Improved metabolism and body composition beyond normal levels following gastric bypass surgery: a longitudinal study

• Published in: Journal of internal medicine Vol. 285; no. 1; pp. 92 - 101
• Main Authors: Andersson, D. P., Dahlman, I., Eriksson Hogling, D., Bäckdahl, J., Toft, E., Qvisth, V., Näslund, E., Thorell, A., Rydén, M., Arner, P.
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.01.2019
• Subjects: Adipocytes; Adipose tissue; Benign; Blood pressure; Body composition; Body fat; Body mass; cardiovascular disease risk factors; Cell size; Cholesterol; Complications; Control methods; Correlation analysis; Gastric bypass; Gastrointestinal surgery; Health risks; High density lipoprotein; Hyperplasia; Inflammation; Insulin; Insulin resistance; Lipids; Longitudinal studies; Low density lipoprotein; Medicin och hälsovetenskap; Metabolism; Morphology; obesity; Risk assessment; Sensitivity; Sensitivity analysis; Surgery; Weight; weight loss; adipose tissue; weight loss; body composition; cardiovascular disease risk factors; insulin resistance; obesity
• ISSN: 0954-6820; 1365-2796; 1365-2796
• DOI: 10.1111/joim.12824

Background The cardiometabolic risk profile improves following bariatric surgery. However, the degree of improvement in relation to weight‐stable control subjects is unknown. Objectives To study the differences in cardiometabolic risk profile between formerly obese patients following Roux‐en‐Y gastric bypass (RYGB) surgery and control subjects. Methods Subjects undergoing RYGB and reaching a BMI <30 kg m−2 2 years postsurgery were matched with control subjects regarding age, sex and BMI. The following examinations were performed: insulin sensitivity measured by hyperinsulinaemic–euglycaemic clamp, insulin clearance, homeostatic model assessment of insulin resistance (HOMA‐IR), lipid profile, inflammatory marker levels, dual‐energy X‐ray absorptiometry and subcutaneous adipose tissue cellularity (fat cell size and number). Results Sixty‐nine subjects undergoing RYGB were matched to a control subject. Insulin sensitivity measured by hyperinsulinaemic–euglycaemic clamp, blood pressure, inflammatory status and glucose, triglyceride and HDL cholesterol levels were comparable to values of control subjects. However, HOMA‐IR (1.0 ± 0.5 vs. 1.3 ± 0.7, P = 0.005), insulin clearance (0.38 ± 0.08 vs. 0.34 ± 0.08 μL m−2 min−1, P < 0.0001) and circulating levels of insulin (31 ± 15 vs. 37 ± 17 pmol L−1, P = 0.008), total cholesterol (4.1 ± 0.7 vs. 4.8 ± 0.9 mmol L−1, P < 0.0001) and LDL cholesterol (2.1 ± 0.6 vs. 2.9 ± 0.8 mmol L−1, P < 0.0001) were improved beyond the levels in matched control subjects. Furthermore, formerly obese subjects had higher lean and lower fat mass as well as a more benign type of adipose cellularity (hyperplasia with many small fat cells) compared to control subjects. Conclusions Subjects who underwent RYGB and reached a postobese state demonstrated a beneficial body composition, slightly increased insulin sensitivity as indirectly measured by HOMA‐IR and higher insulin clearance, lower atherogenic lipid/lipoprotein levels and benign adipocyte morphology compared with control subjects who had never been obese. In line with previous results, our findings may in part explain why RYGB confers long‐term protection against metabolic complications.