BMI linked to risk for orthostatic intolerance post bariatric Sx

(HealthDay)—Lower body mass index (BMI) and body fat is associated with increased risk of orthostatic intolerance (OI) and predisposition to noncardiac syncope (NCS) following bariatric surgery, according to research published online Jan. 23 in Obesity Reviews.

Georgios A. Christou, M.D., Ph.D., and Dimitrios N. Kiortsis, M.D., Ph.D., from the University of Ioannina in Greece, and colleagues examined the effects of body weight status on OI and predisposition to NCS.

The researchers found that most cross-sectional studies have shown that the lower the BMI, the greater the predisposition to OI; this was accompanied by down-regulation of sympathetic nervous system activity and up-regulation of activity of the parasympathetic nervous system. These changes were seen across the spectrum of BMI values, and may be associated with central body fat more strongly than total body fat. Increased OI was seen in association with weight loss following bariatric surgery, which was attributed to the effects of weight loss, the specific type of surgical procedure, and the potential postoperative autonomic neuropathy due to vitamin deficiency. For affected individuals, the increased OI rendered bariatric surgery not easily tolerable, with increased fluid and salt intake, pharmacological measures, or surgical adjustments necessary to attenuate OI.

"The relationship between orthostatic responses and body weight status has important implications in the evaluation of the results of studies investigating orthostatic responses and NCS," the authors write.