Raised blood glucose is associated with greater risk of cardiovascular disease (CVD) even when below the threshold for diagnosing diabetes, researchers have reported.
But women fare worse, which can largely be explained by modifiable risk factors including obesity and lower prescribing of antihypertensive medicines and statins.
Using data from the UK Biobank study researchers analysed the risk of coronary artery disease, atrial fibrillation, deep vein thrombosis, pulmonary embolism, stroke, heart failure or any cardiovascular disease (CVD) associated with varying blood glucose levels.
Overall, they found a 30-50% higher risk of developing CVD in people in the pre-diabetes (HbA1c 42-27mmol/mol) and undiagnosed diabetes (48mmol/mol or higher) categories as well as for those with the condition.
But the analysis of 427,435 people aged 40-69 years also identified key disparities between the sexes.
Men with raised blood glucose below the threshold for diabetes had a 30% greater risk of developing CVD but women in the same category had between 30-50% greater risk of CVD, the researchers reported in The Lancet Regional Health – Europe.
Yet women’s higher relative risk of developing any CVD than men was attenuated once factors such as body mass index, waist to hip ratio and medication use were taken into account.
Women had lower use of antihypertensive medications and statins than men, particularly in those who fell into normal and pre-diabetic categories, the researchers said.
In men with pre-diabetes 37.8% were prescribed a statin and 41.6% were on antihypertensive medication. For women in the same category the figures were 26.9% and 36%.
When it came to people within the ‘normal’ range (up to 41mmol/mol), the evidence suggested the lower the better for protection against cardiovascular disease.
The researchers say a study focusing on the factors behind this ‘prescribing gap’ between men and women is now needed.
It comes as the latest figures show the number of drug items prescribed for diabetes has increased by 16 million since 2015/16.
The cost of anti-diabetic medicines has also risen by 107% over the same period, the NHS Business Services Authority said.
Earlier this year the number of diabetes patients in the UK topped 5 million for the first time, a report from Diabetes UK warned.
Lead author Dr Christopher Rentsch from the London School of Hygiene and Tropical Medicine said: ‘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.’
Co-author Professor Krishnan Bhaskaran added: ‘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.’
Dr Stephen Lawrence, GP and associate clinical professor at the University of Warwick said it raised several interesting questions albeit from a population that was healthier than the average UK population.
‘This is very interesting observational study. For example, in my experience, if you look at the application of QRISK it underestimates the risk for women.’
He added that women seem to have to gain much more weight than men to tip them over biochemically into diabetes.
‘The data suggest there should be more aggressive focus on risk factors when prescribing for women who have diabetes. And it is not just about prescribing but also attending to lifestyle.’