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Table 1 Comparison of basic data collected in CLARITY cases and controls

From: CLARITY – ChiLdhood Arthritis Risk factor Identification sTudY

  All cases Victorian-born cases Victorian-born (all) controls
  n†   n†   n†  
Basic characteristics       
Child mean age at interview 262 9.5 (SD: 4.5)* 229 9.4 (SD: 4.6)* 458 7.1 (SD 4.2)
Child female 262 67.2%* 229 68.1%* 458 39.7%
Child has four Caucasian grandparents 217 87.1%* 190 90.0%* 378 79.1%
Mother’s age at interview 256 40.3 (SD: 6.0)* 224 40.5 (SD: 5.8)* 449 36.9 (SD: 6.4)
Father’s age at interview 243 43.0 (SD: 6.6)* 213 43.2 (6.5)* 398 39.4 (SD: 6.8)
Socio-demographic data       
Mother’s SEIFA§ score 90 1026.7 (SD: 62.9)* 74 1030.9 (SD: 62.6)* 305 1003.7 (SD: 70.4)
Father’s SEIFA§ score 81 1026.1 (SD: 64.3)* 67 1033.6 (SD: 61.7)* 245 1006.5 (SD: 71.7)
Mother’s education       
 Completed year 12 257 66.2% 224 68.8% 449 71.9%
 Completed postgraduate degree 202 10.4% 173 10.4% 344 10.8%
Father’s education       
 Completed year 12 244 57.4% 215 57.7% 399 61.4%
 Completed postgraduate degree 180 12.8% 157 12.7% 275 9.8%
Mother’s marital status at interview 256   223   450  
 married   79.3%*   80.7%*   70.9%
 divorced   7.0%   7.2%   6.2%
 separated   5.1%   4.9%   6.2%
 widowed   0.8%   0.5%   1.3%
 de facto   2.0%   1.8%   4.9%
 never married   5.9%   4.9%   10.2%
Father’s marital status at interview 246   216   401  
 married   84.2%*   84.3%*   75.8%
 divorced   5.7%   5.6%   4.2%
 separated   3.7%   3.7%   5.7%
 widowed   0.8%   0.9%   0%
 de facto   1.2%   1.4%   3.7%
 never married   4.1%   3.7%   9.2%
 don’t know   0.4%   0.5%   1.3%
Mother hours in paid work (mean) 220 23.0 (SD: 20.0) 193 22.9 (SD: 19.9) 340 20.2 (SD: 19.1)
Father hours in paid work (mean) 216 43.0 (SD: 15.1) 190 43.3 (SD: 15.1) 312 41.5 (SD: 16.5)
Mother cigarettes/day 255   222   451  
 none   80.0%*   79.7%*   72.7%
 1-10/day   9.8%   9.9%   14.9%
 11-20/day   8.2%   8.6%   10.2%
 21-40/day   2.0%   1.8%   2.0%
 41+/day   0%   0%   0.2%
Father cigarettes/day 242   213   397  
 none   78.1%   79.3%*   71.5%
 1-10/day   7.9%   8.0%   10.8%
 11-20/day   10.3%   9.4%   10.8%
 21-40/day   2.9%   2.8%   6.3%
 41+/day   0.8%   0.5%   0.5%
Mother alcoholic drinks/wk mean (SD) 249 2.2 (SD: 3.8) 216 2.4 (SD: 4.0) 435 1.9 (SD: 3.0)
Father alcoholic drinks/wk mean (SD) 232 4.9 (SD: 6.6) 204 4.8 (SD: 6.6) 384 5.1 (SD: 7.9)
Pregnancy & Birth       
Mother’s age at child’s birth (mean, yrs) 256 30.2 (SD: 4.9)* 224 30.6 (SD: 4.8)* 449 29.3 (SD: 5.3)
Father’s age at child’s birth (mean, yrs) 243 33.0 (SD: 5.7)* 213 33.4 (SD: 5.7)* 398 32.0 (SD: 6.1)
Planned pregnancy 262 79.8% 229 81.2% 456 77.6%
 planned natural   73.7   75.6%   72.8%
 planned assisted   6.1%   5.7%   4.8%
 unplanned   20.2%   18.8%   22.4%
Child adopted 262 0% 229 0% 455 0.7%
Mother smoked during this pregnancy 256   223   448  
 Nil   84.0%*   83.9%*   74.6%
