Table 1.

Clinical characteristics of the subjects.

	Ziyang (n = 2797)*	Ningshan (n = 2889)*
	Median [IQR]	Median [IQR]
Glucose (mmol/l)	5.19 [4.49–6.07]	4.00 [3.02–5.53]
Insulin (mIU/l)	10.0 [7.0–20.5]	9.4 [7.0–15.9]
Selenium (μg/l)	103 [79–134]	58 [40–82]
BMI (kg/m2)	22.3 [20.5–24.4]	23.0 [21.0–25.4]
Age (y)	50 [39–59]	47 [39–56]
Gender (%m)	30.7%	32.2%