Diabetes and risk of cardiovascular disease

From an interesting study about a subject I’ve wondered about from time to time:

“OBJECTIVE—To compare the risk of cardiovascular disease (CVD) death and the impact of hyperglycemia on the risk of CVD mortality associated with type 1 diabetes to that associated with type 2 diabetes.

RESULTS—During an 18-year follow-up, 86 participants with type 1 diabetes, 567 participants with type 2 diabetes, and 252 nondiabetic participants died. CVD mortality rates per 1,000 person-years were 23.1 (95% CI 16.9–31.9) in type 1 diabetic, 35.3 (30.8–40.4) in type 2 diabetic, and 4.6 (3.8–5.7) in nondiabetic participants. Adjusted hazard ratios for CVD mortality in participants with type 1 diabetes versus no diabetes was 3.6 (95% CI 2.2–5.7) in men and 13.3 (6.9–22.5) in women and in participants with type 2 diabetes versus no diabetes 3.3 (2.5–4.5) in men and 10.1 (6.7–17.4) in women. An increment of 1 unit (%) of GHb increased CVD mortality by 52.5% (95% CI 28.4–81.3) in type 1 diabetic subjects and by 7.5% (4.3–10.8) in type 2 diabetic participants.

CONCLUSIONS—The impact of type 1 and type 2 diabetes on CVD mortality was similar. The effect of increasing hyperglycemia on the risk of CVD mortality was more profound in type 1 than in type 2 diabetic subjects.”

Do note that the age of onset of diabetes was >30 years in both groups, so the relevance of the results when it comes to my own situation (diagnosis at the age of 2) is still questionable. Of course this is only speculation on my part, but one reason I can think of why the impact of hyperglycemia is ‘more profound in type 1’ patients might be that type 2 diabetics already have a lot of risk factors (obesity, ‘life style’, ect.), so that the effect of one more risk factor mean marginally less than it does among type 1 patients. If you’re already fat and sedentary and have been for many years, which most type 2 patients statistically are, adding hyperglycemia will not impact your risk of CVD-risk much, as it’s probably already through the roof; if you’re a sedentary type 2 diabetic with a BMI > 30 who also smokes daily, we’re not talking about the likelihood of dying from CVD, we’re only talking about when it’ll happen.

The part below is a good way to illustrate that the two diseases, type 1 and type 2 diabetes, are not all that similar, or at least that the patients are not all that similar:

“At baseline type 1 diabetic participants, when compared with nondiabetic participants, were leaner and had higher HDL cholesterol and lower diastolic blood pressure, but they had a slightly higher prevalence of hypertension, higher systolic blood pressure, and higher content of urinary protein than nondiabetic participants. Type 2 diabetic participants, when compared with nondiabetic participants were older, heavier, and more often nonusers of alcohol and had a higher frequency of hypertension, higher systolic and diastolic blood pressure, lower HDL cholesterol, higher triglycerides, higher content of urinary protein, and higher estimated creatinine clearance. Type 1 diabetic participants, when compared with type 2 diabetic participants were younger, leaner, and less frequently nonusers of alcohol and had lower prevalence of hypertension, lower diastolic and systolic blood pressure, higher HDL cholesterol, lower triglycerides, longer duration of diabetes, and lower estimated creatinine clearance.”

Some of these differences are probably sample-related, but not all of them. Note that despite being leaner and having more of the ‘good cholesterol’, type 1 diabetics still had worse kidney function than ‘healthy people’. That kidney damage is disease-related, not life-style related, and it’s quite likely that the patients had higher HDL cholesterol (and were leaner?) because they on average eat (live?) healthier than people who aren’t sick – that’s after all what they’re supposed to do. The ‘diabetic = fat guy who asked for it’ heuristic doesn’t work when we’re talking about the type 1s.


August 7, 2010 - Posted by | Cardiology, Diabetes, Medicine, Nephrology, Studies

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