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Cardiorespiratory fitness and mitochondrial oxidative capacity are associated with reduced walking speed in older adults, but their impact on walking speed in older adults with diabetes has not been clearly defined. We examined differences in cardiorespiratory fitness and skeletal muscle mitochondrial oxidative capacity between older adults with and without diabetes, as well as determined their relative contribution to slower walking speed in older adults with diabetes. Participants with diabetes (n = 159) had lower cardiorespiratory fitness and mitochondrial respiration in permeabilized fiber bundles compared with those without diabetes (n = 717), following adjustments for covariates including BMI, chronic comorbid health conditions, and physical activity. Four-meter and 400-m walking speeds were slower in those with diabetes. Mitochondrial oxidative capacity alone or combined with cardiorespiratory fitness mediated ∼20–70% of the difference in walking speed between older adults with and without diabetes. Additional adjustments for BMI and comorbidities further explained the group differences in walking speed. Cardiorespiratory fitness and skeletal muscle mitochondrial oxidative capacity contribute to slower walking speeds in older adults with diabetes. Article Highlights: The contributors to slower walking speed in older adults with diabetes remain unclear. This study was conducted to answer the question of how mitochondrial oxidative capacity and cardiorespiratory fitness impact walking speed in older adults with diabetes. We found that mitochondrial oxidative capacity, cardiorespiratory fitness, and walking speed were lower in older adults with diabetes compared with those without diabetes. In addition, mitochondrial oxidative capacity and cardiorespiratory fitness contributed to slower walking speed in those with diabetes. [ABSTRACT FROM AUTHOR]

Objective: Previous studies demonstrate that the metabolic syndrome is associated with distal symmetric polyneuropathy (DSP). We aimed to determine the magnitude of this effect and the precise components involved.Research Design and Methods: We determined the symptomatic DSP prevalence in the Health, Aging, and Body Composition (Health ABC) study (prospective cohort study, with subjects aged 70-79 years at baseline), stratified by glycemic status (glucose tolerance test) and the number of additional metabolic syndrome components (updated National Cholesterol Education Program/Adult Treatment Panel III definition). DSP was defined as neuropathic symptoms (questionnaire) plus at least one of three confirmatory tests (heavy monofilament, peroneal conduction velocity, and vibration threshold). Multivariable logistic and linear regression evaluated the association of metabolic syndrome components with DSP in cross-sectional and longitudinal analyses.Results: Of 2,382 participants with neuropathy measures (mean age 73.5 ± 2.9 years, 38.2% black, 51.7% women), 21.0% had diabetes, 29.9% prediabetes, 52.8% metabolic syndrome, and 11.1% DSP. Stratified by glycemic status, DSP prevalence increased as the number of metabolic syndrome components increased (P = 0.03). Diabetes (cross-sectional model, odds ratio [OR] 1.65 [95% CI 1.18-2.31]) and baseline hemoglobin A1C (longitudinal model, OR 1.42 [95% CI 1.15-1.75]) were the only metabolic syndrome measures significantly associated with DSP. Waist circumference and HDL were significantly associated with multiple secondary neuropathy outcomes.Conclusions: Independent of glycemic status, symptomatic DSP is more common in those with additional metabolic syndrome components. However, the issue of which metabolic syndrome components drive this association, in addition to hyperglycemia, remains unclear. Larger waist circumference and low HDL may be associated with DSP, but larger studies with more precise metabolic measures are needed. [ABSTRACT FROM AUTHOR]

