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Thomas A Buchanan, MD
Professor of Medicine
Vice Dean For Research
Director of The CTSI,
Co Director, Diabetes and Obesity Research Institute
Endocrine Division Chief in The Department of Medicine
CSC 205 Health Sciences Campus Los Angeles
+1 323 442 1803


Thomas A. Buchanan, M.D., is Professor of Medicine, Obstetrics and Gynecology, and Physiology and Biophysics; Vice Dean for Research; Chief of the Division of Endocrinology and Diabetes in the Department of Medicine in Keck School of Medicine at the University of Southern California (USC) in Los Angeles. He is also the founding director of the Southern California Clinical and Translational Science Institute.

Scientifically, Dr. Buchanan conducts research into the etiology, pathogenesis, genetics and prevention of gestational and type 2 diabetes with a focus on diabetes in Hispanic Americans. Buchanan and colleagues have conducted longitudinal studies of high risk individuals to define patterns of change in insulin resistance and insulin secretion that lead to type 2 diabetes. Based on their findings, they then conducted the first successful type 2 diabetes prevention study in the United States. The biological information gained from that study pointed to a specific pancreatic beta cell defect that is heritable, a finding that formed the basis for a large family based study that has helped to identify the genetic basis for the metabolic abnormalities that lead to type 2 diabetes. In aggregate studies performed by Buchanan and his colleagues have contributed to important advances in clinical care for gestational diabetes and the prevention of type 2 diabetes in Hispanic Americans

Administratively, Dr. Buchanan has championed the development of clinical and translational research at USC, first through his role as director of the General Clinical Research Center (1996-2010). In 2010, he led the team that created the Southern California Clinical and Translational Science Institute, which in turn won a prestigious $56.8 million Clinical and Translational Science Award from the National Institutes of Health (NIH) to support and promote scientific discoveries and their application in real-life settings to health and health care. He built and directed one of the nation’s largest General Clinical Research Center (GCRC) programs. Since 2010, he has been director and principal investigator of USC’s new Southern California Clinical and Translational Science Institute (SC CTSI).

During his career, Dr. Buchanan has brought more than $180 million in extramural research funding to USC and the Keck School. He has been ranked as highly 1st at USC and 50th world-wide in annual NIH funding.

Dr. Buchanan received his medical degree from the University of Iowa, Iowa City, where he completed residency training in internal medicine. He completed his fellowship training in endocrinology and metabolism at Northwestern University Medical School, Chicago, Illinois.

A native of Iowa, Dr. Buchanan is an avid cyclist on the challenging Angeles Crest Highway near Los Angeles, a downhill skier and a dedicated family man.


Western Society for Clinical Investigation: Mayo Soley Award, 2014

University of California, Los Angeles: Josiah Brown Award, 2014

Irish Endocrine Society: Lilly Lecture, 2011

Association of American Physicians: Elected Member, 2006

American Diabetes Association: Distinguished Clinical Scientist Award, 2004

J Clin Endocrinol Metab: Endocrine Society-Pharmacia Award for Excellence in Published Clinical Research, 2002

University of Washington: John Ensinck Lecture, 2000

American Diabetes Association: Norbert Freinkel Award, 1999

American Diabetes Association: Chair, Council on Diabetes and Pregnancy, 1995-1997

NIH: Chair, Special Emphasis Panel, Hyperglycemia and Pregnancy Outcomes , 1995-1997

Canadian Diabetes Association: Novo-Nordisk International Lecture, 1995

Australian Diabetes Association: Medisense International Lecture, 1995

American Diabetes Association, Northern Illinois Affliate: Young Investigator Award, 1983

University of Iowa: Alpha Omega Alpha, 1978

Iowa State University: Phi Beta Kappa, 1974


The Association of Estrogen Receptor-ß Gene Variation with Salt Sensitive Blood Pressure. J Clin Endocrinol Metab. 2017 Sep 05. View in: PubMed

