Obesity places children at higher risk of blood clots, say researchers
Researchers were able to identify obesity as a statistically significant predictor of blood clot formation in juveniles. Obesity is well known as a risk factor for venous thromboembolism (VTE) in adults but in paediatrics previous results had struggled to find a link.
Led by Dr Elizabeth Halvorson, assistant professor of paediatrics at Wake Forest Baptist's Brenner Children’s Hospital, the researchers found a small but statistically significant association between obesity and VTE, which can cause both acute and chronic health problems if left untreated, according to data published in the current issue of the journal Hospital Pediatrics.
"This is important because the incidence of paediatric VTE has increased dramatically over the last 20 years and childhood obesity remains highly prevalent in the United States," said Halvorson.
A similar study in 2014 was able to establish a correlation between obesity and VTE in a group of hospitalised children, who presented a risk for VTE in obese children similar to the one described in much larger adult cohorts.
It is not known whether obesity facilitates risk through shared mechanisms. Although the association between obesity and VTE appears to be moderate, obesity can interact with other environmental or genetic factors and pose a significantly greater risk of VTE among obese individuals.
For the study the researchers conducted a review of inpatients at the hospital between January 2000 and September 2012. They identified patients ages 2 to 18 who had confirmed cases of VTE. Of these, 33 (37%) were obese, though most of them had known risk factors for blood clots in addition to obesity.
Control subjects were matched on age, gender, and the presence of a central venous catheter. Data were also collected on weight, height, and risk factors. Underweight patients and those without documented height and weight data were excluded.
The researchers identified 88 patients. The majority of cases were nonembolic events (77%) of the lower extremity (25%) or head and neck (22%) confirmed by ultrasound (43%) or computed tomography scan (41%). A statistically significant association was found between VTE and increased BMI of the patients.
“Our study presents data from a single institution with a relatively small sample size,” Halvorson said. “But it does demonstrate an association between obesity and VTE in children, which should be explored further in larger future studies.”
Childhood obesity is a major health problem in Western Europe and the United States. Of particular concern are the risks that millions of obese people are likely to develop chronic diseases and at earlier ages than their parents might have. One review calculated the risk appeared to be at least double that for normal weight subjects (BMI 20 to 24.9 kg/m2).
Credible mechanisms exist to explain this relationship, including the physical effects of body fat limiting venous return and an environment that induces inflammation and thrombosis. Loss of body weight has been shown to reduce the concentrations of coagulation factors and plasminogen activator inhibitor-1 toward the normal range.
Source: Hospital Pediatrics
First published online Jan 2016, 6 (1), pp. 22-26, DOI: 10.1542/hpeds.2015-0039
“Association of Obesity and Pediatric Venous Thromboembolism”
Authors: Elizabeth E. Halvorson, Sean E. Ervin, Thomas B. Russell, Joseph A. Skelton, Stephen Davis, John Spangler
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