93.4
Highest level of parental education





     Non-professional
 498
 19.5
 129
 22.3
 369
 18.7
     Trade school
 663
 25.9
 140
 24.2
 523
 26.5
     College or university
 1395
 54.6
 310
 53.5
 1085
 54.9
     Missing information
 12




Exposure to ETS





     Yes
 267
 10.4
 76
 13.1
 191
 9.7
     No
 2291
 89.6
 504
 86.9
 1787
 90.3
     Missing Information
 10




Gas stove





     Yes
 86
 3.4
 24
 4.1
 62
 3.1
     No
 2469
 96.6
 556
 95.9
 1913
 96.9
     Missing Information
 13




Hairy/Feathery Pets





     Yes
 480
 18.7
 113
 19.3
 367
 18.5
     No
 2088
 81.3
 471
 80.7
 1617
 81.5
Type of day care





     100% Home
 940
 36.6
 210
 36.0
 730
 36.8
     100% Family
 513
 20.0
 119
 20.4
 394
 19.9
     100% Centre
 252
 9.8
 56
 9.6
 196
 9.9
     Combinations
 863
 33.6
 199
 34.1
 664
 33.5

Fredriksson et al. BMC Pediatrics 2007 7:39   doi:10.1186/1471-2431-7-39