The findings emphasize the need to increase efforts to prevent diabetes, researchers report in a study published in The Lancet.
The results of the study are also being presented at the American Diabetes Association's 70th annual scientific sessions in Orlando, Fla.
British scientists analyzed data on nearly 700,000 people, each of whom had been monitored for about 10 years in 102 surveys in 25 countries.
Other key findings include:
- Blood glucose levels alone should not be used to help identify people at increased risk of heart disease or stroke.
- Diabetes may cause damage through additional routes than obesity, blood fats, and blood pressure.
- Higher than average fasting blood glucose levels are only weakly related to later development of heart attacks or strokes.
"Our findings highlight the need for better prevention of diabetes coupled with greater investigation of the mechanisms by which diabetes increases the risk of cardiovascular disease," Nadeem Sarwar, PhD, of the University of Cambridge, says in a news release.
"Information on age, sex, smoking habits, blood pressure and blood fats is routinely collected to assess risk of developing cardiovascular disease. Our findings indicate that adding information on fasting blood glucose levels in people without diabetes does not provide significant extra help in assessing cardiovascular risk."
Hertzel C. Gerstein, MD, MSc, FRCPC, of McMaster University and Hamilton Health Sciences in Ontario, Canada, writes in an accompanying editorial that the relationship between blood sugar levels above the normal range and vascular outcomes could be linked to a wide range of other factors, such as lipid metabolism, fat deposition into tissue, and liver function.
"Any or all of these factors and others might promote cardiovascular disease through various known and unknown mechanisms," Gerstein says in a news release. "Large long-term clinical trials of insulin-replacement therapy, incretins [hormones that increase insulin output] and other approaches targeting one or more of these abnormalities that are either underway or about to start are certain to shed more light on the link between dysglycemia and serious outcomes."
The study also shows that:
- Cardiovascular disease is responsible for some 17 million deaths annually, worldwide.
- Coronary heart disease risks were higher in women than in men 40-59 than at age 70 and older.
The researchers write that the findings were consistent across all groups of people in the 25 countries from which data was analyzed.
Danesh and Gerstein disclosed receiving funds for various services from the pharmaceutical industry.