Table 1.

Empirical evidence of race differences in glucose metabolism and metabolic inflexibility in adults.

Reference	Sample	Method	Results: African Americans Relative to Whites
			Fasting or 2-h post-load glucose or insulin	Insulin Sensitivity	β-cell function
42	60 women Premenopausal	IVGT		↓ IS	↑ AIR
12	13,287 Nondiabetic	Fasting insulin	> fasting insulin (women) = fasting insulin (men)
64	74	Hyperglycemic clamp	< first and second-phase insulin response	↓ IS	↑ β-cell function ↑ glucose clearance
65	34 obese	Insulin-modified FSIVGT	= fasting insulin = fasting glucose	↓ IS	↑ AIR ↑ glucose disposal
10	366	2-h OGTT	> 2-h post-load insulin
66	723 Nondiabetic	2-h OGTT; insulin-modified FSIVGT	> fasting insulin > 2-h post-load insulin = fasting glucose = 2-h post-load glucose	↓ IS	↑ AIR = glucose effectiveness
67	272 Nondiabetics; first-degree relatives of individuals with T2D	2-h OGTT			↑ AIR (NGT only) ↑ β-cell function (NGT only)
68	62 Healthy	2-h OGTT; tolbutamide-modified, FSIVGT	< glucose peak response = glucose = C-peptide levels	↓ IS index ↓ basal and postprandial hepatic insulin extraction ↓ post-prandial insulin	↑ basal insulin
69	333 Obese nondiabetic	2-h OGTT FSIVGT	= fasting insulin = 2-h post-load insulin < 2-h post-load glucose	↓ IS	↑ AIR ↑ glucose disposal
70	2105 women Nondiabetic	HOMA		↓ HOMA % IS	↑ HOMA % β-cell function

Note. ↓ indicates variable is lower (↑higher, = equivalent) in African Americans compared to Whites. AIR is acute insulin response to intravenous glucose, FSIVGT is frequently sampled intravenous glucose tolerance test, HOMA is homeostatic model assessment, IS is insulin sensitivity, IVGT is intravenous glucose tolerance test, NGT is normal glucose tolerance, OGTT is oral glucose tolerance test, T2D is type 2 diabetes. Table is partially adapted from Golden et al., 2012.⁷¹