Death Risk Rises With Blood Sugar
Even Without Diabetes, High Blood Sugar Ups Death, Heart Disease Risk
High HbA1c Risky for Everybody
If you don't have diabetes, your blood sugar is still an issue. A huge issue, find Kay-Tee Khaw, MD, and colleagues at the University of Cambridge School of Clinical Medicine, England.
Khaw's team checked HbA1c levels in more than 10,000 45- to 79-year-old men and women for six years. Their findings:
- 72% of deaths were in people with HbA1c levels between 5% and 6.9%.
- The lowest rates of heart disease and death were among those with HbA1c levels under 5%.
- For men, every 1% increase in HbA1c beyond 5% meant a 24% increase in risk of death from all causes.
- For women, every 1% increase in HbA1c beyond 5% meant a 28% increase in risk of death from all causes.
- Even after taking into account traditional risk factors for heart disease, like high blood pressure, cholesterol, and previous heart attacks, there was a 21% increased risk of cardiovascular disease for every 1% increase in HbA1c beyond 5%.
"About 4% of the population have diabetes and [only] 27% of the population have HbA1c levels less than 5% -- so the majority of the population have HbA1c levels that are less than optimal," Khaw tells WebMD in an email interview.
Some people without diabetes are at higher risk than some people with diabetes, notes Hertzel C. Gerstein, MD, of McMaster University in Hamilton, Ontario.
"An HbA1c level of 6.59% in a non-diabetic individual predicts a higher cardiovascular risk than an HbA1c level of 5.5% in a well-controlled diabetic individual," Gerstein writes in an editorial accompanying the Khaw and Selvin studies.
Epidemic Heart Disease Looms
There's evidence that Americans' and Canadians' HbA1c levels are going up. Even a small increase in our average blood sugar levels -- of 0.1% to 0.2% -- means the nation faces a massive epidemic of heart disease.
"But this epidemic is not inevitable -- it may be thwarted if we take action now," Gerstein writes. "We know that lifestyle changes can dramatically reduce the incidence of diabetes and slow the HbA1c increase in both non-diabetic and diabetic individuals."
Meanwhile, Sperling urges primary care doctors to pay close attention to patients' blood sugar levels and other heart risk factors. Just because a person doesn't have full-blown diabetes, full-blown high blood pressure, or very high cholesterol doesn't mean they don't need help.
"Average Joe America goes to his doctor and hears he has borderline high blood pressure, his bad cholesterol is a little high, his good cholesterol is a little low, his blood sugar is getting up there -- no red flags, just borderline," Sperling says. "But now we know that being borderline carries a significant risk. Doctors have to recommend realistic lifestyle changes and consider medications to lower these risks."