Diabetes Center, Shin-Suma Hospital, Kobe, Japan.
Division of Diabetes, Metabolism and Endocrinology, Department of Internal Medicine, Toho University Graduate School of Medicine, Tokyo, Japan.
Geriatr Gerontol Int. 2018 Jul;18(7):1046-1050. doi: 10.1111/ggi.13303. Epub 2018 Apr 17.
The present study was carried out to examine whether the insulin secretory mechanism deteriorates during the aging process using the new intact proinsulin assay system in non-diabetic and diabetic individuals.
A total of 172 participants were separated into four groups according to their age (<64 years and >65 years) and an association of type 2 diabetes; that is, 46 older diabetics (mean age 74.5 ± 6.2 years, glycated hemoglobin [National Glycohemoglobin Standardization Program] 7.5 ± 1.3%), 27 older non-diabetics (mean age 76.9 ± 7.5 years), 48 middle-aged diabetics (mean age 50.8 ± 10.4, glycated hemoglobin 7.8 ± 1.5%) and 51 middle aged non-diabetics (mean age 46.6 ± 13.0 years) participants were enrolled.
The proinsulin/insulin (PI/I) ratio of the diabetic group was higher than that of the non-diabetic group in the older group (0.19 ± 0.12 vs 0.11 ± 0.06, P = 0.002). In the middle-aged groups, the PI/I ratio of the diabetic group was higher than that of the non-diabetic group (0.16 ± 0.15 vs 0.09 ± 0.09, P = 0.003). Simple regression analysis showed that male sex (95% CI 0.02-0.01, P = 0.004), age (95% CI 0.00-0.002, P = 0.03), lower body mass index (95% CI -0.06 to 0.00, P = 0.02) and the presence of diabetes mellitus (95% CI 0.04-0.012, P < 0.0001) were significantly associated with the increase in the PI/I ratio. Multivariate regression analysis showed that male sex and age were the independent factors determining the increase in the PI/I ratio in the non-diabetic group. After adjusted for body mass index, the PI/I ratio correlated significantly with age only in the non-diabetic group (r = 0.5, P = 0.004).
The proinsulin processing system might deteriorate not only in diabetics, but also in non-diabetic Japanese individuals with age. Also, sex-related hormones can be protective for the proinsulin processing system. Geriatr Gerontol Int 2018; 18: 1046-1050.
本研究旨在使用新的完整胰岛素原检测系统，在非糖尿病和糖尿病个体中，研究胰岛素分泌机制是否随年龄增长而恶化。
根据年龄（<64 岁和>65 岁）和 2 型糖尿病的相关性，将 172 名参与者分为四组；即 46 名老年糖尿病患者（平均年龄 74.5±6.2 岁，糖化血红蛋白[全国糖化血红蛋白标准化计划]7.5±1.3%）、27 名老年非糖尿病患者（平均年龄 76.9±7.5 岁）、48 名中年糖尿病患者（平均年龄 50.8±10.4 岁，糖化血红蛋白 7.8±1.5%）和 51 名中年非糖尿病患者（平均年龄 46.6±13.0 岁）。
老年组中，糖尿病组的胰岛素原/胰岛素（PI/I）比值高于非糖尿病组（0.19±0.12 比 0.11±0.06，P=0.002）。在中年组中，糖尿病组的 PI/I 比值高于非糖尿病组（0.16±0.15 比 0.09±0.09，P=0.003）。简单回归分析显示，男性（95%可信区间 0.02-0.01，P=0.004）、年龄（95%可信区间 0.00-0.002，P=0.03）、较低的体重指数（95%可信区间-0.06 至 0.00，P=0.02）和糖尿病（95%可信区间 0.04-0.012，P<0.0001）与 PI/I 比值升高显著相关。多元回归分析显示，男性和年龄是非糖尿病组 PI/I 比值升高的独立因素。调整体重指数后，非糖尿病组 PI/I 比值与年龄呈显著正相关（r=0.5，P=0.004）。
胰岛素原加工系统不仅在糖尿病患者中恶化，而且在日本非糖尿病的老年个体中也恶化。此外，与性别相关的激素可能对胰岛素原加工系统有保护作用。老年医学与老年病学杂志 2018；18：1046-1050。