OBJECTIVE -- A loss of skeletal muscle mass is frequently observed in older adults. The aim of the study was to investigate the impact of type 2 diabetes on the changes in body composition, with particular interest in the skeletal muscle mass. RESEARCH DESIGN AND METHODS -- We examined total body composition with dual-energy X-ray absorptiometry annually for 6 years in 2,675 older adults. We also measured mid-thigh muscle cross-sectional area (CSA) with computed tomography in year 1 and year 6. At baseline, 75-g oral glucose challenge tests were performed. Diagnosed diabetes (n = 402, 15.0%) was identified by self-report or use of hypoglycemic agents. Undiagnosed diabetes (n = 226, 8.4%) was defined by fasting plasma glucose (≥7 mmol/l) or 2-h postchallenge plasma glucose (≥ 11.1 mmol/l). Longitudinal regression models were fit to examine the effect of diabetes on the changes in body composition variables. RESULTS-- Older adults with either diagnosed or undiagnosed type 2 diabetes showed excessive loss of appendicular lean mass and trunk fat mass compared with nondiabetic subjects. Thigh muscle CSA declined two times faster in older women with diabetes than their nondiabetic counterparts. These findings remained significant after adjusting for age, sex, race, clinic site, baseline BMI, weight change intention, and actual weight changes over time. CONCLUSIONS -- Type 2 diabetes is associated with excessive loss of skeletal muscle and trunk fat mass in community-dwelling older adults. Older women with type 2 diabetes are at especially high risk for loss of skeletal muscle mass. [ABSTRACT FROM AUTHOR]

OBJECTIVE -- Poor peripheral nerve function is prevalent in diabetes and older populations, and it has great potential to contribute to poor physical performance. RESEARCH DESIGN AND METHODS-- Cross-sectional analyses were done for the Health, Aging, and Body Composition (Health ABC) Study participants (n = 2,364; 48% men; 38% black; aged 73-82 years). Sensory and motor peripheral nerve function in legs/feet was assessed by 10- and 1.4-g monofilament perception, vibration detection, and peroneal motor nerve conduction amplitude and velocity. The Health ABC lower-extremity performance battery was a supplemented version of the Established Populations for the Epidemiologic Studies of the Elderly battery (chair stands, standing balance, and 6-m walk), adding increased stand duration, single foot stand, and narrow walk. RESULTS -- Diabetic participants had fewer chair stands (0.34 vs. 0.36 stands/s), shorter standing balance time (0.69 vs. 0.75 ratio), slower usual walking speed (1.11 vs. 1.14 m/s), slower narrow walking speed (0.80 vs. 0.90 m/s), and lower performance battery score (6.43 vs. 6.93) (all P < 0.05). Peripheral nerve function was associated with each physical performance measure independently. After addition of peripheral nerve function in fully adjusted models, diabetes remained significantly related to a lower performance battery score and slower narrow walking speed but not to chair stands, standing balance, or usual walking speed. CONCLUSIONS -- Poor peripheral nerve function accounts for a portion of worse physical performance in diabetes and may be directly associated with physical performance in older diabetic and nondiabetic adults. The impact of peripheral nerve function on incident disability should be evaluated in older adults. [ABSTRACT FROM AUTHOR]

OBJECTIVE -- It has been shown that adults with either long-standing type 1 or type 2 diabetes had lower skeletal muscle strength than nondiabetic adults in cross-sectional studies. The aim of the study was to investigate longitudinal changes of muscle mass and strength in community-dwelling older adults with and without type 2 diabetes. RESEARCH DESIGN AND METHODS -- We examined leg and arm muscle mass and strength at baseline and 3 years later in 1,840 older adults aged 70-79 years in the Health, Aging, and Body Composition Study. Regional muscle mass was measured by dual energy X-ray absorptiometry, and muscle strength was measured using isokinetic and isometric dynamometers. RESULTS -- Older adults with type 2 diabetes (n = 305) showed greater declines in the leg muscle mass (-0.29 ± 0.03 vs. -0.23 ± 0.01 kg, P < 0.05) and strength (-16.5 ± 1.2 vs. -12.4 ± 0.5 Nm, P = 0.001) compared with older adults without diabetes. Leg muscle quality, expressed as maximal strength per unit of muscle mass (Newton meters per kilogram), also declined more rapidly in older adults with diabetes (-1.6 ± 0.2 vs. -1.2 ± 0.1 Nm/kg, P < 0.05). Changes in arm muscle strength and quality were not different between those with and without diabetes. Rapid declines in leg muscle strength and quality were attenuated but remained significant after controlling for demographics, body composition, physical activity, combined chronic diseases, interleukin-6, and tumor necrosis factor-α. CONCLUSIONS -- In older adults, type 2 diabetes is associated with accelerated loss of leg muscle strength and quality. [ABSTRACT FROM AUTHOR]

