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Objectives: To quantify the longitudinal change in stair climb performance (a measure indicative of both physical function and muscle power), determine whether physical activity is related to slower decline in performance, and to identify factors that modify the longitudinal change in performance among women from midlife to late life. Design: Longitudinal cohort study with up to 15 study visits. Setting: Two sites of the Study of Women's Health Across the Nation. Participants: Black (n=411) and white (N=419) women followed from median age 47.0 (44.6–49.6) to 62.0 (55.8–65.3) years. Interventions: N/A. Measurements: Performance on a stair climb test (ascend/descend 4 steps, 3 cycles) was timed. Physical activity (PA) was assessed using the Kaiser Physical Activity Survey (KPAS; possible range 0–15 points). Sociodemographic and health factors were assessed via self-report. BMI was calculated with measured height and weight. Mixed-effects regression modeled longitudinal change in stair climb performance. Results: Average baseline stair climb time was 18.12 seconds (95% CI: 17.83–18.41), with 0.98% (95% CI: 0.84%–1.11%) annual slowing. In fully adjusted models, higher levels of PA were associated with faster stair climb times (2.09% faster per point higher, 95% CI: −2.87%–1.30%), and black women had 5.22% (95% CI: 2.43%–8.01%) slower performance compared to white women. Smoking, financial strain, diabetes, osteoarthritis, fair/poor health, and stroke were associated with 3.36% (95% CI: 0.07%–6.65%), 7.56% (95% CI: 4.75%–10.37%), 8.40% (95% CI: 2.89%–13.92%), 8.46% (95% CI: 5.12%–11.79%), 9.16% (95% CI: 4.72%–13.60%), and 16.94% (95% CI: 5.37%–28.51%) slower performance, respectively. In separate models, higher BMI (per 1-unit), osteoarthritis, fair/poor health, and diabetes, were each associated with 0.06% (95% CI:0.04%–0.08%), 0.48% (95% CI:0.12%–0.84%), 0.81% (95% CI:0.35%–1.28%), and 0.84% (95% CI:0.22%–1.46%), additional slowing per year over time. Conclusion: Significant declines in function were evident as women transitioned from midlife to early late life. Declines were amplified by indicators of poor health, emphasizing the importance of health in midlife for promoting healthy aging. [ABSTRACT FROM AUTHOR]

Background: In older adults, impaired control of standing balance in the lateral direction is associated with the increased risk of falling. Assessing the factors that contribute to impaired standing balance control may identify areas to address to reduce falls risk.Aim: To investigate the contributions of physiological factors to standing lateral balance control.Methods: Two hundred twenty-two participants from the Pittsburgh site of the Health, Aging and Body Composition Study had lateral balance control assessed using a clinical sensory integration balance test (standing on level and foam surface with eyes open and closed) and a lateral center of pressure tracking test using visual feedback. The center of pressure was recorded from a force platform. Multiple linear regression models examined contributors of lateral control of balance performance, including concurrently measured tests of lower extremity sensation, knee extensor strength, executive function, and clinical balance tests. Models were adjusted for age, body mass index, and sex.Results: Larger lateral sway during the sensory integration test performed on foam was associated with longer repeated chair stands time. During the lateral center of pressure tracking task, the error in tracking increased at higher frequencies; greater error was associated with worse executive function. The relationship between sway performance and physical and cognitive function differed between women and men.Discussion: Contributors to control of lateral balance were task-dependent. Lateral standing performance on an unstable surface may be more dependent upon general lower extremity strength, whereas visual tracking performance may be more dependent upon cognitive factors.Conclusions: Lateral balance control in ambulatory older adults is associated with deficits in strength and executive function. [ABSTRACT FROM AUTHOR]

