Dr. Maureen Murtaugh, Ph.D.

Associate Professor, Division of Clinical Epidemiology

Title: VALIDATION OF EARTH STUDY DIET HISTORY - NIH NATIONAL CANCER INSTITUTE

The major scientific goal of the AIAN Cohort Study is to determine how diet, physical activity, and other lifestyle and cultural factors relate to the development and progression of chronic diseases as well as relate to injuries, development of cataracts and other eye diseases, and age at time of death. Therefore, accurate measurement of the diet, physical activity, and other exposures over the past year is essential to the ability to detect meaningful relationships. The dietary history questionnaire (DHQ) provides a comprehensive assessment of foods and nutrients consumed and the results can relate to the individual. A self-administered-computer-assisted version of the DHQ has been developed for use in the Native American and Alaskan Indian Cohort study. However, neither the feasibility of using the self-administered-computer assisted DHQ referring to intake over the past year nor the validity of the DHQ for measuring dietary exposures have been established in American Indians and Alaska Natives. Most available reports are based on a single 24-hour recall that does not reflect usual individual intake and no published information was identified on individual or seasonal variability. The aim of this project is to assess the validity of the DHQ with regard to usual intake over the past year. Several components will be evaluated including: 1) relative validity of the self-administered-computer-assisted DHQ with regards to nutrient intake (sucrose, energy, fat, fiber), food consumption (vegetables and subsistence foods), and dietary patterns (western vs. traditional); 2) reproducibility (reliability) of the DHQ with regards to nutrient intake (sucrose, energy, fat, fiber, calcium, carotenoids), food consumption (vegetables and subsistence foods), and dietary patterns (western vs. traditional); 3) differences between computerized-self-administration versus paper and pencil self-administration of the DHQ on the estimates of nutrient intake (sucrose, energy, fat, fiber), food consumption (i.e. fruits, vegetables and subsistence foods), and dietary patterns (western vs. traditional, high vs. low glycemic index); 4) agreement of the DHQ with biomarkers measured at the initial clinic visit (glycemic index with serum insulin and glucose, dietary and serum lipids).

Title: NAVAJO BONE HEALTH STUDY - NIH NATIONAL CANCER INSTITUTE

The Navajo Bone Health Study aims to begin surveillance of bone health on the Navajo Nation. These efforts will in time enable the Navajo Nation to plan screening and culturally appropriate education and intervention programs targeted toward the segments of the population who are at greatest risk for fracture or osteoporosis. Specifically, we hypothesize that bone density (total bone mineral density (BMD), and BMD at the hip and lumbar spine) will be distributed differently in Navajo American Indians than Caucasians. We will examine this hypothesis by measuring BMD using dual energy x-ray absorptiometry (DXA) and heel ultrasound (BUA) and compare distributions and z-scores with those reported for Caucasians in the NHANES III database by age and gender groups. We aim to validate the use of BUA for bone health screening in Navajo Native Americans. We will examine the association of reported adult fractures with BMD measures (DXA and BUA) to relate these measures to a relevant public health outcomes. In addition we will examine the association of body size, diet (nutrients relevant to bone formation including calcium, vitamin D, Vitamin A and protein), and lifestyle (physical activity) factors to and BMD in Navajo adults and children over the age of 18. Data will be collected in a cross-sectional design coincident with the Navajo EARTH cohort study. DXA will be measured in 1296 randomly selected Navajo men and women. We will select 112 men and 112 women in four 10 year age groups (30-39,40-49,50-59, and 60 and older) to assure that we can adequately estimate BMD in each of these gender specific age groups separately. BMD BMD will be meaured using BUA in approximately 2500 Navajo men and women. This study is an important first step in surveillance of bone health of Navajo American Indians and make efficient use of the Navajo EARTH Cohort Study which is currently in the field (until March of 2007).