Relationship between serum lipoprotein ratios and insulin resistance in obesity.
BACKGROUND
The fasting serum lipid profile [triglycerides (TGs), total cholesterol (TC), and LDL- and HDL-cholesterol (LDL-C and HDL-C)] is used to calculate lipid ratios (TC/HDL-C, LDL-C/HDL-C, TG/HDL-C) that allow identification of individuals at increased risk for cardiovascular disease. Because these individuals are also frequently insulin resistant, this study analyzed the relationships between lipid ratios and insulin sensitivity.


METHODS
In 132 obese [mean (SE) body mass index, 37.5 (0.6) kg/m(2)] outpatients without known diabetes mellitus, fasting serum lipid profiles and 75-g oral glucose tolerance tests were performed. Insulin sensitivity was assessed from surrogate estimates for fasting (QUICKI) and dynamic (OGIS) conditions.


RESULTS
After exclusion of other endocrine diseases (n = 35), the remaining patients were classified as glucose tolerant (n = 56), glucose intolerant (n = 22), or as having type 2 diabetes (n = 19). QUICKI and OGIS indicated severe insulin resistance in all individuals with type 2 diabetes and impaired glucose tolerance compared with glucose-tolerant individuals: QUICKI, glucose tolerant, 0.302 (0.002); glucose intolerant, 0.290 (0.002); type 2 diabetes, 0.281 (0.005); P <0.001; OGIS (mL . m(-2) . min(-1)), glucose tolerant, 343 (7), glucose intolerant, 293 (9); type 2 diabetes, 256 (12); P <0.001. Serum TG (P <0.005) and TG/HDL-C ratios (P <0.05) were increased in individuals with impaired glucose tolerance. TG/HDL-C ratios negatively correlated with QUICKI (r = -0.370; P < 0.001) and OGIS (r = -0.333; P < 0.005) in nondiabetic individuals (glucose tolerant plus glucose intolerant), but not in patients with type 2 diabetes (not significant).


CONCLUSIONS
This study demonstrates that the TG/HDL-C ratio positively correlates with insulin resistance in severely obese nondiabetic individuals.
Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria.
Attila
A
Brehm
Georg
G
Pfeiler
Giovanni
G
Pacini
Heinrich
H
Vierhapper
Michael
M
Roden
D000328:Adult; D002096:C-Peptide / Q000097:blood; D002784:Cholesterol / Q000097:blood*; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007333:Insulin Resistance; D008074:Lipoproteins / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000378:metabolism*; D014280:Triglycerides / Q000097:blood
D002096:C-Peptide; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D008074:Lipoproteins; D014280:Triglycerides; D002784:Cholesterol