The Southall and Brent Revisited (SABRE) study is a large-scale population-based investigation by researchers at Imperial College London. It has followed 4200 middle-aged Londoners of European, South Asian and African Caribbean descent since 1988. The new findings, published in Diabetes Care found that by age 80, twice as many South Asian, Black African and African Caribbean men and women had developed type 2 diabetes (T2D) compared with Europeans of the same age.
Dr Therese Tillin, from the National Heart and Lung Institute at Imperial, 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 researchers found that black Africans, African Caribbeans and white Europeans tend to be diagnosed at around the same age (66–67 years), whereas South Asian men were 5 years younger on average at diagnosis. They looked at a number of risk factors, including family history, insulin resistance and abdominal fat.
Although over half of South Asian, African and African Caribbean men and one third of women had a family history of diabetes, this did not explain the extra risk over their European counterparts. However, higher body fat levels (especially around the waist) and insulin resistance explained the increased risk of T2D in South Asian and African Caribbean women. However, this explained only part of the risk in South Asian and African Caribbean men, suggesting that other risk factors, which are as yet unknown, may also play a part. More research is needed into risk factors which may act at different stages of life in order to fully explain why South Asian, African and African Caribbean men and women are at such high risk of developing diabetes.
Research leader Professor Nish Chaturvedi said: “We set up the SABRE study in 1988 and it is one of the largest and longest running tri-ethnic cohorts in the UK. We plan to extend our research to examine the roles of genes and the environment at different stages of life in causing diabetes in the three ethnic groups.”
SABRE is partly funded by the British Heart Foundation, and Research Advisor Dr Helene Wilson commented: “This study suggests the higher rate of diabetes – a major risk factor for heart attacks and strokes – in some South Asian and African Caribbean women is due to increased levels of obesity, particularly the build-up of fat around the waist, and higher resistance to insulin, which helps the body process sugar. This is a very encouraging discovery because it underlines the fact that controlling your weight by eating well and getting active can have a significant protective effect on your health. There’s a wealth of existing evidence that keeping the weight off by eating a healthy balanced diet and being physically active will reduce your risk of heart disease and type 2 diabetes, whatever your ethnic group.”
