Cardiovascular Burden of High Glucose Called Heavy

BOSTON, Nov. 10 -- Even if diabetes is left out of the equation, higher-than-optimum blood glucose is a major worldwide killer, according to researchers here.

More than one in five deaths from ischemic heart disease and one in eight deaths from stroke every year worldwide can be blamed on high blood glucose, calculated Goodarz Danaei, M.D., of Harvard Medical School, and colleagues.

When the nearly one million yearly deaths from diabetes are added in, the total mortality that can be blamed on higher-than-optimum blood glucose is 3.16 million worldwide, Dr. Danaei and colleagues reported in the Nov. 11 issue of The Lancet. This is comparable to other leading killers, such as smoking (4.8 million deaths a year) and high cholesterol (3.9 million).

"Higher-than-optimum blood glucose is a leading cause of cardiovascular mortality in most world regions," the researchers said, urging that cardiovascular risk and diabetes management programs "be more closely integrated rather than being in different spheres."

The finding emerged from a detailed analysis of individual-level data from population health surveys in the U.S., Australia, and Japan, as well as published systematic reviews and data provided by investigators, to create a picture of exposure data in 52 countries.

The researchers found:

• In 2001, there were 1.49 million deaths from ischemic heart disease and 709,000 from stroke which were attributable to high blood glucose, accounting for 21% and 13% of all deaths from these conditions.
• 1.8 million of these 2.2 million cardiovascular deaths (84%) were in low-and-middle-income countries.
• 792,000 (53%) of deaths from ischemic heart disease and 345,000 (49%) from stroke that were attributable to high blood glucose were in men.
• Also, there were 959,000 death directly from diabetes

More than three-quarters of the cardiovascular deaths occurred in poorer countries, the researchers noted, where resource limitations constrain management of higher-than optimum blood glucose.

In an accompanying editorial comment, Mauricio Avendano and Johan Mackenbach, M.D., Ph.D., both of Erasmus Medical Centre in Rotterdam, The Netherlands, said the findings "invite us to switch the focus from the dichotomous disease entity to a continuous exposure perspective."

The study also implies that population-based prevention approaches are needed, although exactly what form those efforts should take will require more research, they wrote.

But, they said, "pharmacological approaches should certainly not be our first choice" since randomized trials have demonstrated convincingly that lifestyle interventions are the most effective strategy.

That said, such intensive interventions have usually been tried among high-risk populations and it is not clear that they will translate easily to a mass basis, especially in the poorer countries, where the largest problem exists, they said.

Dr. Danaei and colleagues noted that their study has several limitations, including:

• The data were collected in varying forms and statistical models had to be used to codify them.
• The data cover only 74% of the world's population.
• Death rates are based on national databases, which were variable in terms of quality and comparability of coding.

They also pointed out that the study shows that an important consideration is co-exposure to high blood glucose and other cardiovascular risk factors. Because of multi-causality, levels or trends in total cardiovascular mortality, as a result of risks, would affect the absolute health effects of high blood glucose.

The patterns of these risk factors in developing and developed countries are different. For example, in Europe and Central Asia, the cardiovascular risks such as smoking, alcohol use, and high blood pressure, cholesterol, and body-mass index have led to high cardiovascular mortality. As a result, high blood glucose caused substantially more cardiovascular deaths in those regions than in Latin America and the Caribbean, where blood glucose levels were similar but cardiovascular mortality rates were lower.