Ongoing Ancillary Studies

Body Fat Imaging Study 2

We learned a lot from the Body Fat Imaging Study 1 (BIS1) – mainly, how body fat distribution tends to differ by one’s race and ethnicity and how important for health it is to have lower amounts of fat in the abdominal visceral area and in the liver – regardless of body weight. The frequency of obesity-related fatty liver disease continues to rise. Currently, it is found in over one third of US adults including some with a normal body weight. Hawaiʻi ranks 2nd, and California 3rd, among the US states in terms of rate of new liver cancer diagnoses. In light of these, we will re-examine some of the BIS1 participants for their liver health in a new follow-up study (BIS2), supported by the National Institute on Minority Health and Health Disparities. Participants will undergo an abdominal MRI scan and blood and stool sample collections as in BIS1, and also liver fibrosis measurements using FibroScan and MR Elastography. We aim to study how liver fat changes over time, what drives liver injury or fibrosis among people with fatty liver, how some aspects of diet exacerbate or moderate changes in liver fat or fibrosis over time, and whether some gut bacteria are involved.

The Multiethnic Cohort-COVID-19 Project - CLOSED

The rapid pace at which the COVID-19 pandemic is unfolding poses a great challenge to collecting robust population-based data to address this health crisis. Because the Multiethnic Cohort (MEC) is community-based and includes a broad diversity of ethnic/racial groups, it offers a unique opportunity to collect data representing the full breadth of disease severity and population subgroups among older adults in Hawaiʻi and Los Angeles. We are sending invitation to MEC participants to answer a web-based questionnaire to collect data on risk factors and symptoms, as well as on the effects of the pandemic on their daily life. We are also asking them to download and use a COVID-19 symptom tracker mobile application as part of an international consortium of epidemiologic cohorts, the COronovirus Pandemic Epidemiology (COPE) consortium ( These data will be linked back to the very detailed demographic, lifestyle, clinical, geospatial, genetic and biomarker data already available on MEC members. This rapid epidemiologic data collection will be critical for a data-driven response to this and future public health crises.

Mechanisms of Ethnic/Racial Differences in Lung Cancer Due to Cigarette Smoking - HAWAIʻI ONLY - CLOSED

Worldwide, lung cancer is still the most common cancer and the leading cause of cancer-related deaths. Cigarette smoking remains the primary risk factor for this disease, however, only 15-20% of smokers will develop lung cancer. We have learned from the Multiethnic Cohort (MEC) Study that on the average and for the same quantity of cigarette smoke, compared to white smokers, Native Hawaiian smokers have a 50% greater risk of developing lung cancer; whereas, Japanese American smokers have a 25% lower risk of the disease. The purpose of this study is to better understand why the risk for developing smoking-related diseases varies among cigarette smokers, particularly between different ethnicities.

More about the new study at the UH Cancer Center

We hypothesize that ethnic/racial and individual differences in lung cancer risk are due to different biological responses to common tobacco lung toxicants. The objectives are to identify biomarkers that are associated with smoking-related lung cancer risk and to improve our understanding of the mechanisms underlying the ethnic/racial differences in lung cancer. These biomarkers are identified through analysis of blood, urine and saliva samples provided by study participants. The identification of risk biomarkers can aid in the development of targeted lung cancer screening efforts.

The study is recruiting 300 volunteers of Japanese, Caucasian or Hawaiian ancestry who are current cigarette smokers. The three ethnicities investigated in this study are well represented in Hawaiʻi. This research can benefit these populations by furthering our understanding of risk resulting from cigarette smoking and could lead to novel interventions within high risk populations.

Obesity, Body Fat Distribution and Cancer Risk - CLOSED

In the Multiethnic Cohort (MEC) Study, we have observed that Japanese Americans and Native Hawaiians are at higher risk of obesity‐related diseases, such as diabetes and certain cancers, compared to whites, for a given body size. We believe that these risk differences may be due in part to differences in where we accumulate fat within our body. In order to better understand body fat distribution and its relationship to disease, we are recruiting 2,000 MEC volunteers to look at this question in depth. In addition to evaluating body fat distribution through imaging, we are also studying gut bacterial populations to determine if these influence body fat patterns and risk of disease. This project has two substudies: the Body Fat Imaging Study and the Gut Microbiome Study.

Body Fat Imaging Study

In this part of the study, we are using surveys, blood measurements and DXA and MRI scans to find out how and why body fat distribution differs among men and women of Japanese, Hawaiian, European, African or Hispanic ancestry. Such a detailed study of multiple ethnic groups has never been done before, and this project can be best conducted in the Multiethnic Cohort. As always, we thank you for your participation in our research.

Learn more about Obesity Rates in the Multiethnic Cohort

Gut Bacteria (or Gut Microbiome) Study

One of the risk factors leading to obesity and increased abdominal fat may be certain profiles of bacterial populations that live in the gut. Recent studies found that intestinal bacteria are essential for the metabolism of energy and nutrients in the human hosts and that certain bacterial populations can extract up to an additional 15% of calories from the diet for their human hosts. In this part of the study, our goal is to determine how the types of intestinal bacteria found in stool are related to ethnicity, body weight, diet, lifestyle and genetics. The Multiethnic Cohort provides an ideal setting to conduct this type of innovative research. As always, we thank you for your participation.

Learn more about Gut Bacteria and Human Health

Brain-Gut Microbiome-Visceral Adiposity Relationships in Multiethnic Adults - CLOSED

The gut is referred to as the second brain for their close connection. The brain regulates the body's overall metabolism and affects the environment of intestinal bacteria. The gut microbes, in turn, have an effect on the brain by generating neuroactive compounds that are able to modify our mood and appetite. As part of the MEC Body Imaging Study above, this new project is investigating the structure, chemistry and neural connections within the brain using magnetic resonance imaging (MRI). These measurements will be related to gut microbes of individuals with low or high levels of intra-abdominal fat to see how certain bacteria and excess internal fat act together to affect the brain.