Weight loss surgery outcomes may be influenced by Inflammation, shows study

Higher levels of inflammation in the blood of patients with obesity undergoing bariatric surgery predict poorer weight loss six months after the procedure, according to a recent study by researchers from IoPPN, King’s College London. The analysis showed a strong relationship between depression and inflammation in obese patients before and after surgery and it indicated that it was increased inflammation, rather than depression that was driving poor weight loss after bariatric surgery.

The 85 participants in the study, were all obese (BMI >35) and part of the ongoing Bariatric Surgery & Depression study. Levels of proteins released during inflammation, such as C-reactive protein (CRP), and cytokines, such as interleukin-6 (IL-6) and interleukin-4 (IL-4), were measured before and after surgery in participants’ blood and tissue.

The study showed that those with depression had higher levels of the inflammatory proteins CRP and IL-6 in the blood and lower levels of the anti-inflammatory protein IL-4. They also had higher levels of one inflammatory protein in their adipose tissue.

Six months after surgery, the bariatric patients who had depression before surgery continued to have higher levels of IL-6 and CRP in the blood, despite no difference in weight loss between those with and without depression.

Overall bariatric surgery led to weight loss in all patients in line with what is expected, and the majority of patients who previously had depression before surgery also experienced a reduction in their symptoms so that they were no longer considered clinically depressed.

Reference: ‘Peripheral inflammation associated with depression and reduced weight loss: a longitudinal study of bariatric patients’ by McLaughlin, A. P et al was published in Psychological Medicine. DOI: 10.1017/S0033291723002283