Endocrine Abstracts

Introduction: The neurohormones A and B-type natriuretic peptides are markedly increased in patients with heart disease, and are well established as useful diagnostic biomarkers. Obesity is a known risk factor for cardiovascular disease. Cross sectional data suggest however that plasma levels are reduced among obese. Therefore, the aim of the present study was to investigate the impact of weight loss and corresponding changes in body composition on plasma levels of A and B-type natriuretic peptides.

Methods and design: Fifty-two obese individuals 47 women, BMI 36.5±5.6 kg/m²; age 62±7 years (mean±S.D.). Randomized to either intervention on a weight reduction program, using a low energy diet between 3.4 and 5 MJ/day, or to a control group which was offered diet counseling. Body composition measuring fat and fat free mass using whole body Dual energy X-ray (DEXA) scan, and plasma levels of NT-proBNP, MR-proANP and were measured at baseline and after 52 weeks.

Results: In the intervention group (n=28), diet induced a substantial weight loss (BMI 31.6±6.2 vs. 37.1±6.1 kg/m²; P<0.001) and loss in body fat (23.5±15.5%; P<0.001) after 52 weeks. Corresponding, plasma NT-proBNP (97±55 vs. 55±31 pg/ml; P< 0.001) and MR-proANP (74±26 vs. 59±21 pmol/l; P< 0.001) levels increased. A modest weight loss (33.6±5.5 vs. 35.8±5.5 kg/m²; P=0.001), and body fat (9.2±11.0%; P<0.05) was observed among controls (n=24), with no changes in NT-proBNP or MR-proANP concentrations. The loss in total weight and in fat mass were significantly higher in the intervention as compared with the control group (P<0.001), for both.

Conclusions: NT-proBNP and MR-proANP concentrations increases in circulating plasma during substantial weight loss, underlining the impact of BMI on plasma levels of A and B-type natriuretic peptides.