Diabetes has been associated with an increased risk of heart attacks, stroke and kidney failure. A new study has found elevated blood sugar levels, even in people without diabetes, can increase the risk of heart disease.

The latest study by researchers from the London School of Hygiene and Tropical Medicine and University College London found high blood sugar levels in prediabetes patients can increase the risk of heart diseases such as heart failure by 30% to 47%.

Prediabetes is a condition in which patients have higher than normal blood sugar levels but not high enough to be considered type 2 diabetes. The symptoms include darkened skin on areas including the neck, armpits and groin. Prediabetes can progress to diabetes. However, the blood sugar levels in the patients can be efficiently managed by making lifestyle changes such as exercise and a healthy diet.

In the latest study, researchers evaluated the difference in the impact of elevated blood sugar levels in both men and women.

"We were interested to explore which risk factors drive known sex differences in the risk of heart disease between men and women with diabetes, and whether men or women with moderately elevated blood sugar below the threshold for diabetes are also at increased risk of heart disease," said Christopher Rentsch, a lead author of the study.

The team evaluated data from more than 427,000 participants of the UK Biobank (a long-term observational study) who were between 40 and 69 years. The participants were classified into low-normal, normal, prediabetes or diabetes based on their average blood sugar level in the three months before the study. Researchers tested them for heart diseases such as coronary artery disease, atrial fibrillation (AFib), deep vein thrombosis, pulmonary embolism, stroke and heart failure.

Men with increased blood sugar levels but below the diabetes threshold had a 30% greater risk of developing cardiovascular disease, while in women with the same blood sugar levels, the risk was between 30% and 50%.

"Our study represents a meaningful step forward from decades of research on the link between diabetes and heart disease, which has long asserted that men and women with diabetes have differential risks of heart disease," Rentsch said.

The difference in risk between men and women was reduced when researchers took into account obesity, a risk factor that can be modified with lifestyle changes.

"Key novel contributions of our work were quantifying the risk of heart disease across a full range of blood sugar levels for both men and women and demonstrating these associations were largely explained by modifiable factors," Rentsch added.