In the Journals

PCB levels rise in women with obesity after weight loss

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October 20, 2015

Women with obesity assigned to lose weight through diet or bariatric surgery saw a rise in serum polychlorinated biphenyl levels at 6 months, with a greater effect observed in women who lost weight through diet, according to research in The Journal of Clinical Endocrinology & Metabolism.

Eveline Dirinck, MD, of the departments of endocrinology, diabetology and metabolic disease at Antwerp University Hospital in Edegem, Belgium, and colleagues analyzed data from 45 women with obesity (mean age, 40 years; mean BMI, 40 kg/m²) who visited the weight management clinic at Antwerp University Hospital between 2010 and 2012. Within the cohort, 20 women received dietary counseling and exercise instruction; 25 women underwent bariatric surgery. The women in the surgery group received nutrition advice after surgery. At baseline and 6 months of follow-up, researchers measured BMI, waist circumference and body composition; participants underwent a CT scan to measure total abdominal adipose tissue, visceral abdominal tissue and subcutaneous abdominal tissue. Researchers analyzed blood samples for polychlorinated biphenyl (PCB) levels at baseline and at 6-month follow-up.

After 6 months, all but one patient had lost weight; 16 women (four in the surgery group) experienced weight loss of 10% or less; 29 women (21 in the surgery group) lost more than 10% body weight. Serum PCB levels in all women who lost weight rose by a mean of 47% at 6 months.

In correlation and regression analysis, researchers also found that the rise in serum PCB levels was more pronounced in women who lost more visceral adipose tissue during weight loss. A subanalysis of the diet and surgery groups showed that the trend could be established in the diet group, but not in the surgery group, according to researchers.

“Analysis of sequential CT measurements of the abdominal subcutaneous and visceral fat compartment suggests that the visceral fat compartment in particular might play a dominant role in the release of PCBs during weight loss,” the researchers wrote. “These findings are mainly present after weight loss induced by dietary measures, but could not be established in the subgroup with surgically induced weight loss.”

Researchers noted that the findings might help explain the “obesity paradox.”

“Recently, it has been suggested that this obesity paradox is only present in an obese population with low levels of [persistent organic pollutants],” the researchers wrote. “It is conceivable that weight cycling, with repetitive release of large amounts of [persistent organic pollutants] from the fat compartment and subsequent reabsorption in a re-expanding fat mass, might cause endocrine-disrupting effects on metabolic and cardiovascular function.” – by Regina Schaffer

Disclosure: The researchers report no relevant financial disclosures.