OBJECTIVE -- Age, diabetes, and elevated inflammatory markers independently increase the risk of functional decline. We examined the effect of C-reactive protein (CRP) and interleukin-6 (IL-6) on the incident mobility limitation in older adults with and without diabetes. RESEARCH DESIGN AND METHODS -- We analyzed data from a cohort of 2,895 well-functioning adults aged 70-79 years, followed for development of persistent functional limitation over 3.5 years. Participants were assessed for the presence of diabetes according to fasting glucose and/or hypoglycemic medication use and were divided into three equal groups (tertiles) according to level of CRP or IL-6. Persistent functional limitation was defined as difficulty climbing 10 steps or walking one-quarter mile on two consecutive semiannual assessments. RESULTS -- At baseline, 702 participants (24%) had diabetes. CRP values were (median ± SD) 2.8 ± 4.4 versus 3.7 ± 5.4 for those with normal glucose and diabetes, respectively (P < 0.001). The unadjusted incidence of functional limitation associated with increased levels of CRP and IL-6 was greater among participants with diabetes. After adjusting for clinical and demographic covariates, persistent functional limitation for the highest tertile was greater compared with that for the lowest tertile of CRP or IL-6 for those with and without diabetes. CRP hazard ratios (HRs) were 1.7 (95% CI 1.2-2.3) versus 1.4 (1.1-1.6), respectively. IL-6 HRs were 1.8 (1.3-2.5) versus 1.6 (1.4-2.0), respectively. CONCLUSIONS -- In initially high-functioning older adults, those with diabetes and higher inflammatory burden had an increased risk of functional decline. Interventions at early stages to reduce inflammation may preserve function in these individuals. [ABSTRACT FROM AUTHOR]

Adequate skeletal muscle strength is essential for physical functioning and low muscle strength is a predictor of physical limitations. Older adults with diabetes have a two- to threefold increased risk of physical disability. However, muscle strength has never been investigated with regard to diabetes in a population-based study. We evaluated grip and knee extensor strength and muscle mass in 485 older adults with diabetes and 2,133 without diabetes in the Health, Aging, and Body Composition study. Older adults with diabetes had greater arm and leg muscle mass than those without diabetes because they were bigger in body size. Despite this, muscle strength was lower in men with diabetes and not higher in women with diabetes than corresponding counterparts. Muscle quality, defined as muscle strength per unit regional muscle mass, was significantly lower in men and women with diabetes than those without diabetes in both upper and lower extremities. Furthermore, longer duration of diabetes (≥6 years) and poor glycemic control (HbA1c < 8.0%) were associated with even poorer muscle quality. In conclusion, diabetes is associated with lower skeletal muscle strength and quality. These characteristics may contribute to the development of physical disability in older adults with diabetes. [ABSTRACT FROM AUTHOR]

