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Biomedical subjects

Frances A Tylavsky

Publications and source records attributed to Frances A Tylavsky.

At least 19 recordsLinked to original sources
PubMed2006

Changes in bone mineral density in survivors of childhood acute lymphoblastic leukemia.

BACKGROUND: There is little information about factors modulating bone mineral density (BMD) in survivors of childhood acute lymphoblastic leukemia (ALL). PROCEDURE: We analyzed data from 57 survivors (26 male, 52 Caucasian) who underwent two serial quantitative computed tomography (QCT) studies of BMD. Using multiple linear regression, we evaluated the association of BMD change with demographic variables, treatment history, hormone therapy, exercise, and tobacco and alcohol use. RESULTS: The median age was 3.4 years (range, 0.9-17.4 years) at diagnosis of ALL; the median age at the first QCT (Study I) was 15.0 years (range, 10.6-31.0 years) and at the second QCT (Study II) was 18.2 years (range, 14.2-35.3 years). Mean height increased 4.7 cm and mean weight increased 8.8 kg between Studies I and II. While the mean BMD increased 9.33 mg/cc (P = 0.003), the BMD Z-score increased only slightly (0.21 SD, P = 0.035). Cortical bone density increased significantly (approximately 25.3 mg/cc; P = 0.001), but the ratio of trabecular to cortical BMD decreased significantly (P = 0.045). Factors independently associated with unfavorable BMD changes included older age at diagnosis (P = 0.001), female sex (P = 0.018), and nutritional supplementation (0.032). Alcohol (P = 0.009) was an unfavorable factor in a univariable analysis. CONCLUSIONS: Bone mineral accretion during adolescence is attenuated in childhood ALL survivors by a comparative deficit in trabecular versus cortical bone deposition. BMD is influenced favorably by exercise in early adolescence and unfavorably by the use of nutritional supplements and alcohol. These results provide new information about behavioral factors that affect bone accrual in survivors of childhood ALL and warrant definitive evaluation in a larger cohort.

Adolescent↗
PubMed2006

QCT versus DXA in 320 survivors of childhood cancer: association of BMD with fracture history.

PURPOSE: To assess agreement on diagnosis of diminished bone mineral density (BMD) and correlation between BMD values obtained by dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT) in childhood cancer survivors. PATIENTS AND METHODS: We retrospectively reviewed lumbar spine QCT and DXA studies for BMD in patients who underwent both imaging studies within a 24-hr period. We determined correlation between BMD values and agreement on diagnosis of diminished BMD obtained by both modalities. Diminished BMD was defined as two or more SDs below mean for age- and gender-matched reference values. We evaluated the relationship of BMD values determined by each modality to self-reported fracture history in the 160 (50%) patients with available reports. RESULTS: Of 320 patients, 56% (178) were male; 87% (277) were white. Median age was 16.4 (range, 5.1-36.0) years. Median BMD Z-score was -1.43 (range, -5.96 to 3.20) by QCT and -1.30 (range, -5.50 to 2.80) by DXA. Correlation between QCT- and DXA-determined BMD values was significant but low, and agreement on diminished BMD was fair (kappa = 0.32). There was no association between BMD measured by either QCT or DXA and self-reported traumatic fracture history. Male gender was associated with doubling the traumatic fracture risk (P = 0.0499). CONCLUSIONS: Quantitative computed tomography and DXA may give discrepant results when used to assess bone health in childhood cancer survivors, especially in those of non-white race. This inconsistency in indicators of BMD deficiency may complicate clinical decision-making. Consecutive use of a single modality is recommended to provide reliable longitudinal information.

Absorptiometry, Photon↗
PubMed2006

Strength, but not muscle mass, is associated with mortality in the health, aging and body composition study cohort.

