Elsa S. Strotmeyer

Decreased Muscle Strength and Quality in Older Adults With Type 2 Diabetes: The Health, Aging, and Body Composition Study

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.

Accelerated Loss of Skeletal Muscle Strength in Older Adults With Type 2 Diabetes The Health, Aging, and Body Composition Study

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.

Association of BMD and FRAX score with risk of fracture in older adults with type 2 diabetes.

CONTEXT Type 2 diabetes mellitus (DM) is associated with higher bone mineral density (BMD) and paradoxically with increased fracture risk. It is not known if low BMD, central to fracture prediction in older adults, identifies fracture risk in patients with DM. OBJECTIVE To determine if femoral neck BMD T score and the World Health Organization Fracture Risk Algorithm (FRAX) score are associated with hip and nonspine fracture risk in older adults with type 2 DM. DESIGN, SETTING, AND PARTICIPANTS Data from 3 prospective observational studies with adjudicated fracture outcomes (Study of Osteoporotic Fractures [December 1998-July 2008]; Osteoporotic Fractures in Men Study [March 2000-March 2009]; and Health, Aging, and Body Composition study [April 1997-June 2007]) were analyzed in older community-dwelling adults (9449 women and 7436 men) in the United States. MAIN OUTCOME MEASURE Self-reported incident fractures, which were verified by radiology reports. RESULTS Of 770 women with DM, 84 experienced a hip fracture and 262 a nonspine fracture during a mean (SD) follow-up of 12.6 (5.3) years. Of 1199 men with DM, 32 experienced a hip fracture and 133 a nonspine fracture during a mean (SD) follow-up of 7.5 (2.0) years. Age-adjusted hazard ratios (HRs) for 1-unit decrease in femoral neck BMD T score in women with DM were 1.88 (95% confidence interval [CI], 1.43-2.48) for hip fracture and 1.52 (95% CI, 1.31-1.75) for nonspine fracture, and in men with DM were 5.71 (95% CI, 3.42-9.53) for hip fracture and 2.17 (95% CI, 1.75-2.69) for nonspine fracture. The FRAX score was also associated with fracture risk in participants with DM (HRs for 1-unit increase in FRAX hip fracture score, 1.05; 95% CI, 1.03-1.07, for women with DM and 1.16; 95% CI, 1.07-1.27, for men with DM; HRs for 1-unit increase in FRAX osteoporotic fracture score, 1.04; 95% CI, 1.02-1.05, for women with DM and 1.09; 95% CI, 1.04-1.14, for men with DM). However, for a given T score and age or for a given FRAX score, participants with DM had a higher fracture risk than those without DM. For a similar fracture risk, participants with DM had a higher T score than participants without DM. For hip fracture, the estimated mean difference in T score for women was 0.59 (95% CI, 0.31-0.87) and for men was 0.38 (95% CI, 0.09-0.66). CONCLUSIONS Among older adults with type 2 DM, femoral neck BMD T score and FRAX score were associated with hip and nonspine fracture risk; however, in these patients compared with participants without DM, the fracture risk was higher for a given T score and age or for a given FRAX score.

Association between hypoglycemia and dementia in a biracial cohort of older adults with diabetes mellitus

IMPORTANCE Hypoglycemia commonly occurs in patients with diabetes mellitus (DM) and may negatively influence cognitive performance. Cognitive impairment in turn can compromise DM management and lead to hypoglycemia. OBJECTIVE To prospectively evaluate the association between hypoglycemia and dementia in a biracial cohort of older adults with DM. DESIGN AND SETTING Prospective population-based study. PARTICIPANTS We studied 783 older adults with DM (mean age, 74.0 years; 47.0% of black race/ethnicity; and 47.6% female) who were participating in the prospective population-based Health, Aging, and Body Composition Study beginning in 1997 and who had baseline Modified Mini-Mental State Examination scores of 80 or higher. MAIN OUTCOME MEASURES Dementia diagnosis was determined during the follow-up period from hospital records indicating an admission associated with dementia or the use of prescribed dementia medications. Hypoglycemic events were determined during the follow-up period by hospital records. RESULTS During the 12-year follow-up period, 61 participants (7.8%) had a reported hypoglycemic event, and 148 (18.9%) developed dementia. Those who experienced a hypoglycemic event had a 2-fold increased risk for developing dementia compared with those who did not have a hypoglycemic event (34.4% vs 17.6%, P < .001; multivariate-adjusted hazard ratio, 2.1; 95% CI, 1.0-4.4). Similarly, older adults with DM who developed dementia had a greater risk for having a subsequent hypoglycemic event compared with participants who did not develop dementia (14.2% vs 6.3%, P < .001; multivariate-adjusted hazard ratio, 3.1; 95% CI, 1.5-6.6). Further adjustment for stroke, hypertension, myocardial infarction, and cognitive change scores produced similar results. CONCLUSION AND RELEVANCE Among older adults with DM, there seems to be a bidirectional association between hypoglycemia and dementia.