 Less than daily   5.9%   6.3%   10.0%
 1-10/day   6.3%   6.7%   9.4%
 11-20/day   3.5%   3.2%   4.7%
 21-40/day   0.4%   0%   1.3%
 41+/day   0%     0%
Father smoked during this pregnancy 235   207   385  
 Nil   77.0%*   78.3%*   68.8%
 Less than daily   3.0%   2.9%   4.9%
 1-10/day   5.1%   5.3%   9.6%
 11-20/day   11.1%   10.1%   11.4%
 21-40/day   3.4%   3.4%   4.9%
 41+/day   0.4%   0%   0.3%
Mother major illness during pregnancy 261 26.1% 228 25.0% 452 23.0%
Mother meds/supps during pregnancy       
 multivitamins 245 24.9% 215 25.1% 409 30.8%
 folate 246 61.4% 216 60.7% 409 64.8%
 calcium 246 10.2% 216 9.7% 409 14.9%
 iron 246 35.4% 216 35.6% 409 40.3%
 vitamin D 246 3.3%* 216 3.7% 409 7.8%
 fish oil 246 2.9% 216 2.8% 409 6.4%
 antibiotics 246 3.7% 216 3.7% 409 3.7%
 other 244 11.5%* 214 11.2% 409 6.4%
Mother any alcohol during pregnancy 255 18.1% 222 19.4%* 448 18.3%
Mother any coffee during pregnancy 253 56.1%* 220 57.7%* 448 54.7%
Child’s gestation (mean, weeks) 211 39.3 (SD: 1.8) 186 39.3 (SD: 1.8) 389 39.0 (SD: 2.3)
Child mode of delivery 90   71   210  
 normal vaginal   63.3%   63.4%   60.0%
 assisted vaginal   12.2%   12.7%   11.9%
 caesarian   23.3%   22.5%   27.1%
 other   1.1%   1.4%   1.0%
Child birthweight (mean, g) 225 3354.0 (SD: 613.8) 200 3357.2 (SD: 581.5) 344 3363.0 (SD: 676.9)
Child birthlength (mean, cm) 194 50.2 (SD: 3.4) 174 50.1 (SD: 3.4) 268 50.4 (SD: 3.7)
Child head circumference (mean, cm) 161 34.8 (SD: 3.0) 149 34.8 (SD: 3.1) 176 34.6 (SD: 3.1)
Child in multiple birth 253 3.6% 221 4.1% 448 3.1%
Child birth order (all live-born sibs) mean 262 1.90 (SD:1.02) 229 1.93 (SD: 1.05) 456 1.85 (SD: 1.03)
Early Life       
Child breastfeeding       
 any 260 85.8% 228 86.4% 454 81.3%
 if any, age started (wks) (mean, SD) 217 0.3 (SD 1.6) 191 0.3 (SD 1.7) 360 0.9 (SD 5.0)
 if any, weeks breastfed (mean, SD) 214 36.5 (SD 29.9) 188 36.5 (SD 30.4) 357 37.6 (SD 34.4)
Child formula feeding       
 age started (weeks) 194 18.2 (SD 19.9) 173 18.3 (SD 20.1) 348 16.4 (SD 16.5)
 weeks formula fed 239 35.1 (SD 34.3) 210 35.9 (35.2) 433 37.2 (SD 37.1)
Child cow’s milk commence age (weeks) 221 58.8 (SD 17.6) 193 57.9 (SD 17.6)* 405 61.6 (SD 22.4)
Child solids commence age (weeks) 234 24.2 (SD 16.1) 210 23.8 (SD 16.4) 424 23.9 (SD 9.6)
Mother smokes indoors near child 241   211   216  
 usually   0.8%   1.0%   1.4%
 sometimes   3.7%   3.8%   6.9%
 never   95.4%   95.3%   91.7%
Father smokes indoors near child 231   203   192  
 usually   1.3%   1.0%   2.6%
 sometimes   3.5%   3.5%   5.7%
 never   95.2%   95.6%   91.7%
  1. † Number of observations.
  2. * p < 0.05 vs controls by unadjusted logistic regression. See Table 2 for adjusted data.
  3. § SEIFA = Socio-Economic Indexes for Areas, a measure of residential positional disadvantage based on the Australian Bureau of Statistics Census of Population and Housing. The higher the score, the lower the disadvantage.