Longitudinal changes in pancreatic volume and pancreatic fat with weight gain in Japanese without diabetes: An analysis using health check-up data

AIMS/INTRODUCTION: There have been few reports about the longitudinal changes in pancreas volume (PV) or pancreatic steatosis (PS) in response to obesity. In this longitudinal analysis using health check-up data, we explored changes in PV, PS and glucose metabolic indices that occurred after weight gain in Japanese without diabetes. MATERIALS/METHODS: Clinical data on 37 Japanese subjects with a ≥1 kg/m(2) increase in body mass index between two health check-ups and without diabetes were collected. PV, pancreas attenuation (PA) and splenic attenuation (SA) were evaluated using computed tomography (CT) images. The pancreas area was outlined by hand in multiple images with slice thickness of 2 mm, and the PV was computed by summing these areas. PS was defined as the difference between SA and PA (SA-PA). Medical records were collected, including findings on immunoreactive insulin (IRI), homeostasis model assessment of insulin resistance (HOMA-R) and beta cell function (HOMA-β). Paired t-test and Spearman's correlation coefficient were used in the analyses. RESULTS: The median follow-up period was 21.1 months and the mean BMI was increased from 25.5 ± 3.3 kg/m(2) to 27.0 ± 3.3 kg/m(2). PV (53.5 ± 15.9 cm(3) vs. 56.2 ± 16.4 cm(3)) and SA-PA (8.7 ± 9.1 HU vs. 13.6 ± 10.9 HU) increased significantly after weight gain (both, P < 0.001). There were significant increases of IRI and HOMA-R with the weight gain (both, P < 0.05), whereas HOMA-β exhibited only a nonsignificant trend of increase (55.4％ (41.5-65.5) vs. 56.8％ (46.2-83.7), P = 0.07). CONCLUSIONS: Both PV and PS were increased longitudinally with weight gain in Japanese without diabetes.