A Genome-Wide Association Study of IVGTT-Based Measures of First-Phase Insulin Secretion Refines the Underlying Physiology of Type 2 Diabetes Variants. Diabetes. 2017 Aug; 66(8):2296-2309. View in: PubMed

Review of methods for measuring ß-cell function: Design considerations from the Restoring Insulin Secretion (RISE) Consortium. Diabetes Obes Metab. 2017 May 11. View in: PubMed

Pioglitazone is equally effective for diabetes prevention in older versus younger adults with impaired glucose tolerance. Age (Dordr). 2016 Dec; 38(5-6):485-493. View in: PubMed

Improved Performance of Dynamic Measures of Insulin Response Over Surrogate Indices to Identify Genetic Contributors of Type 2 Diabetes: The GUARDIAN Consortium. Diabetes. 2016 Jul; 65(7):2072-80. View in: PubMed

Diabetes Incidence and Glucose Tolerance after Termination of Pioglitazone Therapy: Results from ACT NOW. J Clin Endocrinol Metab. 2016 May; 101(5):2056-62. View in: PubMed

Ambient Air Pollutants Have Adverse Effects on Insulin and Glucose Homeostasis in Mexican Americans. Diabetes Care. 2016 Apr; 39(4):547-54. View in: PubMed

Genetic Variants Associated With Quantitative Glucose Homeostasis Traits Translate to Type 2 Diabetes in Mexican Americans: The GUARDIAN (Genetics Underlying Diabetes in Hispanics) Consortium. Diabetes. 2015 May; 64(5):1853-66. View in: PubMed

A novel insulin resistance index to monitor changes in insulin sensitivity and glucose tolerance: the ACT NOW study. J Clin Endocrinol Metab. 2015 May; 100(5):1855-62. View in: PubMed

Association of maternal diabetes with autism in offspring. JAMA. 2015 Apr 14; 313(14):1425-34. View in: PubMed

Variation in PPARG is associated with longitudinal change in insulin resistance in Mexican Americans at risk for type 2 diabetes. J Clin Endocrinol Metab. 2015 Mar; 100(3):1187-95. View in: PubMed

Racial and ethnic disparities in extremes of fetal growth after gestational diabetes mellitus. Diabetologia. 2015 Feb; 58(2):272-81. View in: PubMed

High calorie intake is associated with worsening insulin resistance and ß-cell function in Hispanic women after gestational diabetes mellitus. Diabetes Care. 2014 Dec; 37(12):3294-300. View in: PubMed

Genetic variation in MTNR1B is associated with gestational diabetes mellitus and contributes only to the absolute level of beta cell compensation in Mexican Americans. Diabetologia. 2014 Jul; 57(7):1391-9. View in: PubMed

Baseline adiponectin levels do not influence the response to pioglitazone in ACT NOW. Diabetes Care. 2014 Jun; 37(6):1706-11. View in: PubMed

Randomized controlled trial to evaluate the effects of combined progressive exercise on metabolic syndrome in breast cancer survivors: rationale, design, and methods. BMC Cancer. 2014 Apr 03; 14:238. View in: PubMed

Insulin sensitivity and insulin clearance are heritable and have strong genetic correlation in Mexican Americans. Obesity (Silver Spring). 2014 Apr; 22(4):1157-64. View in: PubMed

Gestational diabetes mellitus, maternal obesity, and adiposity in offspring. J Pediatr. 2014 Apr; 164(4):807-10. View in: PubMed

Longitudinal changes in insulin sensitivity and beta cell function between women with and without a history of gestational diabetes mellitus. Diabetologia. 2013 Dec; 56(12):2753-60. View in: PubMed

Prevention of diabetes with pioglitazone in ACT NOW: physiologic correlates. Diabetes. 2013 Nov; 62(11):3920-6. View in: PubMed

Prediction of diabetes based on baseline metabolic characteristics in individuals at high risk. Diabetes Care. 2013 Nov; 36(11):3607-12. View in: PubMed

