Hemoglobin within normal range is negatively related to hemoglobin A1c in a nondiabetic American population aged 16 years and older

Table 2 Relation between hemoglobin (1 g/dL) and hemoglobin A1c level (%)

	Unadjusted model β (95%CI)	Minimally adjusted model β (95%CI)	Fully adjusted model β (95%CI)
Hemoglobin	-0.01 (-0.01, -0.01)c	-0.01 (-0.01, -0.00)c	-0.08 (-0.08, -0.07)c
Hemoglobin (Quartile)
Q1	Reference	Reference	Reference
Q2	0.01 (0.00, 0.02)	0.01 (-0.00, 0.01)	-0.06 (-0.07, -0.05)c
Q3	0.02 (0.01, 0.03)b	0.01 (-0.00, 0.02)	-0.12 (-0.13, -0.11)c
Q4	-0.04 (-0.05, -0.03)c	-0.02 (-0.03, -0.01)c	-0.23 (-0.24, -0.22)c
P for trend	< 0.001	< 0.001	< 0.001

^aP< 0.01.

^bP< 0.001.

^cP< 0.0001.

Three models were employed to analyze the relation in this work, namely, unadjusted model, minimally adjusted model, and fully adjusted model. No covariates were regulated in unadjusted model. Only age and gender were regulated in minimally adjusted model. Lastly, in fully adjusted model, all parameters were adjusted, including age, gender, ethnicity, educational level, marital status, smoking behavior, body mass index, uric acid, total protein, serum creatinine, blood glucose, alanine aminotransferase, cholesterol, platelet count, and red/ white blood cell count.