Research - Hoogeveen

High homocysteine increases the risk of death, especially in type 2 diabetes 5-year Follow up of the Hoorn Study

Background
Cardiovascular disease is the major cause of death in diabetic and nondiabetic subjects. The overall and cardiovascular mortality rates are 2 to 4 times higher in type 2 diabetes patients than in nondiabetic subjects. This is not fully explained by conventional risk factors.

Elevated homocysteine is a recently recognized independent risk factor for cardiovascular disease. Although the mechanisms by which homocysteine promotes atherothrombosis are unknown, the association between elevated homocysteine and atherothrombotic disease is strong.

A recent study suggested that the association between total homocysteine and cardiovascular disease is stronger in diabetic than in nondiabetic subjects.

Why did the researchers do this particular study?
To investigate the combined effect of elevated homocysteine and type 2 diabetes on mortality.

Who was studied?
2484 men and women, 50 to 75 years of age, who were randomly selected from the town of Hoorn, the Netherlands

How was the study done?
Fasting serum total homocysteine levels were measured in
- 171 subjects who died
- 640 survivors
Mortality risks were calculated over 5 years of follow-up.

What did the researchers find?
- The prevalence of elevated homocysteine or Hyperhomocysteinemia (tHcy > 14 _mol/L) was 25.8%
- The odds ratio for 5-year mortality was over 150% for Hyperhomocysteinemia and over 120% per 5 micromole increment of total homocysteine.
- The odds ratio for mortality for Hyperhomocysteinemia was over 130% in nondiabetic subjects and over 250% in diabetic subjects

What are the implications of the study?
Elevated homocysteine is related to 5-year mortality independent of other major risk factors and appears to be a stronger risk factor for mortality in type 2 diabetic patients than in nondiabetic subjects.

Reference: Hoogeveen EK et al. Hyperhomocysteinemia Increases Risk of Death, Especially in Type 2 Diabetes, 5 ÐYear Follow-up of the Hoorn Study. Circulation. 2000; 101:1506-1511.

HOMOCYSTEINE FACT:

Lowering homocysteine concentrations by 3 umol/l from current levels (achievable by increasing folic acid intake) would reduce the risk of ischaemic heart disease by 16%, deep vein thrombosis by 25%, and stroke by 24%.