High-fat diet is associated with obesity-mediated insulin resistance and ß-cell dysfunction in Mexican Americans. J Nutr. 2013 Apr; 143(4):479-85. View in: PubMed

Self-reported physical activity is associated with ß-cell function in Mexican American adults. Diabetes Care. 2013 Mar; 36(3):638-44. View in: PubMed

Pioglitazone slows progression of atherosclerosis in prediabetes independent of changes in cardiovascular risk factors. Arterioscler Thromb Vasc Biol. 2013 Feb; 33(2):393-9. View in: PubMed

The diagnosis of gestational diabetes mellitus: new paradigms or status quo? J Matern Fetal Neonatal Med. The diagnosis of gestational diabetes mellitus: new paradigms or status quo? J Matern Fetal Neonatal Med. 2012 Dec; 25(12):2564-9. View in: PubMed

Gestational diabetes mellitus: risks and management during and after pregnancy. Nat Rev Endocrinol. 2012 Nov; 8(11):639-49. View in: PubMed

Metabolic syndrome is linked to chromosome 7q21 and associated with genetic variants in CD36 and GNAT3 in Mexican Americans. Obesity (Silver Spring). 2012 Oct; 20(10):2083-92. View in: PubMed

Lysine-specific demethylase 1: an epigenetic regulator of salt-sensitive hypertension. Am J Hypertens. 2012 Jul; 25(7):812-7. View in: PubMed

Deterioration in cardiometabolic risk markers in obese women during depot medroxyprogesterone acetate use. Contraception. 2012 Jan; 85(1):36-41. View in: PubMed

Novel loci for adiponectin levels and their influence on type 2 diabetes and metabolic traits: a multi-ethnic meta-analysis of 45,891 individuals. PLoS Genet. 2012; 8(3):e1002607. View in: PubMed

A genome-wide association search for type 2 diabetes genes in African Americans. PLoS One. 2012; 7(1):e29202. View in: PubMed

Approach to the patient with gestational diabetes after delivery. J Clin Endocrinol Metab. 2011 Dec; 96(12):3592-8. View in: PubMed

Variants of the caveolin-1 gene: a translational investigation linking insulin resistance and hypertension. J Clin Endocrinol Metab. 2011 Aug; 96(8):E1288-92. View in: PubMed

The vicious cycle of maternal diabetes and obesity: moving from "what" to "how" and "why". J Pediatr. 2011 Jun; 158(6):872-3. View in: PubMed

A better index of body adiposity. Obesity (Silver Spring). 2011 May; 19(5):1083-9. View in: PubMed

Pioglitazone for diabetes prevention in impaired glucose tolerance. N Engl J Med. 2011 Mar 24; 364(12):1104-15. View in: PubMed

Meta-analysis identifies 13 new loci associated with waist-hip ratio and reveals sexual dimorphism in the genetic basis of fat distribution. Nat Genet. 2010 Nov; 42(11):949-60. View in: PubMed

Association analyses of 249,796 individuals reveal 18 new loci associated with body mass index. Nat Genet. 2010 Nov; 42(11):937-48. View in: PubMed

Limitations in surrogate measures of insulin resistance. J Clin Endocrinol Metab. 2010 Nov; 95(11):4874-6. View in: PubMed

Detailed physiological characterization of the development of type 2 diabetes in Hispanic women with prior gestational diabetes mellitus. Diabetes. 2010 Oct; 59(10):2625-30. View in: PubMed

Preventing type 2 diabetes with low-dose combinations. Lancet. 2010 Jul 10; 376(9735):72-4. View in: PubMed

Stemming the tide of type 2 diabetes: bring on the "big guns". Obesity (Silver Spring). 2010 Jun; 18(6):1065-7. View in: PubMed

Detailed physiologic characterization reveals diverse mechanisms for novel genetic Loci regulating glucose and insulin metabolism in humans. Diabetes. 2010 May; 59(5):1266-75. View in: PubMed

