Add one more study to the growing mountain of data that points directly at higher than optimal blood sugars as a major cause of death.
A study in the November 11 issue of the Lancet - Global and regional mortality from ischaemic heart disease and stroke attributable to higher-than-optimum blood glucose concentration: comparative risk assessment, concluded "Higher-than-optimum blood glucose is a leading cause of cardiovascular mortality in most world regions."
In the WebMD article on the study, High Blood Sugar a Global Killer, the staggering number of deaths annually is laid out - Worldwide, high blood sugar is linked to 3,160,000 deaths each year.
Three million deaths annually!
Are we talking about blood sugars in the pre-diabetic (100-125mg/dL) or diabetic (126+/mg/dL) range?
No, this study demonstrated that even levels considered "normal" may be deadly over the long-term - as the WebMD article noted "High blood sugar is one sign that a person is on the road to diabetes. But it kills many people long before they ever get diabetes, note Goodarz Danaei, MD, of Harvard School of Public Health, and colleagues.
Moreover, blood sugar levels start causing problems once they pass the higher-than-normal level. It's not a matter of getting disease at a certain point. It's a matter of ever-increasing disease risk."
In this study risk started to increase at 4.9mmol - just 88.2mg/dL; well below the ADA "normal" of less than 100mg/dL; much less than the 100-125mg/dL for a diagnosis of pre-diabetes and much, much lower than the 126mg/dL used as the level to diagnose diabetes.
Quite frankly, this isn't news - we've had hard data for years warning us about the dire consequences of even a minor elevation in blood sugars within the normal range.
Archives of Internal Medicine, October 2004: Is nondiabetic hyperglycemia a risk factor for cardiovascular disease? A meta-analysis of prospective studies
CONCLUSION: Blood glucose level is a risk marker for CVD among apparently healthy individuals without diabetes.
Diabetes Care, December 2004: Blood glucose and risk of cardiovascular disease in the Asia Pacific region
CONCLUSIONS: Fasting blood glucose is an important determinant of CVD burden, with considerable potential benefit of usual blood glucose lowering down to levels of at least 4.9 mmol/l.
Archives of Internal Medicine, September 2005: Glycemic Control and Coronary Heart Disease Risk in Persons With and Without Diabetes
"...the RR of CHD for a 1–percentage point increase in HbA1c level was 2.36 (95% CI, 1.43-3.90) in persons without diabetes but with an HbA1c level greater than 4.6%. In diabetic adults, the RR was 1.14 (95% CI, 1.07-1.21) per 1–percentage point increase in HbA1c across the full range of HbA1c values."
"Our results also suggest that in persons without diabetes, a "high normal" HbA1c level predicts elevated CHD risk and that, in addition to diabetes prevention, strategies to lower glucose levels should be investigated for reducing heart disease risk."
Diabetes Care, 2006: Relation Between Blood Glucose and Coronary Mortality Over 33 Years in the Whitehall Study
"All-cause, cardiovascular, and respiratory mortality were elevated among participants with glucose intolerance...There was no evidence for a dose-response relationship below 2hBG = 4.6 mmol/l. Between this level and 11.1 mmol/l (200 mg/dl), the age-adjusted hazard ratio was 3.62 (95% CI 2.3–5.6)."
Add to this, impaired fasting glucose may not even begin to rise enough to alert clinicians before damage is occurring.
In 2003, the ADA journal Diabetes published a study, The Natural History of Progression From Normal Glucose Tolerance to Type 2 Diabetes, researchers found that of the 437 people who started out with normal glucose tolerance only 48% remained normal. Of the rest, 52% developed abnormal blood sugars during the course of the study. Critical in this data is the finding that 31% of the original group of 437 participants had impaired glucose tolerance though they still had "normal" fasting blood glucose. In fact, abnormal post-challenge blood sugar with normal fasting glucose was the most common pattern for developing type II diabetes in the study.
As noted on the What they Don't Tell You About Diabetes website - the difference in the range of "normal" blood sugar tests in telling. "At the outset of the study the average fasting plasma glucose of the people who remained normal was 82 mg/dl with a narrow standard deviation reaching up to 92 mg/dl. But the average fasting plasma glucose of the "normal" people who went on to develop diabetes was 10% higher--at 90 mg/dl but the standard deviation extended all the way up to 139 mg/dl, the pre-1998 ADA cut off for "normal." (The standard deviation is a measure of how tightly values in a range cluster around the mean.)"
It's difficult enough to grasp the ever increasing risk if you have diabetes; when you don't, it boggles the mind how your "normal" blood sugars might be killing you!
The take home message of this new study, when taken with others with similar findings is this - it isn't whether you have diabetes that decides your long-term risk for diabetes or cardiovascular disease, it's whether you have blood sugars above optimal, even within the normal range; the higher they are, the more the risk. As the data shows, higher than optimal blood sugars are those that doctors now treat as normal.