Dabeeru C. Rao, professor of biostatistics and director of the Division of Biostatistics, has received a four-year $1.8 million grant from the National Heart, Lung and Blood Institute (NHLBI) to coordinate a multi-center study on exercise, genetics and disease risk factors.
The grant will allow Rao and colleagues to search for genetic factors that give people an added benefit from regular exercise. Previous studies suggest that some exercisers only lose weight, whereas others also improve their heart rates and gain additional benefits that reduce the risk of cardiovascular disease or diabetes.
"If two similar neighbors do the same activity and respond differently, there must be genetic or environmental differences involved," Rao said. "We want to nail down the factors underlying these differences and determine how they interact."
He also hopes the study -- the first of its kind to look at families -- might suggest whether lifestyle or genetic differences play a more important role in the differing risks blacks and whites have for cardiovascular disease and diabetes.
The researchers will analyze genetic and health data obtained from 201 sedentary families that took part in the NHLBI-funded Heritage Family Study. These data were gathered by investigators at four field centers at the University of Indiana, Texas A&M University, the University of Minnesota, and Laval University in Quebec, Canada. Washington University and Laval University researchers now will identify those families that share a genetic tendency to gain a health benefit from exercise training in addition to losing weight. The investigators also will hunt for the genes responsible for this advantage.
During the initial five-year study, sedentary members of 103 black families and 98 white families followed a 20-week exercise program using stationary bikes. Each black family included at least two sedentary members -- two siblings or a parent and child -- and each white family had two sedentary parents and at least three sedentary children. The 745 volunteers exercised three times a week, and the training regimen became progressively longer and more difficult.
The data include measurements of blood pressure, heart rate, lipids, obesity and other indicators related to diabetes and cardiovascular function before and after the exercise program.
Rao and colleagues will work with the Quebec researchers to look for patterns that suggest a hereditary basis for additional health benefits from exercise. After analyzing data from individual family members, they will combine this information with family tree diagrams to clarify inheritance patterns. Treva Rice, Ph.D., research assistant professor of biostatistics; Ingrid Borecki, Ph.D., research associate professor of biostatistics; and Michael A. Province, Ph.D., associate professor of biostatistics, then will apply statistical models to explore the links between genetic and health data.
Rao and colleagues also will search for specific genes that might give some physically fit people greater protection from diabetes or cardiovascular disease.
The findings should be useful whether or not they reveal specific genes, Rao said. "Identifying beneficial genes could lead to the development of drugs or other therapies that reduce the risk of cardiovascular disease or diabetes," Rao said. "And if it turns out that certain environmental factors are critical, people can avoid the conditions that predispose them to these diseases and practice behaviors that improve their health."
