Pancreatic Steatosis and Its Relationship to β-Cell Dysfunction in Humans
Racial and Ethnic Variations
- Lidia S. Szczepaniak, PHD1⇓,
- Ronald G. Victor, MD1,
- Ruchi Mathur, MD1,
- Michael D. Nelson, PHD1,
- Edward W. Szczepaniak, PHD1,
- Nicole Tyer, MD1,
- Ida Chen, PHD1,
- Roger H. Unger, MD2,
- Richard N. Bergman, PHD1 and
- Ildiko Lingvay, MD2
- 1Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California
- 2Department of Internal medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Corresponding author: Lidia S. Szczepaniak, .
OBJECTIVE To evaluate racial/ethnic differences in pancreatic triglyceride (TG) levels and their relationship to β-cell dysfunction in humans.
RESEARCH DESIGN AND METHODS We studied black, Hispanic, and white adults who completed three research visits: screening and an oral glucose tolerance test; frequently sampled intravenous glucose tolerance tests for evaluation of β-cell function and insulin resistance; and proton magnetic resonance spectroscopy for evaluation of pancreatic and hepatic TG levels.
RESULTS Pancreatic TG levels were higher in Hispanics and whites than in blacks (P = 0.006). Hepatic TG levels were highest in Hispanics (P = 0.004). Compensatory insulin secretion and disposition index were higher in blacks (P = 0.003 and P = 0.024, respectively). Insulin sensitivity was comparable between Hispanics and blacks and was lower than in whites (P = 0.005). In blacks, compensatory insulin secretion increased steeply with small increments in pancreatic TG levels (R2 = 0.45, slope = 247). In whites, the range of pancreatic TG levels was higher, and the slope was less steep than in blacks (R2 = 0.27, slope = 27). In Hispanics, pancreatic TG levels were similar to those of whites, but compensatory insulin secretion was described by a combination of pancreatic and hepatic TG levels and visceral fat mass ( R2 = 0.32).
CONCLUSIONS In a multiethnic sample of adults with mild obesity and without diabetes, we found striking ethnic differences in the levels of pancreatic TGs and in the relationship between pancreatic TGs and β-cell dysfunction. Our data implicate pancreatic TG content measured by proton magnetic resonance spectroscopy as a noninvasive novel biomarker for pancreatic β-cell dysfunction, especially in the Hispanic population.
- Received April 12, 2012.
- Accepted May 31, 2012.
- © 2012 by the American Diabetes Association.
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