Insulin sensitivity and plasma homocysteine concentrations in non-diabetic obese and normal weight subjects.
OBJECTIVE
To determine whether plasma homocysteine (tHcy) levels were related to insulin resistance and obesity in subjects without diabetes or vascular disease.


METHODS
We studied correlates of plasma tHcy in 26 subjects covering a wide spectrum of obesity and insulin sensitivity (S(I)). The measurement of in vivo insulin sensitivity was performed using the minimal model analysis of the frequently sampled intravenous glucose tolerance test (FSIVGTT).


RESULTS
There was no relationship between tHcy and body mass index. There was a significant relationship between plasma tHcy and S(I) (r=0.53, P=0.006), demonstrating that the more insulin sensitive subjects had higher levels of tHcy. On log transformation of the plasma insulin values, log insulin correlated negatively with plasma tHcy (r=-0.47; P=0.02). None of the subjects were deficient in vitamin B(12) and folate. Plasma vitamin B(12) was significantly related to plasma tHcy (r=-0.44, P=0.017), although we found no significant relationship between plasma folate and tHcy (r=-0.21, P=0.27). S(I) correlated significantly with vitamin B(12) (r=0.4, P=0.045) whereas, we found no significant relationship between S(I) and plasma folate (r=0.27, P=0.2). On multiple linear regression using tHcy as the dependent variable, S(I) and vitamin B(12) remained significant predictors of plasma tHcy, whereas, age and plasma folate were not predictors of tHcy.


CONCLUSIONS
We conclude that in vitamin replete lean and obese individuals, insulin sensitivity correlates significantly with plasma tHcy. This relationship may need to be considered when evaluating the role of plasma homocysteine as a risk factor in patients with obesity and type 2 diabetes.
Fonseca
Vivian A
VA
Section of Endocrinology, Tulane University Health Sciences Center, New Orleans VA Hospital, LA, USA.
Fink
Louis M
LM
Kern
Philip A
PA
D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D015992:Body Mass Index; D016022:Case-Control Studies; D015331:Cohort Studies; D003922:Diabetes Mellitus, Type 1 / Q000150:complications / Q000175:diagnosis* / Q000188:drug therapy; D005260:Female; D005951:Glucose Tolerance Test; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D007333:Insulin Resistance; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009765:Obesity / Q000097:blood / Q000150:complications / Q000175:diagnosis*; D011336:Probability; D012016:Reference Values; D012680:Sensitivity and Specificity
D001786:Blood Glucose; D006710:Homocysteine