Truncal fat in relation to total body fat: influences of age, sex, ethnicity and fatness

Abstract

Objective: To investigate the influence of age, sex, ethnicity and total fatness on central obesity in four ethnic populations. Design: Cross-sectional analysis of study subjects enrolled from 1993 to 2005. Subjects: A multi-ethnic (Caucasian (CA), African-American (AA), Hispanic-American (HA) and Asian (As)) convenience sample of 604 men and 1192 women (aged 18–96 years, body mass index 15.93–45.80 kg/m²). Measurements: Total body fat (TBF) and truncal fat were measured by dual-energy X-ray absorptiometry. General linear regression models were used to test for independent associations with log₁₀-transformed truncal fat. Results: For all ethnicities, men had a lower percent body fat and more truncal fat than women. Log_10-transformed truncal fat increased with TBF approximately as a square root function. At older ages, there was a greater amount of truncal fat in CA, HA and As men (∼0.20–0.25 kg/decade) with the effect more pronounced in AA men (∼0.33 kg/decade). For women, the increment of truncal fat per decade was reduced in CA and AA women (∼0.07 kg) compared with As and HA women (∼0.33 kg). Adjusted for mean values of covariates in our sample, AA had less truncal fat than As. Conclusion: The accumulation of truncal fat is strongly related to age, ethnicity and total fatness in both men and women.