Summary: Obesity appears protective against osteoporosis in cross-sectional studies. However, results from this longitudinal study found that obesity was associated with bone loss over time. Findings underscore the importance of looking at the longitudinal relationship, particularly given the increasing prevalence and duration of obesity among older adults. Introduction: Cross-sectional studies have found a positive association between body mass index (BMI) and bone mineral density (BMD), but little is known about the longitudinal relationship in US older adults. Methods: We examined average annual rate of change in BMD by baseline BMI in the Health, Aging, and Body Composition Study. Repeated measurement of BMD was performed with dual-energy X-ray absorptiometry (DXA) at baseline and years 3, 5, 6, 8, and 10. Multivariate generalized estimating equations were used to predict mean BMD (femoral neck, total hip, and whole body) by baseline BMI (excluding underweight), adjusting for covariates. Results: In the sample ( n = 2570), 43 % were overweight and 24 % were obese with a mean baseline femoral neck BMD of 0.743 g/cm, hip BMD of 0.888 g/cm, and whole-body BMD of 1.09 g/cm. Change in total hip or whole-body BMD over time did not vary by BMI groups. However, obese older adults lost 0.003 g/cm of femoral neck BMD per year more compared with normal weight older adults ( p < 0.001). Femoral neck BMD change over time did not differ between the overweight and normal weight BMI groups ( p = 0.74). In year 10, adjusted femoral neck BMD ranged from 0.696 g/cm among obese, 0.709 g/cm among normal weight, and 0.719 g/cm among overweight older adults. Conclusions: Findings underscore the importance of looking at the longitudinal relationship between body composition and bone mineral density among older adults, indicating that high body mass may not be protective for bone loss over time. [ABSTRACT FROM AUTHOR]

Background/Objective: Obesity exacerbates age-related physical disability; however, observational studies show that any weight loss in old age is associated with greater risk of mortality. Conversely, randomized controlled trials in older adults show that weight loss is beneficial. The discrepancy may be due to weight loss intention and differential changes to regional body composition. The purpose of this research was to evaluate the independent role of regional body composition remodeling in improving physical function. Design: Pilot Randomized Controlled Trial. Setting: Community based research center. Participants: Thirty-six community dwelling, overweight to moderately obese (BMI 28.0-39.9 kg/m) older adults (age 70.6±6.1 yrs). Intervention: Physical activity plus weight loss (PA+WL, n=21) or PA plus successful aging (SA) education. PA consisted primary of treadmill walking supplemented with lower extremity resistance and balance training. The WL program was based on the Diabetes Prevention Project and aimed at achieving a 7% weight loss by cutting calories, specifically those from fat. Measurements: At baseline, 6- and 12-months, body composition was measured using computerized tomography and dual x-ray absorptiometry. Abdominal visceral (VAT) and thigh intermuscular (IMAT) adipose tissue were quantified. Physical function was assessed using the short physical performance battery (SPPB). Results: Separate multivariable linear regression models with both groups combined demonstrated that decreases in IMAT and VAT were significantly associated with improvements in SPPB (P<0.05) independent of change in total fat mass. PA+WL improved SPPB scores from baseline (0.8±1.4, P<0.05), whereas PA+SA did not; however no intergroup difference was detected. Of note, these effects were mainly achieved during the intensive intervention phase. Conclusion: Decreases in IMAT and VAT are important mechanisms underlying improved function following intentional weight loss plus physical activity. [ABSTRACT FROM AUTHOR]

Summary: The effect of abdominal adiposity and muscle on fracture is unclear in older men; therefore, we examined the association among 749 men aged 65+. Among various adipose tissues and muscle groups, lower psoas muscle volume and higher fatty infiltration of abdominal muscle contribute to higher fracture risk independent of BMD. Introduction: The association of abdominal adiposity and muscle composition with incident fracture is unclear, especially in older men. Therefore, we examined the relationship of subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), abdominal intermuscular adipose tissue (IMAT), and muscle volume with incident non-spine fractures among 749 men aged 65 and older. Methods: A case-cohort study design was used with a total of 252 fracture cases and 497 non-cases. We measured volumes (in centimeters) of adipose and muscle tissues obtained from quantitative computed tomography scan at the L4-5 intervertebral space. Three groups of muscle and IMAT were evaluated: total abdominal, psoas, and paraspinal. Cox proportional hazards regression with a robust variance estimator was used to estimate the hazard ratio (HR) of non-spine fractures per standard deviation (SD) increase in the abdominal body composition measures. The mean age among men in the random subcohort was 74.2 ± 6.1 years, and the average follow-up time was 5.2 ± 1.1 years. Results: After adjusting for age, race, clinic site, percent body fat, and femoral neck bone mineral density (BMD), no significant relationship was found between incident fractures and SAT or VAT. One SD increase in muscle volume at the psoas, but not paraspinal, was associated with 28 % lower fracture risk (95 % CI = 0.55-0.95). When IMAT models were further adjusted for corresponding muscle volumes, only abdominal IMAT was significantly associated with fracture risk (HR = 1.30 (95 % CI = 1.04-1.63)). Conclusion: Our findings suggest that lower total psoas muscle volume and higher IMAT of the total abdominal muscle contribute to higher fracture risk in older men independent of BMD. [ABSTRACT FROM AUTHOR]

