Half of all British people of South Asian, African and African Caribbean descent will develop type 2 diabetes by the age of 80, research suggests.
People of such heritage are twice as likely to develop the condition as their European neighbours, according to researchers.
The Southall and Brent Revisited (Sabre) study, which has followed 5,000 middle-aged Londoners of European, South Asian, African and African Caribbean descent for more than 20 years, found that only one in five Europeans will develop the disorder by age 80.
The study, funded by the Wellcome Trust and British Heart Foundation, also found that South Asian men were likely to be diagnosed an average of five years younger than people from other backgrounds.
Dr Therese Tillin, from the National Heart and Lung Institute at Imperial College, London, said: “Not only does this study increase our understanding of the reasons for ethnic differences in risks of diabetes, it highlights the astonishingly high risk of diabetes in middle-aged people in our ethnic minorities and the importance of early diagnosis and careful management.
“Future analyses will examine methods of predicting which individuals are most risk of diabetes - the good news is that diabetes can be prevented if the warning signs are recognised early enough.”
Dr Iain Frame, director of research at Diabetes UK, added: “People from these communities should be screened earlier than the general population - from the age of 25, rather than 40.
“While it is important for everyone to maintain a healthy weight, for people at high risk of developing type 2 diabetes - such as these groups - it is even more important to avoid being overweight and reduce their risk.”