Blood levels of total homocysteine in patients with type 1 diabetes (with no complications, diabetic nephropathy and/or retinopathy) and in their non-diabetic relatives.
OBJECTIVE
It has been reported that plasma homocysteine (Hcy) levels in type 1 diabetes (T1DM) patients without renal involvement are higher, similar to or lower than those in healthy controls.


RESULTS
We measured plasma Hcy in 60 controls, 79 type 1 diabetics (23 with retinopathy, 22 with nephropathy) and 73 non-diabetic relatives of 30 probands. The female controls had lower levels than their male counterparts: geometric mean 10.5 vs 13.6 mumol/L, p < 0.001. Among the controls, smokers (n = 20) and ex-smokers (n = 12) had higher Hcy levels than non-smokers (n = 28): 13.2 and 13.2 vs 10.9 mumol/L, p < 0.01. Among the diabetics, high plasma Hcy levels were associated with male gender: 11.9 vs 9.1 mumol/L in women, p < 0.01. The patients without complications had higher plasma glucose and hemoglobin A1c (HbA1c) levels (p < 0.001), and lower plasma Hcy (9.2 mumol/L vs 12.2, p < 0.01) and uric acid levels (p < 0.05) than the controls. The patients with nephropathy and higher levels of Hcy (13.0 mumol/L vs 9.0, p < 0.05), and different levels of creatinine (p < 0.01), uric acid (p < 0.01), fibrinogen (p < 0.05), and urinary albumin (p < 0.001) than those with retinopathy. There was no difference in Hcy levels between the patients' relatives and the controls: 11.9 mumol/L in siblings vs 11.6 mumol/L, 13.5 mumol/L in parents vs 12.1 mumol/L. In the control group, plasma Hcy levels were associated with age, gender and smoking; among the diabetics, they correlated with age, gender, smoking, and plasma creatinine and lipoprotein (a) levels.


CONCLUSIONS
1) male gender and smoking are associated with high Hcy levels in healthy people; 2) plasma Hcy levels are lower in T1DM patients than in healthy people (glomerular hyperfiltration and accelerated hepatic transsulfuration?); 3) high Hcy levels are associated with diabetic nephropathy and plasma creatinine levels; and 4) non-diabetic first-degree relatives of type 1 diabetics have normal plasma Hcy concentrations.
Matteucci
E
E
Department of Internal Medicine, University of Pisa, Italy.
Rossi
L
L
Mariani
S
S
Fagnani
F
F
Quilici
S
S
Cinapri
V
V
Giampietro
O
O
D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003404:Creatinine / Q000097:blood; D003430:Cross-Sectional Studies; D003922:Diabetes Mellitus, Type 1 / Q000097:blood*; D003928:Diabetic Nephropathies / Q000097:blood*; D003930:Diabetic Retinopathy / Q000097:blood*; D005260:Female; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012737:Sex Factors; D012907:Smoking / Q000097:blood
D006710:Homocysteine; D003404:Creatinine