Summary: We tested the hypothesis that low leptin and high adiponectin levels are associated with higher rates of bone mineral density (BMD) loss among 3,075 men and women, aged 70-79, from the Health Aging and Body Composition Study. Results suggest that adiponectin, but not leptin, is a risk factor for bone loss in women. Introduction: Adiponectin and leptin are hormones secreted by adipose cells that may impact BMD. Few studies have evaluated the longitudinal association of leptin and adiponectin levels with rates of BMD change. Methods: Hip and whole-body areal BMD (aBMD) were measured five times using dual-energy X-ray absorptiometry over 10 years (average follow-up time, 7.95 ± 1.92 years). Trabecular lumbar spine volumetric BMD (vBMD) was measured using quantitative computed topography at baseline and year 6 in the Pittsburgh cohort only. Random slope and intercept models were used to account for within person correlation as a result of repeated measures of hip and whole-body aBMD. Linear regression was used to model changes in spine trabecular vBMD. Results: Among women, the annualized rate of hip aBMD loss in the highest tertile of adiponectin was −0.67% (95% CI −0.77, −0.58) compared to [−0.43% (95% CI −0.51, −0.35)] in the lowest tertile ( p trend = 0.019) after adjusting for age, race, BMI, diabetes, baseline hip aBMD, and weight change. In men, hip aBMD loss was greatest in the high adiponectin group (tertile 3), however this association was not significant ( p trend = 0.148). After adjusting for weight change in women, the association between higher leptin and lower hip aBMD loss was attenuated and no longer significant ( p trend = 0.134). Leptin and adiponectin levels were not associated with whole-body aBMD or trabecular lumbar spine vBMD loss. Conclusions: Adiponectin was associated with increased hip aBMD loss in women only, supporting evidence that adiponectin may have an important role in bone health. [ABSTRACT FROM AUTHOR]

Summary: We examined the association of serum 25-hydroxyvitamin D [25(OH)D] with indices of bone quality in older men. Positive associations for 25(OH)D and bone mineral density, content, cortical thickness, and axial and polar strength strain indices were observed among Caucasians; however, among men of African descent findings were either null or negative. Introduction: There are limited data on serum 25(OH)D and bone measures in men of African ancestry. To better understand racial differences in vitamin D status and bone health, a cross-sectional study among 446 Caucasian men in the US and 496 men of African ancestry in Tobago (age ≥ 65 years) was conducted. Methods: Serum 25(OH)D (liquid chromatography and tandem mass spectrometry) was measured, and peripheral quantitative computed tomography scans were administered. Bone measures estimated included trabecular and cortical volumetric bone mineral density (vBMD), bone mineral content (BMC), bone geometry (cross-sectional area and cortical thickness), and polar and axial strength strain indices (SSIp and SSIx). Results: Men of African ancestry had higher 25(OH)D than Caucasians (34.7 vs. 27.6 ng/ml, p < 0.01). Among Caucasians, 25(OH)D was positively ( p trend < 0.05) associated with cortical vBMD, total BMC, cortical thickness, SSIp, and SSIx at the distal radius after adjustment for potential confounders. Similar patterns were observed at the distal tibia. In contrast, in men of African ancestry, there was an inverse association ( p trend < 0.05) between 25(OH)D and the cross-sectional area, and SSIx. Race modified ( p for interaction < 0.05) the association between 25(OH)D and total BMC, cross-sectional area, SSIp, SSIx, and trabecular vBMD of the radius. In men of African ancestry, there was evidence of a threshold effect (at approximately 18 ng/ml) for 25(OH)D on tibial total BMC and cortical thickness. Conclusions: More studies are needed to better comprehend these race differences for 25(OH)D and bone density, geometry, and indices of bone strength. [ABSTRACT FROM AUTHOR]