BACKGROUND: Although muscle strength and mass are highly correlated, the relationship between direct measures of low muscle mass (sarcopenia) and strength in association with mortality has not been examined. METHODS: Total mortality rates were examined in the Health, Aging and Body Composition (Health ABC) Study in 2292 participants (aged 70-79 years, 51.6% women, and 38.8% black). Knee extension strength was measured with isokinetic dynamometry, grip strength with isometric dynamometry. Thigh muscle area was measured by computed tomography (CT) scan, and leg and arm lean soft tissue mass were determined by dual energy x-ray absorptiometry (DXA). Both strength and muscle size were assessed as in gender-specific Cox proportional hazards models, with age, race, comorbidities, smoking status, level of physical activity, fat area by CT or fat mass by DXA, height, and markers of inflammation, including interleukin-6, C-reactive protein, and tumor necrosis factor-alpha considered as potential confounders. RESULTS: There were 286 deaths over an average of 4.9 (standard deviation = 0.9) years of follow-up. Both quadriceps and grip strength were strongly related to mortality. For quadriceps strength (per standard deviation of 38 Nm), the crude hazard ratio for men was 1.51 (95% confidence interval, 1.28-1.79) and 1.65 (95% confidence interval, 1.19-2.30) for women. Muscle size, determined by either CT area or DXA regional lean mass, was not strongly related to mortality. In the models of quadriceps strength and mortality, adjustment for muscle area or regional lean mass only slightly attenuated the associations. Further adjustment for other factors also had minimal effect on the association of quadriceps strength with mortality. Associations of grip strength with mortality were similar. CONCLUSION: Low muscle mass did not explain the strong association of strength with mortality, demonstrating that muscle strength as a marker of muscle quality is more important than quantity in estimating mortality risk. Grip strength provided risk estimates similar to those of quadriceps strength.

Age Factors↗
PubMed2006

The loss of skeletal muscle strength, mass, and quality in older adults: the health, aging and body composition study.

BACKGROUND: The loss of muscle mass is considered to be a major determinant of strength loss in aging. However, large-scale longitudinal studies examining the association between the loss of mass and strength in older adults are lacking. METHODS: Three-year changes in muscle mass and strength were determined in 1880 older adults in the Health, Aging and Body Composition Study. Knee extensor strength was measured by isokinetic dynamometry. Whole body and appendicular lean and fat mass were assessed by dual-energy x-ray absorptiometry and computed tomography. RESULTS: Both men and women lost strength, with men losing almost twice as much strength as women. Blacks lost about 28% more strength than did whites. Annualized rates of leg strength decline (3.4% in white men, 4.1% in black men, 2.6% in white women, and 3.0% in black women) were about three times greater than the rates of loss of leg lean mass ( approximately 1% per year). The loss of lean mass, as well as higher baseline strength, lower baseline leg lean mass, and older age, was independently associated with strength decline in both men and women. However, gain of lean mass was not accompanied by strength maintenance or gain (ss coefficients; men, -0.48 +/- 4.61, p =.92, women, -1.68 +/- 3.57, p =.64). CONCLUSIONS: Although the loss of muscle mass is associated with the decline in strength in older adults, this strength decline is much more rapid than the concomitant loss of muscle mass, suggesting a decline in muscle quality. Moreover, maintaining or gaining muscle mass does not prevent aging-associated declines in muscle strength.

Aged↗
PubMed2006

Strategies to improve vitamin D status in northern European children: exploring the merits of vitamin D fortification and supplementation.

Adequacy of vitamin D in children in Europe has been the focus of a number of investigations. The results of measuring serum levels of 25-hydroxyvitamin D show high prevalence of vitamin D deficiency during the winter with lower prevalence during the summer. National policies on food fortification or individual supplementation with vitamin D have been recently revisited by the individual countries and the European Union as a whole. Optiford is a project managed by a coalition of scientists formed to optimize vitamin D fortification in the northern European Countries, was given the task to decide if food fortification with vitamin D is feasible and to provide a scientific basis for setting the vitamin D fortification level in Europe. This article presents the results of these investigations to date, with particular attention to potential corrective strategies to allow children and adolescents living in countries at high latitudes to maintain healthy circulating 25-hydroxyvitamin D levels year around, even in the absence of adequate sun exposure during a significant part of the year.

