The main interest of the Lindgren group's is to find out genetic factors that contribute to obesity and also factors which cause fat to build up in different areas of the body. Obesity occurs when the build up of body fat becomes harmful to an individual's health. Fat tends to accumulate on different parts of the body in different people; and each person can be generally placed into one of two broad categories: those who tend to accumulate fat around the abdomen (resulting in more of an "apple-shaped" body) and those whose fat is accumulated more around the hips and thighs (resulting in more of a "pear-shaped" body). We are interested in these differences in body fat distribution because having more abdominal fat (being more "apple-shaped" than "pear-shaped") has been linked to having a higher risk of developing coronary artery disease, stroke, type-2 diabetes, and some forms of cancer.
Obesity is commonly estimated using the body mass index (BMI). A person's BMI is calculated using a simple formula (weight in kilograms divided by the square of height in meters). A person is classified as obese if their calculated BMI is higher than 30. Additionally, different patterns of fat distribution can be represented using waist-hip-ratio (WHR) measurements (circumference of the waist divided by the circumference of the hips). A high WHR generally indicates increased abdominal fat.
Although it is widely recognized that there are environmental causes to obesity (such as availability of food, type of available food, choice of diet, exercise habits, climate, etc), there are also genetic causes, and the first few genes involved in both obesity (as measured by increased BMI) and increased abdominal fat accumulation (represented by high waist circumference or WHR) have recently been described.
We expect to achieve our research objectives by combining information resulting from:
a) Large-scale association studies which compare genetic variants in obese and in non-obese individuals. Finding the differences in these variants between those two groups helps to determine genes which increase the risk of obesity. These studies also have to take into account that fat distribution differs depending on age, between males and females, and potentially between different populations.
b) Studies of the differences in gene expression between obese vs. non-obese individuals. The differences in expression patterns between those two groups can help to determine the relationship between gene expression and differences in fat distribution.
We hope that the integration of these studies will help us understand ways in which specific biological mechanisms operate differently in obese and non-obese people. This understanding may eventually be used to develop new preventative, diagnostic, and therapeutic options to deal with the problems of obesity and its related complications.