Obese "apple-shaped" women, who lay fat down on their stomachs, have a higher risk of developing type 2 diabetes and heart disease than overweight "pear-shaped" women who carry fat on their hips and thighs.
Although it is not known why some women are apple-shaped and others are pear-shaped, researchers at the University of Southampton believe that abnormalities in the way insulin works may provide the answer.
Insulin is a key hormone that controls the metabolism of carbohydrate, fat and protein in many tissues, including skeletal muscle, fat and the liver.
Dr. Richard Holt, of the UK's Southampton University Department of Fetal Origins of Disease, said: "There are very strong links between obesity and type 2 diabetes and heart disease. It is not just being obese that matters but where the fat is laid down.
"If you are apple-shaped you are much more likely to get these problems than if you are pear-shaped and the risks are higher for women than for men. We want to find out why that is.
"We believe a key factor is insulin resistance. We are looking at how insulin works in liver, fat and muscle in different shaped women and how important this is for development of disease."
The Southampton team led by Dr. Holt and Professor Chris Byrne aims to recruit 40 healthy, middle-aged, overweight women half of whom are apple-shaped and the other half pear-shaped.
Detailed body measurements will be taken and participants will complete physical activity and quality of life questionnaires. Blood tests will also enable doctors to look at insulin action and its relationship to fat and glucose metabolism.
A second part of the research will be done in collaboration with Dr. Richard Shreaves, consultant diabetologist and endocrinologist at Jersey General Hospital, also in the UK. It will examine the prevalence and likely health costs, both personal and financial, of central obesity among 300 middle-aged women on the island.
The study is being funded by a £50,000 grant from The States of Jersey Health and Social Services Committee through leading medical research charity, Hope.
Dr. Holt, senior lecturer in endocrinology and metabolism, added: "As central obesity is a major risk factor for type 2 diabetes, it is important to define precisely its prevalence.
"The association between central obesity and insulin resistance is unclear. An understanding may provide an insight into how type 2 diabetes and heart disease occurs and, in the future, provide strategies to reduce this health burden.
"Our hypothesis is there is difference in the way insulin works in different tissues between apple and pear-shaped obese women. If this is confirmed, we want to do further work to look at possible explanations which may underlie these differences."
It is estimated that 16 per cent of UK men and 17.5 per cent of women are obese. - By Kim d'Arcy
[Contact: Kim d'Arcy]