Relationship between body fat and BMI in a US hispanic population-based cohort study: Results from HCHS/SOL

Abstract

Objective: To evaluate the percentage of body fat (%BF)-BMI relationship, identify %BF levels corresponding to adult BMI cut points, and examine %BF-BMI agreement in a diverse Hispanic/Latino population.

Methods: %BF by bioelectrical impedance analysis was corrected against %BF by (18) O dilution in 434 participants of the ancillary Hispanic Community Health Study/Study of Latinos. Corrected %BF was regressed against 1/BMI in the parent study (n = 15,261), fitting models for each age group, by sex, and Hispanic/Latino background; predicted %BF was then computed for each BMI cut point.

Results: Bioelectrical impedance analysis underestimated %BF by 8.7 ± 0.3% in women and 4.6 ± 0.3% in men (P < 0.0001). The %BF-BMI relationship was nonlinear and linear for 1/BMI. Sex- and age-specific regression parameters between %BF and 1/BMI were consistent across Hispanic/Latino backgrounds (P > 0.05). The precision of the %BF-1/BMI association weakened with increasing age in men but not women. The proportion of participants classified as nonobese by BMI but as having obesity by %BF was generally higher among women and older adults (16.4% in women vs. 12.0% in men aged 50-74 years).

Conclusions: %BF was linearly related to 1/BMI with consistent relationship across Hispanic/Latino backgrounds. BMI cut points consistently underestimated the proportion of Hispanics/Latinos with excess adiposity.

Trial registration: ClinicalTrials.gov NCT02060344.

Conflict of interest statement

Disclosure: The authors declare no conflict of interest. The contents of this publication do not necessarily reflect the views or policies of the USDA or the NIH, nor does mention of trade names, commercial products, or organizations imply endorsement.

© 2016 The Obesity Society.

Figures

Figure 1

Participant flow chart. HCHS/SOL, Hispanic Community Health Study/Study of Latinos (Parent study) and SOLNAS, Study of Latinos Nutrition & Physical Activity Assessment Study (Ancillary study of HCHS/SOL).

Figure 2

Relationship between percentage of body fat (%BF) assessed by the 18O dilution method and %BF assessed by bioelectrical impedance analysis (BIA) stratified by sex, SOLNAS HCHS/SOL Ancillary Study (n = 471). Dotted line represents perfect agreement between measurements; gray areas around sex-specific regression lines correspond to 95% prediction limits.

Figure 3

Non-linear relationship between the corrected percentage of body fat (%BF) corrected by the 18O dilution method and body mass index (BMI) among the Hispanic/Latino women (A) and men (B) and the linear relationship between the %BF corrected by the 18O dilution method and 1/BMI among the Hispanic/Latino women (C) and men (D). Points represent 1000 randomly selected participants and solid lines portray weighted smoothing fit for all participants.