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Table 3 Impact of corticosteroid use, disease activity and covariates on height Z-scores and BMI Z-scores

From: Growth and weight gain in children with juvenile idiopathic arthritis: results from the ReACCh-Out cohort

  Impact on height Z-scores Impact on BMI Z-scores
Variable Unadjusteda
(95% CI)
p value Adjusted
(95% CI)
p value Unadjusted
(95% CI)
p value Adjusted
(95% CI)
p value
Cumulative corticosteroidsb −0.69 (−0.82, −0.56) <0.01 −0.64 (−0.77, −0.50) <0.01 0.79 (0.63, 0.96) <0.01 0.74 (0.56, 0.92) <0.01
Cumulative disease activityc −0.02 (−0.03, −0.01) <0.01 −0.01 (−0.02, 0.00) 0.04 0.00 (−0.01, 0.01) 0.49 −0.01 (−0.02, 0.00) 0.17
Parental educationd
 Less than high school Reference   Reference   Reference   Reference  
 High school/secondary 0.29 (−0.18, 0.77) 0.23 0.31 (−0.18, 0.80) 0.21 0.005 (−0.50, 0.51) 0.98 0.09 (−0.43, 0.61) 0.73
 Some post-secondary 0.34 (−0.12, 0.80) 0.15 0.39 (−.08, 0.87) 0.11 −0.01 (−0.50, 0.48) 0.96 0.09 (−0.41, 0.60) 0.72
 University degree 0.32 (−0.14, 0.78) 0.18 0.36 (−0.11, 0.84) 0.14 −0.17 (−0.66, 0.31) 0.49 −0.08 (−0.58, 0.43) 0.77
 Postgraduate degree 0.40 (−0.08, 0.89) 0.10 0.43 (−0.07, 0.93) 0.09 −0.25 (−0.76, 0.26) 0.33 −0.11 (−0.64, 0.42) 0.68
Primary Ethnicitye
 British Reference   Reference   Reference   Reference  
 French −0.09 (−0.26, 0.09) 0.32 −0.11 (−0.29, 0.07) 0.24 −0.36 (−0.55, −0.17) <0.01 −0.33 (−0.52, −0.13) <0.01
 Indigenous Canadian 0.15 (−0.15, 0.45) 0.34 0.15 (−0.16, 0.46) 0.33 −0.05 (−0.37, 0.27) 0.76 −0.03 (−0.36, 0.30) 0.84
 Other European 0.03 (−0.14, 0.19) 0.74 0.03 (−0.14, 0.20) 0.75 −0.31 (−0.49, −0.13) <0.01 −0.23 (−0.41, −0.05) 0.01
 South Asian 0.33 (0.0, 0.66) 0.05 0.34 (0.0, 0.67) 0.05 −0.13 (−0.48, 0.22) 0.47 −0.13 (−0.49, 0.23) 0.48
 Other −0.07 (−0.27, 0.13) 0.47 −0.03 (−0.24, 0.18) 0.75 −0.23 (−0.44, −0.02) 0.03 −0.13 (−0.35, 0.09) 0.25
JIA categories
 Oligoarthritis Reference   Reference   Reference   Reference  
 RF-neg polyarthritis −0.17 (−0.34, −0.01) 0.04 −0.14 (−0.32, 0.03) 0.10 −0.01 (−0.18, 0.17) 0.96 0.00 (−0.18, 0.19) 0.99
 Enthesitis-related 0.17 (−0.01, 0.36) 0.07 0.21 (0.01, 0.40) 0.04 0.08 (−0.12, 0.27) 0.45 −0.04 (−0.25, 0.18) 0.74
 Systemic −0.36 (−0.61, −0.10) 0.01 −0.23 (−0.51, 0.05) 0.10 0.68 (0.41, 0.95) <0.01 0.44 (0.15, 0.74) <0.01
 Psoriatic 0.04 (−0.23, 0.30) 0.79 0.16 (−0.12, 0.44) 0.26 0.41 (0.13, 0.69) <0.01 0.31 (0.01, 0.61) 0.05
 RF-pos polyarthritis −0.13 (−0.46, 0.19) 0.43 −0.03 (−0.36, 0.31) 0.88 −0.13 (−0.47, 0.21) 0.46 −0.25 (−0.60, 0.10) 0.17
 Undifferentiated −0.18 (−0.39, 0.04) 0.11 −0.11 (−0.33, 0.12) 0.37 0.03 (−0.20, 0.25) 0.82 0.02 (−0.22, 0.26) 0.86
  1. aUnadjusted Beta coefficients and (95% CI) were obtained from mixed effect models including only one independent variable at a time. Adjusted beta coefficients are from a mixed effects model where cumulative corticosteroids in previous 6 months, cumulative disease activity in previous 6 months, parental education, ethnicity and JIA category were entered together. Cumulative prednisone and disease activity were time-variant variables. All mixed effects models were run by subject and included random intercept, random slope and a quadratic term for time since diagnosis in weeks. They can be represented by: dependent variable = b1*constant + b2*time + b3*time square + b4* first independent variable + b5* second independent variable
  2. bCumulative corticosteroids were calculated as area under the curve of daily prednisone equivalents per kilogram of body weight recorded at each clinic visit, using the trapezoid method; a one unit change corresponds to an increase of 1 mg/Kg of prednisone equivalents per day sustained for 6 months. For the first study visit, corticosteroids were assumed to start at diagnosis
  3. cCumulative disease activity was calculated as area under the curve of the physician global assessment of disease activity recorded at each clinic visit, using the trapezoid method; a one unit change corresponds to an increase of 1 cm in the physician global assessment sustained for 6 months. For the first study visit the physician global assessment was assumed to be zero the day before disease onset
  4. dThe level of education of the parent who had a higher level of education
  5. eThe ethnic group listed first; up to six ethnic groups could be listed for each child as defined by Statistics Canada