According to the study, when it comes to blood sugar levels within the normal range, it is a case of the lower the better in protecting against CVDs.
Raised blood sugar levels could be linked to a greater risk of heart diseases, research suggests.
The study found that men and women with raised blood sugar levels have a 30-50% increased chance of developing cardiovascular diseases even when these levels are below the threshold for diabetes.
Among those with diabetes, women’s higher risk of developing any cardiovascular disease (CVD), compared with men, disappeared once factors such as body measurements and medication were taken into account, the researchers found.
They also discovered evidence that for blood sugar levels within the normal range, it was a case of the lower the better in protecting against CVDs, which include heart attacks and strokes.
Compared with people with normal blood sugar levels, those with the lowest levels had a 10% lower risk of developing any form of CVD.
Men with raised blood sugar below the threshold for diabetes had a 30% greater risk of developing CVDs.
Women with raised blood sugar below the threshold for diabetes had between a 30-50% greater risk of developing the diseases.
According to the findings, the risks were as much as doubled in those with diagnosed diabetes.
Lead author Dr Christopher Rentsch, from the London School of Hygiene and Tropical Medicine (LSHTM), said: “This work represents a meaningful step forward from decades of research on diabetes and heart disease.
“We quantified differences in the risk of heart disease between men and women across the full range of blood sugar levels.
“What we discovered is that those risks are not only confined to people with diagnosed diabetes, that men and women with prediabetes are also significantly affected.
“Our team also uncovered compelling evidence that within the ‘normal’ blood sugar range, a lower level appears to be better for protecting against heart disease.”
Senior author Professor Krishnan Bhaskaran, from the LSHTM, said: “Our results suggest that the increased risks seen in both men and women could be mitigated through modifiable factors, including weight reduction strategies and greater use of antihypertensive and statin medications.
“This is an important new insight that should help guide future public health strategies.”
The study analysed UK Biobank data from 427,435 UK people (54.2% women, 45.8% men), including people with normal blood sugar levels, those with prediabetes, and those with diabetes.
The research found that more men than women used high blood pressure medications and statins, suggesting women are not prescribed these preventative medications at the same rate as men with similar blood sugar levels.
The researchers say a study focusing on the factors behind this gap is needed.
The study published in The Lancet Regional Health – Europe was led by researchers at the LSHTM and University College London (UCL).
Robert Storey, professor of cardiology and cardiovascular disease theme lead at the University of Sheffield, said: “The study provides support for a strategy of assessing cardiovascular risk in people who are overweight, including assessment of blood sugar, cholesterol and blood pressure levels, all of which can be effectively managed to markedly reduce the risk of future heart attack and stroke.”
Dr Lucy Chambers, head of research communications at Diabetes UK, said: “This important new research, co-funded by Diabetes UK and the British Heart Foundation, highlights strategies that could tackle sex-based inequalities in cardiovascular disease outcomes, including greater use of antihypertensive and statin medications in women.
“The research is also an important reminder that having higher than normal blood sugar levels over long periods damages blood vessels, increasing risk of cardiovascular diseases, and that this effect can be seen not only in people with diabetes but also prediabetes.”