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Table 1 Baseline clinical and biochemical characteristics of the study sample (n = 502).

From: Hong Kong Chinese school children with elevated urine melamine levels: A prospective follow up study

  All participants Elevated urinary melamine level (urine melamine/creatinine ratio >7.1 ug/mmol)  
Characteristics (n = 502) No (n = 455) Yes (n = 47) p-value
Sex ψ     
   Male 167 (33.3%) 153 (33.6%) 14 (29.8%) 0.595 a
   Female 335 (66.7%) 302 (66.4%) 33 (70.2%)  
Age (years) 13.2 (3.0) 13.3 (3.0) 12.0 (2.8) 0.004 b
Body weight (kg) 43.6 (11.8) 44.1 (11.7) 39.3 (12.1) 0.008 b,*
Body height (cm) 152.3 (13.6) 152.8 (13.4) 147.4 (14.6) 0.010 b,*
BMI (kg/m2) 18.5 (3.0) 18.6 (3.0) 17.5 (2.4) 0.026 b,*
Weight status ψ     
   Normal 428 (85.3%) 384 (84.4%) 44 (93.6%) 0.193 c
   Overweight 51 (10.2%) 48 (10.5%) 3 (6.4%)  
   Obesity 23 (4.6%) 23 (5.1%) 0  
Urine albumin-creatinine ratio (mg/mmol) 0.70 (0.45 - 2.01) 0.69 (0.44 - 3.23) 0.70 (0.50 - 1.39) 0.820 d
Urine melamine/creatinine ratio (μg/mmol) , § 0.76 (0.00 - 2.62) 0.52 (0.00 - 1.73) 13.21 (9.09 - 21.55) <0.001 d
  1. Data marked with were presented as medians (interquartile ranges) and with ψ as frequencies (%), all others were presented as means (standard deviations).
  2. a Chi square test; b T-test; c Fisher's exact test; d non-parametric Mann-Whitney test.
  3. §Undetectable urine melamine level was set to zero.
  4. * There was no statistically significance between the two groups on body weight, body height, BMI and waist circumference after adjusting for age.