Abdominal obesity is associated with heart disease in dogs

Abstract

Background: The relationship between overall obesity and fat distribution in dogs and the development of heart disease is unclear. In the present study we evaluated the association between overall obesity and fat distribution and clinical heart disease by morphometric and computed tomography (CT)-based measurements. Body condition score (BCS), modified body mass index (MBMI, kg/m2), waist-to-hock-to-stifle distance ratio (WHSDR), waist-to-ilium wing distance ratio (WIWDR), and waist-to-truncal length ratio (WTLR) were compared between dogs with (n = 44) and without (n = 43) heart disease using receiver operating characteristic (ROC) analysis. Intra-abdominal fat (IAF) and subcutaneous fat (SQF) were measured in dogs with (n = 8) and without (n = 9) heart disease at the center of the fourth and fifth lumbar vertebrae by CT.

Results: BCS was similar between heart disease and healthy groups (3.6 ± 0.2 vs. 3.3 ± 0.1, P = 0.126). The following morphometric measurements were greater in the heart disease group compared with healthy canines: MBMI (65.0 ± 4.5 vs. 52.5 ± 3.7 kg/m2, respectively, P = 0.035); WIWDR (4.1 ± 0.1 vs. 3.1 ± 0.1, P < 0.01); and WTLR (1.25 ± 0.04 vs. 1.05 ± 0.04, P < 0.01). However, there was no significant difference in WHSDR (3.6 ± 0.1 vs. 3.7 ± 0.2, P = 0.875). Interestingly, IAF was significantly increased in dogs with heart disease compared with healthy dogs (23.5 ± 1.5% vs. 19.4 ± 1.2%, P = 0.039) whereas SQF was similar between two groups (35.5 ± 2.7% vs. 38.6 ± 3.5%, P = 0.496). Of the five morphometric indices studied, WIWDR and WTLR provided acceptable discrimination for diagnosing heart disease in dogs, with areas under the ROC curve of 0.778 (95% confidence interval [CI]:0.683-0.874) and 0.727 (95% CI:0.619-0.835), respectively.

Conclusions: Our data indicate that abdominal obesity, rather than overall obesity, is associated with heart disease in dogs. Measurements of both WIWDR and WTLR are particular useful for detection of an abdominal obesity in dogs.

Figure 1

Average body condition score (mean ± SE) of male and female dogs from healthy and heart disease groups.

Figure 2

The cross-sectional area (mean ± SE) of abdominal fat using computed tomography at the fourth and fifth lumbar vertebrae. The area of intra-abdominal fat (IAF) and subcutaneous fat (SQF) was compared between healthy dogs (A) and dogs with heart disease (B). The subcutaneous fat was identified inside the black dashed line and outside the red dashed line. The area of intra-abdominal fat was identified inside the red dashed line.

Figure 3

The percentage of cross-sectional areas of subcutaneous and intra-abdominal fat between healthy dogs and dogs with heart disease. *P < 0.05.