Sub-diabetic glucose levels predict CVD
medwireNews: Researchers report a linear association between random plasma glucose levels and the risk of subsequent cardiovascular disease (CVD) in people without diabetes.
The increased risk extended down to categories of plasma glucose well below glucose levels associated with diabetes, report Zhengming Chen (University of Oxford, UK) and colleagues.
They say their findings therefore “support consideration of blood glucose levels as a continuous variable (rather than simply the presence or absence of diabetes) in cardiovascular risk prediction models and suggest the need to consider CVD primary prevention at glucose levels below the diabetes threshold.”
Indeed, during an average 7 years of follow-up, people with plasma glucose levels of just 4.3–5.2 mmol/L had a significant 7% increased risk of major occlusive vascular disease and an 8% increased risk of ischaemic stroke, relative to people with levels below 4.3 mmol/L.
None of the 467,508 participants, who were aged an average of 50.9 years and drawn from a Chinese population-based study, had diabetes or CVD at baseline. But during follow-up there were 6645 cardiovascular deaths, 3270 major coronary events, 19,153 ischaemic strokes, 22,023 cases of major occlusive vascular disease and 4326 intracerebral haemorrhages.
The risk of cardiovascular death was significantly increased from a glucose level of 5.8–6.7 mmol/L, by 10%, and the risk of all outcomes except intracerebral haemorrhage was increased from a level of 6.8–7.7 mmol/L. Intracerebral haemorrhage risk increased only at levels of 11.1 mmol/L and above.
All associations were independent of educational attainment, smoking, alcohol intake, physical activity and blood pressure and persisted after excluding people with glucose levels in the diabetic range and those who developed diabetes during follow-up. And all associations were linear, with no sign of a threshold effect, the researchers note in JAMA Cardiology.
Overall, each 1 mmol/L increase in participants’ usual plasma glucose level (estimated from retests after an average of 2.6 years) was associated with a significant risk increase of 11% for cardiovascular death, 10% for major coronary events and 8% for ischaemic stroke and major occlusive vascular disease. For myocardial infarction and ischaemic stroke the associations were larger for fatal than nonfatal events.
Study participants with random glucose levels in the prediabetes range were invited back for a fasting plasma glucose test. Using these data, Chen and team found that fasting and random plasma glucose values had similar linear associations with CVD outcomes.
“Fasting and postload blood glucose levels are arguably more robust glycemic measures than random blood glucose levels, which may be subject to greater interindividual and intraindividual variation”, they say. “However, nonfasting glucose levels may be more relevant to CVD risks because people spend most time in a nonfasting state.”
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