Association of insulin resistance with serum ferritin and aminotransferases-iron hypothesis

Table 5 Serum ferritin concentration and estimated insulin sensitivity indices by quintile of aspartate aminotransferase

	Quintile 1	Quintile 2	Quintile 3	Quintile 4	Quintile 5	P1	P2	P3
Serum ferritin concentration(mcg/L)
Non-Hispanic white males	148 (134, 162)	154 (140, 167)	180 (165, 196)	170 (155, 186)	228 (205, 251)	< 0.000001	< 0.000001	< 0.000001
Non-Hispanic white females	58 (51, 65)	61 (55, 68)	85 (76, 94)	102 (91, 112)	140 (122, 158)	0.0004	0.02	0.02
Non-Hispanic black males	175 (155, 196)	203 (178, 228)	197 (173, 222)	227 (203, 251)	267 (236, 298)	0.05	0.003	0.004
Non-Hispanic black females	84 (71, 96)	77 (66, 88)	80 (67, 92)	95 (81, 109)	127 (106, 149)	0.00001	0.004	0.005
Hispanic males	139 (124, 153)	134 (118, 151)	149 (134, 163)	155 (132, 177)	223 (194, 251)	< 0.000001	< 0.000001	< 0.000001
Hispanic females	47 (39, 56)	49 (42, 55)	59 (50, 68)	79 (57, 101)	101 (86, 115)	< 0.000001	0.00001	0.00002
Insulin sensitivity by the homeostasis model assessment (%S)4
Non-Hispanic white males	0.491 (0.457, 0.526)	0.517 (0.484, 0.550)	0.497 (0.466, 0.528)	0.506 (0.471, 0.541)	0.478 (0.441, 0.514)	NS	NS	NS
Non-Hispanic white females	0.575 (0.544, 0.607)	0.597 (0.559, 0.630)	0.591 (0.554, 0.628)	0.555 (0.521, 0.588)	0.506 (0.470, 0.543)	0.02	NS	NS
Non-Hispanic black males	0.512 (0.465, 0.559)	0.531 (0.479, 0.584)	0.528 (0.486, 0.569)	0.557 (0.508, 0.605)	0.561 (0.499, 0.623)	NS	NS	NS
Non-Hispanic black females	0.447 (0.410, 0.484)	0.452 (0.418, 0.487)	0.472 (0.437, 0.506)	0.461 (0.424, 0.499)	0.443 (0.401, 0.485)	NS	NS	NS
Hispanic males	0.501 (0.460, 0.542)	0.55 (0.495, 0.604)	0.524 (0.473, 0.574)	0.477 (0.424, 0.530)	0.404 (0.359, 0.449)	< 0.000001	< 0.000001	< 0.000001
Hispanic females	0.472 (0.430, 0.514)	0.48 (0.443, 0.516)	0.468 (0.430, 0.507)	0.49 (0.442, 0.539)	0.374 (0.330, 0.418)	0.006	NS	NS
Insulin sensitivity by the simple QUICKI5
Non-Hispanic white males	0.337 (0.333, 0.340)	0.34 (0.337, 0.343)	0.338 (0.335, 0.341)	0.338 (0.334, 0.342)	0.334 (0.330, 0.338)	NS	NS	NS
Non-Hispanic white females	0.346 (0.343, 0.349)	0.347 (0.344, 0.350)	0.347 (0.343, 0.350)	0.343 (0.340, 0.346)	0.336 (0.332, 0.340)	0.009	NS	NS
Non-Hispanic black males	0.337 (0.332, 0.342)	0.339 (0.334, 0.344)	0.341 (0.337, 0.345)	0.343 (0.338, 0.348)	0.3417 (0.336, 0.346)	NS	NS	NS
Non-Hispanic black females	0.331 (0.327, 0.335)	0.332 (0.328, 0.336)	0.335 (0.332, 0.339)	0.333 (0.329, 0.337)	0.33 (0.326, 0.334)	NS	NS	NS
Hispanic males	0.337 (0.333, 0.342)	0.342 (0.337, 0.346)	0.338 (0.333, 0.343)	0.333 (0.328, 0.338)	0.325 (0.320, 0.329)	< 0.000001	< 0.000001	< 0.000001
Hispanic females	0.334 (0.329, 0.338)	0.336 (0.332, 0.340)	0.334 (0.330, 0.338)	0.335 (0.331, 0.340)	0.32 (0.315, 0.325)	0.0001	NS	NS

Data presented mean with 95%CI.

¹P values for trend, unadjusted;

²P values for trend, after adjustment for age and body mass index;

³P values for trend, after adjustment for age, body mass index, alcohol consumption, and mineral/iron supplement;

⁴%S = 22.5/(fasting insulin concentration in mU/L ×fasting glucose concentration in mmol/L);

⁵Quicki = 1/[log(fasting glucose concentration in mg/dL) + log(fasting insulin concentration in mU/L). NS: Not significant; QUICKI: Quantitative insulin sensitivity check index.