Propensity for Intra-abdominal and Hepatic Adiposity Varies Among Ethnic Groups

Abstract

We compared fat storage in the abdominal region among individuals from 5 different ethnic-racial groups to determine whether fat storage is associated with disparities observed in metabolic syndrome and other obesity-associated diseases. We collected data from 1794 participants in the Multiethnic Cohort Study (60-77 years old; of African, European [white], Japanese, Latino, or Native Hawaiian ancestry) with body mass index values of 17.1-46.2 kg/m2. From May 2013 through April 2016, participants visited the study clinic to undergo body measurements, an interview, and a blood collection. Participants were evaluated by dual-energy x-ray absorptiometry and abdominal magnetic resonance imaging. Among ethnic groups, we compared adiposity of the trunk, intra-abdominal visceral cavity, and liver, adjusting for total fat mass; we evaluated the association of adult weight change with abdominal adiposity; and we examined the prevalence of metabolic syndrome mediated by abdominal adiposity. Relative amounts of trunk, visceral, and liver fat varied significantly with ethnicity-they were highest in Japanese Americans, lowest in African Americans, and intermediate in the other groups. Compared with African Americans, the mean visceral fat area was 45% and 73% greater in Japanese American men and women, respectively, and the mean measurements of liver fat were 61% and 122% greater in Japanese American men and women. The visceral and hepatic adiposity associated with weight gain since participants were 21 years old varied in a similar pattern among ethnic-racial groups. In the mediation analysis, visceral and liver fat jointly accounted for a statistically significant fraction of the difference in metabolic syndrome prevalence, compared with white persons, for African Americans, Japanese Americans, and Native Hawaiian women, independently of total fat mass. In an analysis of data from the participants in the Multiethnic Cohort Study, we found extensive differences among ethnic-racial groups in the propensity to store fat intra-abdominally. This observation should be considered by clinicians in the prevention and early detection of metabolic disorders.