Diabetes: preventing type 2 diabetes mellitus: is metformin the answer? Nat Rev Endocrinol. Diabetes: preventing type 2 diabetes mellitus: is metformin the answer? Nat Rev Endocrinol. 2010 May; 6(5):253-4. View in: PubMed

Obese adolescents show impaired meal responses of the appetite-regulating hormones ghrelin and PYY. Obesity (Silver Spring). 2010 May; 18(5):918-25. View in: PubMed

International association of diabetes and pregnancy study groups recommendations on the diagnosis and classification of hyperglycemia in pregnancy. Diabetes Care. 2010 Mar; 33(3):676-82. View in: PubMed

Declining beta-cell compensation for insulin resistance in Hispanic women with recent gestational diabetes mellitus: association with changes in weight, adiponectin, and C-reactive protein. Diabetes Care. 2010 Feb; 33(2):396-401. View in: PubMed

Genetic variation in GIPR influences the glucose and insulin responses to an oral glucose challenge. Nat Genet. 2010 Feb; 42(2):142-8. View in: PubMed

Additive effects of genetic variation in GCK and G6PC2 on insulin secretion and fasting glucose. Diabetes. 2009 Dec; 58(12):2946-53. View in: PubMed

Evidence for sex-specific associations between variation in acid phosphatase locus 1 (ACP1) and insulin sensitivity in Mexican-Americans. J Clin Endocrinol Metab. 2009 Oct; 94(10):4094-102. View in: PubMed

Replication of calpain-10 genetic association with carotid intima-media thickness. Atherosclerosis. 2009 Aug; 205(2):503-5. View in: PubMed

Actos Now for the prevention of diabetes (ACT NOW) study. BMC Endocr Disord. 2009 Jul 29; 9:17. View in: PubMed

Variation in IGF2BP2 interacts with adiposity to alter insulin sensitivity in Mexican Americans. Obesity (Silver Spring). 2009 Apr; 17(4):729-36. View in: PubMed

Variants in MTNR1B influence fasting glucose levels. Nat Genet. 2009 Jan; 41(1):77-81. View in: PubMed

Effect of pioglitazone on progression of subclinical atherosclerosis in non-diabetic premenopausal Hispanic women with prior gestational diabetes. Atherosclerosis. 2008 Jul; 199(1):207-14. View in: PubMed

Variations in the G6PC2/ABCB11 genomic region are associated with fasting glucose levels. J Clin Invest. 2008 Jul; 118(7):2620-8. View in: PubMed

Carotid intima-media thickness (cIMT) cosegregates with blood pressure and renal function in hypertensive Hispanic families. Atherosclerosis. 2008 May; 198(1):160-5. View in: PubMed

Association of insulin sensitivity and glucose tolerance with the c. 825C>T variant of the G protein beta-3 subunit gene. J Diabetes Complications. 2008 May-Jun; 22(3):205-9. View in: PubMed

Evidence of interaction between PPARG2 and HNF4A contributing to variation in insulin sensitivity in Mexican Americans. Diabetes. 2008 Apr; 57(4):1048-56. View in: PubMed

A longitudinal study of lipids and blood pressure in relation to method of contraception in Latino women with prior gestational diabetes mellitus. Diabetes Care. 2007 Aug; 30(8):1952-8. View in: PubMed

Genetics of gestational diabetes mellitus and type 2 diabetes. Diabetes Care. 2007 Jul; 30 Suppl 2:S134-40. View in: PubMed

Summary and recommendations of the Fifth International Workshop-Conference on Gestational Diabetes Mellitus. Diabetes Care. 2007 Jul; 30 Suppl 2:S251-60. View in: PubMed

What is gestational diabetes? Diabetes Care. What is gestational diabetes? Diabetes Care. 2007 Jul; 30 Suppl 2:S105-11. View in: PubMed

A genome-wide association study of type 2 diabetes in Finns detects multiple susceptibility variants. Science. 2007 Jun 01; 316(5829):1341-5. View in: PubMed