Pentosidine and increased fracture risk in older adults with type 2 diabetes

CONTEXT Type 2 diabetes is associated with higher fracture risk at a given bone mineral density. Advanced glycation endproducts (AGEs) accumulate in bone collagen with age and diabetes and may weaken bone. OBJECTIVE The aim was to determine whether urine pentosidine, an AGE, was associated with fractures in older adults with and without diabetes. DESIGN We performed an observational cohort study. SETTING We used data from the Health, Aging and Body Composition prospective study of white and black, well-functioning men and women ages 70-79 yr. PARTICIPANTS Participants with (n = 501) and without (n = 427) diabetes were matched on gender, race, and study site. PREDICTOR Urine pentosidine was assayed from frozen stored baseline specimens. MAIN OUTCOME MEASURES Incident clinical fractures and baseline vertebral fractures were measured. RESULTS Despite higher bone mineral density, clinical fracture incidence (14.8 vs. 12.6%) and vertebral fracture prevalence (2.3 vs. 2.9%) were not lower in those with diabetes (P > 0.05). In multivariable models, pentosidine was associated with increased clinical fracture incidence in those with diabetes [relative hazard, 1.42; 95% confidence interval (CI), 1.10, 1.83, for 1 sd increase in log pentosidine] but not in those without diabetes (relative hazard, 1.08; 95% CI, 0.79, 1.49; P value for interaction = 0.030). In those with diabetes, pentosidine was associated with increased vertebral fracture prevalence (adjusted odds ratio, 5.93; 95% CI, 2.08, 16.94, for 1 sd increase in log pentosidine) but not in those without diabetes (adjusted odds ratio, 0.74; 95% CI, 0.30, 1.83; P value for interaction = 0.005). CONCLUSIONS Higher pentosidine levels are a risk factor for fracture in older adults with diabetes and may account in part for reduced bone strength in type 2 diabetes.

Diabetes is associated independently of body composition with BMD and bone volume in older white and black men and women: The Health, Aging, and Body Composition Study.

The association between type 2 diabetes, BMD, and bone volume was examined to determine the effect of lean and fat mass and fasting insulin in the Health, Aging, and Body Composition Study, which included white and black well‐functioning men and women 70‐79 years of age (N = 2979). Diabetes predicted higher hip, whole body, and volumetric spine BMD, and lower spine bone volume, independent of body composition and fasting insulin.

Diabetes, Glucose Control, and 9-Year Cognitive Decline Among Older Adults Without Dementia

OBJECTIVES To determine if prevalent and incident diabetes mellitus (DM) increase risk of cognitive decline and if, among elderly adults with DM, poor glucose control is related to worse cognitive performance. DESIGN Prospective cohort study. SETTING Health, Aging, and Body Composition Study at 2 community clinics. PARTICIPANTS A total of 3069 elderly adults (mean age, 74.2 years; 42% black; 52% female). MAIN OUTCOME MEASURES Participants completed the Modified Mini-Mental State Examination (3MS) and Digit Symbol Substitution Test (DSST) at baseline and selected intervals over 10 years. Diabetes mellitus status was determined at baseline and during follow-up visits. Glycosylated hemoglobin A1c level was measured at years 1 (baseline), 4, 6, and 10 from fasting whole blood. RESULTS At baseline, 717 participants (23.4%) had prevalent DM and 2352 (76.6%) were without DM, 159 of whom developed incident DM during follow-up. Participants with prevalent DM had lower baseline test scores than participants without DM (3MS: 88.8 vs 90.9; DSST: 32.5 vs 36.3, respectively; t = 6.09; P = .001 for both tests). Results from mixed-effects models showed a similar pattern for 9-year decline (3MS: -6.0- vs -4.5-point decline; t = 2.66; P = .008; DSST: -7.9- vs -5.7-point decline; t = 3.69; P = .001, respectively). Participants with incident DM tended to have baseline and 9-year decline scores between the other 2 groups but were not statistically different from the group without DM. Multivariate adjustment for demographics and medical comorbidities produced similar results. Among participants with prevalent DM, glycosylated hemoglobin A1c level was associated with lower average mean cognitive scores (3MS: F = 8.2; P for overall = .003; DSST: F = 3.4; P for overall = .04), even after multivariate adjustment. CONCLUSION Among well-functioning older adults, DM and poor glucose control among those with DM are associated with worse cognitive function and greater decline. This suggests that severity of DM may contribute to accelerated cognitive aging.

Knee extension strength cutpoints for maintaining mobility

OBJECTIVES: To identify levels of knee extensor strength that are associated with high and low risk of incident severe mobility limitation (SML) in initially well‐functioning older adults.

Diabetes and bone loss at the hip in older black and white adults.

Type 2 diabetes may be associated with elevated fracture risk, but the impact on bone loss is unknown. Analysis of 4‐year change in hip BMD data from a cohort of white and black well‐functioning men and women 70‐79 years of age found that white women with diabetes had more rapid bone loss at the femoral neck than those with normal glucose metabolism.

Bone mass and strength in older men with type 2 diabetes: The Osteoporotic Fractures in Men Study

The effects of type 2 diabetes mellitus (T2DM) on bone volumetric density, bone geometry, and estimates of bone strength are not well established. We used peripheral quantitative computed tomography (pQCT) to compare tibial and radial bone volumetric density (vBMD, mg/cm3), total (ToA, mm2) and cortical (CoA, mm2) bone area and estimates of bone compressive and bending strength in a subset (n = 1171) of men (≥65 years of age) who participated in the multisite Osteoporotic Fractures in Men (MrOS) study. Analysis of covariance–adjusted bone data for clinic site, age, and limb length (model 1) and further adjusted for body weight (model 2) were used to compare data between participants with (n = 190) and without (n = 981) T2DM. At both the distal tibia and radius, patients with T2DM had greater bone vBMD (+2% to +4%, model 1, p < .05) and a smaller bone area (ToA −1% to −4%, model 2, p < .05). The higher vBMD compensated for lower bone area, resulting in no differences in estimated compressive bone strength at the distal trabecular bone regions. At the mostly cortical bone midshaft sites of the radius and tibia, men with T2DM had lower ToA (−1% to −3%, p < .05), resulting in lower bone bending strength at both sites after adjusting for body weight (−2% to −5%, p < .05) despite the lack of difference in cortical vBMD at these sites. These data demonstrate that older men with T2DM have bone strength that is low relative to body weight at the cortical‐rich midshaft of the radius despite no difference in cortical vBMD.