Objective: To create a simple prediction rule that could perform as well as the 2-h postchallenge plasma glucose (PCPG) test to predict those at risk for diabetes. We created a prediction rule in one sample and prospectively validated it for incident diabetes in a separate cohort.Research Design and Methods: A cross-sectional analysis with data from the Rancho Bernardo Study (age 67 +/- 11 years) to derive a rule predicting abnormal PCPG >/=140 mg/dl, using demographic, clinical, and laboratory data of nondiabetic participants with fasting plasma glucose (FPG) <126 mg/dl. Data from the Health, Aging and Body Composition study (age 74 +/- 3 years) were used to prospectively validate this rule for incident diabetes and compare it with the predictive ability of the PCPG test.Results: Of 1,549 RBS participants, 514 (33%) had PCPG >/=140 mg/dl. Female sex, age, triglycerides, and FPG were most significantly associated with abnormal PCPG. Based on standardized beta-coefficients, we allotted 1 point for female sex, triglycerides >/=150 mg/dl, or FPG 95-104 mg/dl. Age >/=70 years or FPG 105-115 mg/dl were given 2 points, and FPG 116-125 mg/dl received 3 points. In the validation cohort, this simple prediction rule was as good as the 2-h PCPG test for predicting incident diabetes (C-statistic: 0.71 for both).Conclusions: Advanced age, female sex, FPG, and triglycerides were able to predict adults at risk for diabetes equally well as the 2-h PCPG test. Using this rule, clinicians may better identify older persons who should receive intensive lifestyle intervention to prevent type 2 diabetes. [ABSTRACT FROM AUTHOR]

OBJECTIVE -- To create a simple prediction rule that could perform as well as the 2-h postchallenge plasma glucose (PCPG) test to predict those at risk for diabetes. We created a prediction rule in one sample and prospectively validated it for incident diabetes in a separate cohort. RESEARCH DESIGN AND METHODS -- A cross-sectional analysis with data from the Rancho Bernardo Study (age 67 ± 11 years) to derive a rule predicting abnormal PCPG ≥140 mg/dl, using demographic, clinical, and laboratory data of nondiabetic participants with fasting plasma glucose (FPG) < 126 mg/dl. Data from the Health, Aging and Body Composition study (age 74 ± 3 years) were used to prospectively validate this rule for incident diabetes and compare it with the predictive ability of the PCPG test. RESULTS -- Of 1,549 RBS participants, 514 (33%) had PCPG ≥140 mg/dl. Female sex, age, triglycerides, and FPG were most significantly associated with abnormal PCPG. Based on standardized β-coefficients, we allotted 1 point for female sex, triglycerides ≥150 mg/dl, or FPG 95-104 mg/dl. Age ≥70 years or FPG 105-115 mg/dl were given 2 points, and FPG 116-125 mg/dl received 3 points. In the validation cohort, this simple prediction rule was as good as the 2-h PCPG test for predicting incident diabetes (C-statistic: 0.71 for both). CONCLUSIONS -- Advanced age, female sex, FPG, and triglycerides were able to predict adults at risk for diabetes equally well as the 2-h PCPG test. Using this rule, clinicians may better identify older persons who should receive intensive lifestyle intervention to prevent type 2 diabetes. [ABSTRACT FROM AUTHOR]

OBJECTIVE — We examined whether regional adipose tissue distribution, specifically that of skeletal muscle fat and visceral abdominal fat aggregation, is characteristic of elderly individuals with hyperinsulinemia , type 2 diabetes, and impaired glucose tolerance (IGT). RESEARCH DESIGN AND METHODS — A total of 2,964 elderly men and women (mean age 73.6 years) were recruited for cross-sectional comparisons of diabetes or glucose tolerance, generalized obesity with dual-energy X-ray absorptiometry, and regional body fat distribution with computed tomography RESULTS — Approximately one-third of men with type 2 diabetes and less than half of women with type 2 diabetes were obese (BMI ≥ 30 kg/m². Despite similar amounts of subcutaneous thigh fat, intermuscular fat was higher in subjects with type 2 diabetes and IGT than in subiects with normal glucose tolerance (NGT) (11.2 ± 9.4, 10.3 ± 5.8, and 9.2 ± 5.9 cm² for men; 12.1 ± 6.1, 10.9 ± 6.5, and 9.4 ± 5.3 cm² for women; both P < 0.0001). Visceral abdominal fat was also higher in men and women with type 2 diabetes and IGT than in subjects with NGT (172 ± 79, 163 ± 72, and 145 ± 66 cm² for men; 162 ± 66, 141 ± 60, and 116 ± 54 cm² for women; both P < 0.0001 across groups). Higher rates of intermuscular fat and visceral abdominal fat were associated with higher fasting insulin in normal-weight (BMI <25 kg/m²) men (r = 0.24 for intermuscular fat, r = 0.37 for visceral abdominal fat, both P < 0.0001) and women (r = 0.20 for intermuscular fat. r = 0.40 for visceral abdominal fat, both P < 0.0001). These associations were not found in obese subjects. CONCLUSIONS — Elderly men and women with normal body weight may be at risk for metabolic abnormalities, including type 2 diabetes, if they possess an inordinate amount of muscle fat or visceral abdominal fat. [ABSTRACT FROM AUTHOR]