(How) can we prevent type 2 diabetes? Diabetes. (How) can we prevent type 2 diabetes? Diabetes. 2007 Jun; 56(6):1502-7. View in: PubMed

Transcription factor 7-like 2 (TCF7L2) is associated with gestational diabetes mellitus and interacts with adiposity to alter insulin secretion in Mexican Americans. Diabetes. 2007 May; 56(5):1481-5. View in: PubMed

Effect of antihypertensive therapy on progression of carotid intima-media thickness in patients with type 2 diabetes mellitus. Am J Cardiol. 2007 Apr 01; 99(7):956-60. View in: PubMed

Screening of 134 single nucleotide polymorphisms (SNPs) previously associated with type 2 diabetes replicates association with 12 SNPs in nine genes. Diabetes. 2007 Jan; 56(1):256-64. View in: PubMed

Subsets of Finns with high HDL to total cholesterol ratio show evidence for linkage to type 2 diabetes on chromosome 6q. Hum Hered. 2007; 63(1):17-25. View in: PubMed

Common variants in maturity-onset diabetes of the young genes contribute to risk of type 2 diabetes in Finns. Diabetes. 2006 Sep; 55(9):2534-40. View in: PubMed

Effect of peroxisome proliferator-activated receptor gamma agonist treatment on subclinical atherosclerosis in patients with insulin-requiring type 2 diabetes. Diabetes Care. 2006 Jul; 29(7):1545-53. View in: PubMed

Effects of transdermal testosterone administration on insulin sensitivity, fat mass and distribution, and markers of inflammation and thrombolysis in human immunodeficiency virus-infected women with mild to moderate weight loss. Fertil Steril. 2006 Jun; 85(6):1794-802. View in: PubMed

Coordinate changes in plasma glucose and pancreatic beta-cell function in Latino women at high risk for type 2 diabetes. Diabetes. 2006 Apr; 55(4):1074-9. View in: PubMed

Long-acting injectable progestin contraception and risk of type 2 diabetes in Latino women with prior gestational diabetes mellitus. Diabetes Care. 2006 Mar; 29(3):613-7. View in: PubMed

Effect of pioglitazone on pancreatic beta-cell function and diabetes risk in Hispanic women with prior gestational diabetes. Diabetes. 2006 Feb; 55(2):517-22. View in: PubMed

Mitochondrial polymorphisms and susceptibility to type 2 diabetes-related traits in Finns. Hum Genet. 2005 Nov; 118(2):245-54. View in: PubMed

Sequence variation in PPARG may underlie differential response to troglitazone. Diabetes. 2005 Nov; 54(11):3319-25. View in: PubMed

Insulin resistance and preeclampsia in gestational diabetes mellitus. Diabetes Care. 2005 Aug; 28(8):1995-2000. View in: PubMed

Use of medications to prevent type 2 diabetes. Curr Diab Rep. 2005 Aug; 5(4):237-9. View in: PubMed

Effect of thiazolidinedione treatment on progression of subclinical atherosclerosis in premenopausal women at high risk for type 2 diabetes. J Clin Endocrinol Metab. 2005 Apr; 90(4):1986-91. View in: PubMed

Gestational diabetes mellitus. J Clin Invest. 2005 Mar; 115(3):485-91. View in: PubMed

Novel human alpha1a-adrenoceptor single nucleotide polymorphisms alter receptor pharmacology and biological function. Naunyn Schmiedebergs Arch Pharmacol. 2005 Mar; 371(3):229-39. View in: PubMed

Association between monocyte Fcgamma subclass expression and acute coronary syndrome. Immun Ageing. 2004 Nov 12; 1(1):4. View in: PubMed

Changes in insulin sensitivity in response to troglitazone do not differ between subjects with and without the common, functional Pro12Ala peroxisome proliferator-activated receptor-gamma2 gene variant: results from the Troglitazone in Prevention of Diabetes (TRIPOD) study. Diabetes Care. 2004 Jun; 27(6):1365-8. View in: PubMed

