Asymptomatic Achilles tendon pathology is associated with a central fat distribution in men and a peripheral fat distribution in women: a cross sectional study of 298 individuals

Abstract

Background: Adiposity is a modifiable factor that has been implicated in tendinopathy. As tendon pain reduces physical activity levels and can lead to weight gain, associations between tendon pathology and adiposity must be studied in individuals without tendon pain. Therefore, the purpose of this study was to determine whether fat distribution was associated with asymptomatic Achilles tendon pathology.

Methods: The Achilles tendons of 298 individuals were categorised as normal or pathological using diagnostic ultrasound. Fat distribution was determined using anthropometry (waist circumference, waist hip ratio [WHR]) and dual-energy x-ray absorptiometry.

Results: Asymptomatic Achilles tendon pathology was more evident in men (13%) than women (5%) (p = 0.007). Men with tendon pathology were older (50.9 +/- 10.4, 36.3 +/- 11.3, p < 0.001), had greater WHR (0.926 +/- 0.091, 0.875 +/- 0.065, p = 0.039), higher android/gynoid fat mass ratio (0.616 +/- 0.186, 0.519 +/- 0.142, p = 0.014) and higher upper-body/lower body fat mass ratio (2.346 +/- 0.630, 2.022 +/- 0.467, p = 0.013). Men older than 40 years with a waist circumference >83 cm had the greatest prevalence of tendon pathology (33%). Women with tendon pathology were older (47.4 +/- 10.0, 36.0 +/- 10.3, p = 0.008), had less total fat (17196 +/- 3173 g, 21626 +/- 7882 g, p = 0.009), trunk fat (7367 +/- 1662 g, 10087 +/- 4152 g, p = 0.003) and android fat (1117 +/- 324 g, 1616 +/- 811 g, p = 0.005). They had lower central/peripheral fat mass ratios (0.711 +/- 0.321 g, 0.922 +/- 0.194 g, p = 0.004) than women with normal tendons. Women with tendon pathology were more often menopausal (63%, 13%, p = 0.002).

Conclusions: Men with Achilles tendon pathology were older and had a central fat distribution. Women with tendon pathology were older and had a peripheral fat distribution. An interaction between age and waist circumference was observed among men.

Figure 1

Typical full body DXA scan. The android region of interest (ROI) is highlighted in blue and the gynoid ROI is highlighted in red (refer to text for the landmarks that define these regions).

Figure 2

Scatter-plot of age and waist circumference in men. Men with normal tendons are indicated by blue triangles while men with asymptomatic Achilles tendon pathology are indicated by green squares.

Figure 3

Scatter-plot of age and waist circumference in women. Women with normal tendons are indicated by blue triangles while women with asymptomatic Achilles tendon pathology are indicated by green squares.