Summary: The purpose of this study was to evaluate the rate of bone loss and incident fractures in women with diabetes mellitus (DM) across menopause. During menopause, DM women experienced bone mineral density (BMD) loss that was faster at hip and slower at spine and had a higher risk of fractures, perhaps because of their earlier menopause. The increasing DM epidemic will contribute to higher fracture burden. Introduction: Women with DM have a higher risk of fractures independent of age, body mass index (BMI), and BMD. Our objective is to evaluate if women with DM experience greater bone loss and more fractures across menopause. Methods: Two thousand one hundred seventy one women, aged 42 to 52 years at baseline (1996), enrolled in the Study of Women's Health Across the Nation (SWAN), a prospective study, with 8 years of annual follow up. One thousand three hundred forty six (62%) completed annual visit 7 (2004). Women with baseline fasting blood glucose level of ≥126 mg/dl and those being treated for diabetes were designated as DM. Annual assessment of menopausal stage, BMD, and urinary N-telopeptide (NTx) were carried out. Rate of change in BMD across menopause and annual self-report data for risk of incident fractures by DM status were determined. Results: Despite higher baseline BMD at hip ( p = <0.001), and lumbar spine ( p = <0.001), rate of decline in BMD was faster at hip ( β = −0.45 vs. −0.11 gm/cm/year, p = <0.001) for DM women, compared to non-DM. However, lumbar spine bone loss was slower in women with DM as compared to non-DM women ( β = 0.04 vs. −0.25 gm/cm/year, p = 0.004). DM women experienced menopause 3 years earlier than non-DM women ( p = 0.002), and age adjusted incident fractures were two fold higher in women with DM compared to non-DM (RR = 2.20, 95% CI: 1.26-3.85, p = <0.006). Conclusions: BMD loss is greater in hip and slower at spine in DM women during menopausal transition. Women with DM have a higher risk of fractures, perhaps because of their earlier menopause. [ABSTRACT FROM AUTHOR]

The associations of volumetric (vBMD) and areal (aBMD) bone mineral density measures with prevalent cardiovascular disease (CVD) and subclinical peripheral arterial disease (PAD) were investigated in a cohort of older men and women enrolled in the Health, Aging, and Body Composition Study. Participants were 3,075 well-functioning white and black men and women (42% black, 51% women), aged 68–80 years. Total hip, femoral neck, and trochanter aBMD were measured using dual-energy X-ray absorptiometry. Quantitative computed tomography was used to evaluate spine trabecular, integral, and cortical vBMD measures in a subgroup ( n = 1,489). Logistic regression was performed to examine associations of BMD measures with CVD and PAD. The prevalence of CVD (defined by coronary heart disease, PAD, cerebrovascular disease, or congestive heart failure) was 29.8%. Among participants without CVD, 10% had subclinical PAD (defined as ankle-arm index <0.9). Spine vBMD measures were inversely associated with CVD in men (odds ratio of integral [ORintegral] = 1.34, 95% confidence interval [CI] 1.10–1.63; ORtrabecular = 1.25, 95% CI 1.02–1.53; ORcortical = 1.36, 95% CI 1.11–1.65). In women, for each standard deviation decrease in integral vBMD, cortical vBMD, or trochanter aBMD, the odds of CVD were significantly increased by 28%, 27%, and 22%, respectively. Total hip aBMD was associated with subclinical PAD in men (OR = 1.39, 95% CI 1.03–1.84) but not in women. All associations were independent of age and shared risk factors between BMD and CVD and were not influenced by inflammatory cytokines (interleukin-6 and tumor necrosis factors-α). In conclusion, our results provide further evidence for an inverse association between BMD and CVD in men and women. Future research should investigate common pathophysiological links for osteoporosis and CVD. [ABSTRACT FROM AUTHOR]