Pharmacological treatment of insulin resistance at two different stages in the evolution of type 2 diabetes: impact on glucose tolerance and beta-cell function. J Clin Endocrinol Metab. 2004 Jun; 89(6):2846-51. View in: PubMed

Frequency of EEG abnormalities in age-matched siblings of autistic children with abnormal sleep EEG patterns. Epilepsy Behav. 2004 Apr; 5(2):159-62. View in: PubMed

Complex distribution, not absolute amount of adiponectin, correlates with thiazolidinedione-mediated improvement in insulin sensitivity. J Biol Chem. 2004 Mar 26; 279(13):12152-62. View in: PubMed

A large set of Finnish affected sibling pair families with type 2 diabetes suggests susceptibility loci on chromosomes 6, 11, and 14. Diabetes. 2004 Mar; 53(3):821-9. View in: PubMed

Changes in thrombolytic and inflammatory markers after initiation of indinavir- or amprenavir-based antiretroviral therapy. Cardiovasc Toxicol. 2004; 4(2):179-86. View in: PubMed

Time from diagnosis of type 2 diabetes to initiation of insulin therapy is related to carotid artery intima-media thickness. Atherosclerosis. 2003 Oct; 170(2):293-9. View in: PubMed

Fasting plasma glucose test at the first prenatal visit as a screen for gestational diabetes. Obstet Gynecol. 2003 Jun; 101(6):1197-203. View in: PubMed

C-reactive protein and glycemic control in adults with diabetes. Diabetes Care. 2003 May; 26(5):1535-9. View in: PubMed

Increased platelet Fc receptor expression as a potential contributing cause of platelet hypersensitivity to collagen in diabetes mellitus. Br J Haematol. 2003 Apr; 121(1):139-42. View in: PubMed

Prevention of type 2 diabetes: what is it really? Diabetes Care. Prevention of type 2 diabetes: what is it really? Diabetes Care. 2003 Apr; 26(4):1306-8. View in: PubMed

Counterpoint: glucose monitoring in gestational diabetes: lots of heat, not much light. Diabetes Care. 2003 Mar; 26(3):948-9. View in: PubMed

Pancreatic beta-cell loss and preservation in type 2 diabetes. Clin Ther. 2003; 25 Suppl B:B32-46. View in: PubMed

Preservation of pancreatic beta-cell function and prevention of type 2 diabetes by pharmacological treatment of insulin resistance in high-risk hispanic women. Diabetes. 2002 Sep; 51(9):2796-803. View in: PubMed

Prospective, intensive study of metabolic changes associated with 48 weeks of amprenavir-based antiretroviral therapy. Clin Infect Dis. 2002 Aug 15; 35(4):475-81. View in: PubMed

The ratio of plasminogen activator inhibitor type-1 activity to the concentration of plasminogen activator inhibitor type-1 protein in diabetes: adding insult to injury. Coron Artery Dis. 2002 Aug; 13(5):275-81. View in: PubMed

Variation in three single nucleotide polymorphisms in the calpain-10 gene not associated with type 2 diabetes in a large Finnish cohort. Diabetes. 2002 May; 51(5):1644-8. View in: PubMed

Heritability of subclinical atherosclerosis in Latino families ascertained through a hypertensive parent. Arterioscler Thromb Vasc Biol. 2002 May 01; 22(5):843-8. View in: PubMed

Clinical predictors for a high risk for the development of diabetes mellitus in the early puerperium in women with recent gestational diabetes mellitus. Am J Obstet Gynecol. 2002 Apr; 186(4):751-6. View in: PubMed

High-risk teen compliance with prescription contraception: an analysis of Ohio Medicaid claims. J Pediatr Adolesc Gynecol. 2002 Feb; 15(1):15-21. View in: PubMed

The effects of varying doses of T on insulin sensitivity, plasma lipids, apolipoproteins, and C-reactive protein in healthy young men. J Clin Endocrinol Metab. 2002 Jan; 87(1):136-43. View in: PubMed

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