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

Table 7 Serum ferritin concentration and estimated insulin sensitivity indices by quintile of alanine aminotransferase

	Quintile 1	Quintile 2	Quintile 3	Quintile 4	Quintile 5	P1	P2	P3
Serum ferritin concentration (mcg/L)
Non-Hispanic white males	147 (132, 162)	169 (153, 185)	168 (152, 183)	177 (159, 194)	220 (200, 241)	< 0.000001	< 0.000001	< 0.000001
Non-Hispanic white females	71 (63, 79)	71 (61, 82)	86 (77, 95)	95 (84, 107)	123 (107, 139)	0.05	0.02	0.02
Non-Hispanic black males	168 (147, 189)	187 (165, 210)	201 (177, 225)	247 (219, 275)	267 (238, 296)	0.01	0.00005	0.00005
Non-Hispanic black females	80 (67, 92)	79 (68, 89)	87 (73, 100)	98 (81, 114)	120 (100, 140)	0.00003	0.000004	0.000005
Hispanic males	128 (113, 143)	128 (116, 140)	142 (126, 157)	172 (144, 200)	229 (206, 253)	< 0.000001	< 0.000001	< 0.000001
Hispanic females	42 (35, 49)	70 (48, 93)	57 (49, 65)	64 (55, 73)	101 (87, 116)	< 0.000001	0.000009	0.000009
Insulin sensitivity by the homeostasis model assessment (%S)4
Non-Hispanic white males	0.551 (0.517, 0.584)	0.544 (0.511, 0.578)	0.512 (0.476, 0.549)	0.483 (0.448, 0.518)	0.399 (0.370, 0.429)	< 0.000001	< 0.000001	< 0.000001
Non-Hispanic white females	0.634 (0.602, 0.666)	0.628 (0.591, 0.664)	0.583 (0.546, 0.622)	0.55 (0.519, 0.582)	0.429 (0.395, 0.463)	0.00002	0.004	0.002
Non-Hispanic black males	0.63 (0.576, 0.684)	0.576 (0.522, 0.630)	0.564 (0.514, 0.615)	0.478 (0.423, 0.524)	0.44 (0.397, 0.482)	0.00002	0.003	0.003
Non-Hispanic black females	0.527 (0.490, 0.563)	0.498 (0.462, 0.534)	0.462 (0.424, 0.500)	0.427 (0.389, 0.465)	0.363 (0.330, 0.396)	< 0.000001	< 0.000001	< 0.000001
Hispanic males	0.635 (0.569, 0.700)	0.57 (0.525, 0.615)	0.48 (0.430, 0.530)	0.448 (0.410, 0.486)	0.324 (0.295, 0.352)	< 0.000001	< 0.000001	< 0.000001
Hispanic females	0.55 (0.509, 0.591)	0.528 (0.484, 0.571)	0.468 (0.427, 0.509)	0.409 (0.365, 0.452)	0.331 (0.295, 0.368)	< 0.000001	0.000003	0.000002
Insulin sensitivity by the simple QUICKI5
Non-Hispanic white males	0.344 (0.341, 0.347)	0.343 (0.339, 0.346)	0.339 (0.335, 0.342)	0.335 (0.332, 0.339)	0.326 (0.322, 0.329)	< 0.000001	< 0.000001	< 0.000001
Non-Hispanic white females	0.352 (0.349, 0.355)	0.35 (0.347, 0.345)	0.346 (0.342, 0.349)	0.343 (0.340, 0.346)	0.327 (0.324, 0.331)	0.000001	0.0005	0.0002
Non-Hispanic black males	0.349 (0.344, 0.354)	0.344 (0.339, 0.349)	0.343 (0.338, 0.348)	0.335 (0.330, 0.339)	0.33 (0.326, 0.335)	0.00005	0.01	0.009
Non-Hispanic black females	0.341 (0.337, 0.345)	0.338 (0.334, 0.342)	0.333 (0.329, 0.337)	0.33 (0.326, 0.334)	0.321 (0.316, 0.325)	< 0.000001	< 0.000001	< 0.000001
Hispanic males	0.348 (0.343, 0.353)	0.345 (0.341, 0.349)	0.333 (0.328, 0.338)	0.332 (0.328, 0.336)	0.317 (0.313, 0.321)	< 0.000001	< 0.000001	< 0.000001
Hispanic females	0.343 (0.339, 0.347)	0.34 (0.336, 0.344)	0.334 (0.330, 0.338)	0.327 (0.323, 0.331)	0.315 (0.311, 0.320)	< 0.000001	< 0.000001	< 0.000001

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.