Presents information on a study which assessed the prevalence and the factors associated with undiagnosed type 2 diabetes among the aged in the United States. Methodology; Results of the study; Conclusions.

OBJECTIVE -- To assess the risk factors for the presence and severity of obstructive sleep apnea (OSA) among obese patients with type 2 diabetes. RESEARCH DESIGN AND METHODS -- Unattended polysomnography was performed in 306 participants. RESULTS -- Over 86% of participants had OSA with an apnea-hypopnea index (AHI) ≥5 events/h. The mean AHI was 20.5 ± 16.8 events/h. A total of 30.5% of the participants had moderate OSA (15 ≤ AHI <30), and 22.6% had severe OSA (AHI ≥ 30). Waist circumference (odds ratio 1.1; 95% CI 1.0-1.1; P = 0.03) was significantly related to the presence of OSA. Severe OSA was most likely in individuals with a higher BMI (odds ratio 1.1; 95% CI 1.0-1.2; P = 0.03). CONCLUSIONS -- Physicians should be particularly cognizant of the likelihood of OSA in obese patients with type 2 diabetes, especially among individuals with higher waist circumference and BMI. [ABSTRACT FROM AUTHOR]

Older white women with type 2 diabetes (DM) may have higher fracture rates despite higher weight and bone mineral density, though little information exists for men, blacks or those with impaired fasting glucose (IFG). The Cardiovascular Health Study (CHS) included 5888 white and black men and women, followed 10.1±3.9 years for health events including incident hip fractures (ICD-9 codes 820.xx). Participants with hip fracture concurrent to motor vehicle accidents (N=9, ICD-9 E810-E825) or pathologic fracture (N=8, ICD-9 733.1) or missing fasting glucose (FG; N=358) were excluded. In 5513 participants, 419 hip fractures occurred. DM was defined as hypoglycemic medication use or FG ≥126 mg/dl and IFG was defined as FG ≥ 100 and < 126 mg/dl. Of participants (mean age 72.8±5.6 years; 42.4% men; 16% black), 17% had DM and 39% had IFG at baseline. Participants with DM or IFG were more likely men (49% and 46% vs. 36%; p<0.001) and those with DM were more likely black (24% vs. 16%; p<0.001) than those with normal FG. Crude hip fracture rates (/1000 person-years) were 8.5 (95%CI: 7.4-9.6) for normal FG, 6.6 (95%CI: 5.6-7.7) for IFG, and 7.3 (95%CI: 5.7-9.5) for DM. In Cox regression models adjusted for gender, race, age, body mass index (BMI), DM was significantly related to hip fractures (HR=l.37; 95%CI: 1.01-1.85). IFG was not related to hip fracture (HR=0.92; 95%CI: 0.74-1.14). There were no interactions of race or gender with DM or IFG and women and men had similar HR. Clinical cardiovascular disease, creatinine ≥1.5 mg/dl in men and ≥1.3 mg/dl in women, and vision problems did not attenuate the HR. However, ankle-arm index <0.9 reduced the HR for DM [1.28 (0.94-1.75)] and was marginally related to hip fracture [1.31 (0.99-1.72)]. DM was independently associated with 37% higher hip fracture risk after adjusting for higher BMI in diabetic participants. Older diabetic adults, possibly those with subclinical peripheral vascular disease, may need to be targeted for tincture prevention. ADA-Funded Research [ABSTRACT FROM AUTHOR]