ABSTRACT
OBJECTIVE: To examine whether aging itself affects insulin resistance (IR) and insulin secretion in the general Japanese population. METHODS: This study included data for 2,324 men and 1,472 women 30-79 years of age without diabetes who participated in a general health checkup program. The effects of age on homeostasis model assessment of insulin resistance (HOMA-IR) and homeostasis model assessment of ß-cell function (HOMA-B) were examined using a linear regression model. Logistic regression models were used to identify clinical characteristics related to age. Multiple regression analyses using a stepwise form were performed to examine factors, including age, possibly affecting HOMA-IR and HOMA-B. RESULTS: The fasting plasma glucose (FPG) levels increased with age in both sexes, whereas the body mass index (BMI) and HOMA-B decreased with increasing age in men and the BMI increased with age in women. The HOMA-IR increased with increasing age in postmenopausal women. The proportion of physically active subjects increased in both sexes, and the proportion of current smokers decreased with age in men and postmenopausal women. The proportion of regular drinkers increased, and the proportion of subjects with a family history of diabetes decreased with age in men. The stepwise multiple regression analysis showed that age was inversely associated with the HOMA-B in both sexes and positively associated with the HOMA-IR in men and postmenopausal women. However, the BMI had the largest impact on the HOMA-IR and HOMA-B in both sexes. CONCLUSION: Age-related increases in the glucose levels in Japanese men and women may be associated with impaired insulin secretion. As a result, a sex difference was observed regarding the impact of aging on IR.
Subject(s)
Aging , Diabetes Mellitus/epidemiology , Insulin Resistance/physiology , Insulin/blood , Adult , Age Factors , Aged , Body Mass Index , Diabetes Mellitus/blood , Female , Humans , Incidence , Japan/epidemiology , Male , Middle Aged , Retrospective Studies , Risk FactorsABSTRACT
To determine the association between both age and degree of albuminuria and pulse pressure in patients with type 2 diabetes, we conducted this study consisting of two cross-sectional observations. A total of 833 ambulatory and 107 hospitalized type 2 diabetic patients with serum creatinine <2.00 mg/dl were studied. Systolic blood pressure (SBP), diastolic blood pressure (DBP), and pulse pressure (PP) were compared among ambulatory patients stratified according to the degree of albuminuria, as well as according to age at 10-year intervals. In the hospitalized patients, 24-h blood pressure was monitored, and 24-h SBP, DBP, and PP were correlated with aortic pulse wave velocity (PWV) and mean intima-media thickness (IMT) of the carotid arteries. In the ambulatory patients, SBP and PP were greater in patients with microalbuminuria and clinical albuminuria, as well as in the older groups, whereas DBP tended to be lower in the older age groups. Multiple regression analysis adjusted for covariates including age indicated that increased albuminuria was independently associated with greater PP (p < 0.001). In the hospitalized patients, stepwise increases were observed in SBP and PP (daytime, nighttime and overall 24-h), but not in DBP, in microalbuminuric and albuminuric patients. SBP and PP were positively and DBP was negatively associated with aortic PWV; however, no association was found with IMT. In conclusion, PP is closely associated with higher age, degree of albuminuria, and large artery stiffness in patients with type 2 diabetes.
Subject(s)
Albuminuria/physiopathology , Blood Pressure/physiology , Diabetes Mellitus, Type 2/physiopathology , Kidney Diseases/physiopathology , Adult , Age Factors , Aged , Carotid Arteries/pathology , Carotid Arteries/physiopathology , Chronic Disease , Cross-Sectional Studies , Elasticity , Female , Glomerular Filtration Rate/physiology , Humans , Hypertension/physiopathology , Male , Middle Aged , Regression Analysis , Severity of Illness IndexABSTRACT
To investigate the association of oxidized low-density lipoprotein (ox-LDL) with the development of diabetic nephropathy, plasma levels of ox-LDL were measured in 70 patients with type 2 diabetes mellitus. A sandwich enzyme-linked immunoadsorbent assay (ELISA) using the mouse monoclonal antibody FOH1a/DLH3, which specifically recognizes oxidized phosphatidylcholine, and a horseradish peroxidase (HRP)-labeled goat anti-human apolipoprotein B IgG was used to measure ox-LDL levels. The mean age of the patients was 57.0+/-1 3.4 years, and the mean duration of diabetes was 13.4+/-8.5 years. Plasma ox-LDL levels were similar in patients with normoalbuminuria (13.7+/-3.9 U/ml), patients with microalbuminuria (12.8+/-3.9 U/ml), and normal controls (12.5+/-4.2 U/ml). However, the plasma ox-LDL level in patients with macroalbuminuria (16.8+/-7.5 U/ml) was significantly higher than those in the other groups (P<0.05). Hemoglobin A1c (HbA1c) levels were similar in diabetic patients with normoalbuminuria (8.2+/-2.2%), microalbuminuria (7.8+/-1.3%), or macroalbuminuria (7.2+/-1.4%). There was no significant correlation between the ox-LDL level and the HbA1c level. The significantly elevated plasma ox-LDL levels in patients with macroalbuminuria suggest that ox-LDL may play an important role in the progression of diabetic nephropathy.
