Table 2.

Association between urine melamine level and daily milk consumption.

	Drinking more than a cup of milk per day #
	No (n = 378)	Yes (n = 99)	p-value
Urine melamine (μg/l) §	6.0 (0 - 25.0)	11.0 (0 - 33.0)	0.280 a
Urine melamine/creatinine ratio (μg/mmol)	0.62 (0 - 2.33)	1.00 (0 - 3.19)	0.182 a
Elevated urine melamine level (melamine/creatinine ratio >7.1 μg/mmol) ψ
No	347 (91.8%)	85 (85.9%)	0.072 b
Yes	31 (8.2%)	14 (14.1%)

Data marked ^ψ are presented as frequencies (percentages), all others are medians (interquartile ranges).

^# There were 25 subjects with missing milk consumption data.

^§ Undetectable urine melamine level was set to zero.

^a Mann-Whitney test; ^b Pearson Chi square test.