(HealthDay News) – Lower-extremity lymphedema may be due to extreme obesity, as there appears to be a body mass index (BMI) threshold above which lymphatic flow becomes impaired.

Arin K. Greene, MD, from the Children’s Hospital Boston, and colleagues reviewed data from 15 obese patients with bilateral lower-extremity enlargement, to identify the role of obesity in lymphedema. The patients underwent lymphoscintigraphy, reported to be 100% specific and 92% sensitive for lymphedema.

The researchers identified abnormal results for five patients on lymphoscintigraphy; the results showed impaired lymphatic function consistent with lymphedema. The patients with lymphedema had a significantly greater average BMI than those without lymphedema (70.1 vs. 42kg/m²). All patients with a BMI >59kg/m² had lymphedema, while lymphatic function was normal for all those with a BMI <54kg/m².

“Our findings suggest that obesity, which affects one-third of the population in the United States, may be a cause of lower-extremity lymphedema. As BMI increases, there might be a threshold above which lymphatic flow becomes impaired,” the authors write. “Although lymphedema is typically progressive, we speculate that major weight loss (eg, after a bariatric procedure) might reverse lymphatic insufficiency in obese patients with this condition.”

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