With only 5 days until my departure for Samoa, I thought it might be a good time to answer that question. I found the opportunity through one of my professors at Brown, who has been doing obesity and diabetes public health research in American Samoa for 30 years. A new research grant of his recently got turned down due to lack of proof that the research methods were feasible. Along with 4 other Brown undergrads, I'll be working to conduct a pilot study to ensure the feasibility of the two main methods in question.
The project studies energy expenditure and physical activity in American Samoan children, with the eventual goal of understanding if differences in children's activity levels have an impact on obesity trends in adulthood. This summer, we will conduct an abbreviated version of the study on a small sample of 30-40 children to ensure that we can effectively measure their energy expenditure and activity levels. We aren't concerned so much with random sampling or the actual analysis of the data so much as how well the data collection goes. For each participant, we will measure some basic anthropometric traits (height, weight, blood pressure, etc), carry out a doubly labeled water test, administer an activity monitor, and collect information on dietary intake. The activity monitor and doubly labeled water methods will be the two under the closest scrutiny.
The doubly labeled water (DLW) method involves giving the children a sample of water with two heavy isotopes (O18 and H2) and taking six urine samples over the course of 7 days. We will submit the samples to a mass spectrometry lab, which will give us the total energy expenditure for each participant. Using height and weight, we will estimate resting energy expenditure (the amount of energy your body uses just to stay alive) and subtract it from the total energy expenditure to get energy expenditure due to physical activity. This method is fairly commonly used now, but we must verify that it will work specifically among American Samoan children. Click Here for a more detailed description of DLW.
During the same 7 days we carry out the DLW method on each child, we will give him or her an electronic activity monitor to be worn night and day around the waist. The device works similar to a standad pedometer, but it records much more detailed records of the child's activity and allows us to view trends in physical activity. Combining this data with the DLW data should give us a good overall indication of each child's activity level and energy expenditure. The image to the right shows one of the activity monitors we will be using.
The project will certainly keep me busy for the summer. Even with five of us working, we will be following nearly 40 children for 7 days each - no easy task. However, working directly with the children should be both fun and educational, a great combination for a summer research project. Even though everything sounds very systematic, the realities of recruiting kids and getting them to go along with our crazy research endeavors will likely prove much more chaotic. I guess I'll know soon enough.