Adolescent↗
PubMed2006

Correlates of use of antifracture therapy in older women with low bone mineral density.

BACKGROUND: Guidelines exist for treatment of low bone mineral density (BMD). Little is known about patient characteristics associated with use of treatment. OBJECTIVES: To determine patient-related correlates of medication use following screening dual x-ray absorptiometry (DXA) of older adults. DESIGN: Secondary analysis of a prospective cohort study. SETTING: Pittsburgh, PA and Memphis, TN. PARTICIPANTS: Community-dwelling women between the ages 70 and 79 years enrolled in the Health, Aging, and Body Composition (Health ABC) Study. MEASUREMENTS: Risk factors for fracture and BMD of the hip were assessed at baseline. Patients and their community physicians were supplied the results of the DXA scan. Prescription and over-the-counter medication use was collected at annual exams for 2 years. RESULTS: Of 1,584 women enrolled in Health ABC, 378 had an indication for antifracture therapy and were not receiving such treatment at baseline. By the second annual follow-up examination, prescription antiresorptive medication was reported in 49 (13.0%), whereas 65 (17.2%) received calcium and/or vitamin D supplementation. In adjusted models, the strongest predictor for use of any antifracture medicine was presence of osteoporosis [vs osteopenia, odds ratio (OR), 2.9 (1.7 to 4.7)], white race [OR, 2.6 (1.5 to 4.8)], and receipt of the flu shot [OR, 2.2 (1.3 to 3.8)]. Neither a history of falls nor prior fracture was associated with use of antifracture medications. CONCLUSION: Even when physicians of study participants were provided with DXA scan results, 70% of older high-functioning women with an indication for therapy did not start or remain on an antifracture therapy. Substantial room for improvement exists in fracture prevention following a diagnosis of low BMD-especially among women with a history of falls, prior fractures, and among black women.

Aged↗
PubMed2006

Reduced peripheral nerve function is related to lower hip BMD and calcaneal QUS in older white and black adults: the Health, Aging, and Body Composition Study.

UNLABELLED: Bone tissue is innervated, and peripheral nerve function may impact BMD. Older black and white men and women (N = 2200) in the Health, Aging, and Body Composition Study with worse sensory and motor peripheral nerve function had lower hip BMD and calcaneal BUA independent of lean mass, strength, physical ability, and diabetes. Poor peripheral nerve function may directly affect bone. INTRODUCTION: Bone tissue is innervated, yet little is known about the impact of nerve function on BMD. Poor peripheral nerve function may contribute to lower BMD and higher fracture risk, particularly in those with diabetic neuropathy. MATERIALS AND METHODS: The Health, Aging, and Body Composition (Health ABC) Study included annual exams in white and black men and women 70-79 years of age recruited from Pittsburgh and Memphis. Nerve function in legs/feet was assessed by 1.4- and 10-g monofilament detection, vibration threshold, and peroneal motor nerve conduction velocity (NCV) and amplitude (CMAP). Total hip BMD, heel broadband ultrasound attenuation (BUA), and total fat and lean mass were measured 1 year later (QDR 4500A, Sahara QUS; Hologic). RESULTS: Participants (N = 2200) were 48% men and 37% black. Poor nerve function (lower monofilament detection, higher vibration threshold, lower CMAP, lower NCV) was associated with 1.4-5.7% lower BUA and significant for all but NCV, adjusted for demographics, diabetes, body composition, and physical ability. Results were similar for adjusted hip BMD, with 1.0-2.9% lower BMD, significant for monofilament and CMAP testing. When considering the components of BMD, total hip area was 1.8-4.9% higher in those with the worst nerve function, although BMC showed little difference. Lower monofilament detection and CMAP were independently associated with lower heel BUA (p < 0.01), and monofilament detection was associated with lower hip BMD (p < 0.05) in regression additionally adjusted for lifestyle factors, bone-active medications, and diabetes-related complications. CONCLUSIONS: Poor peripheral nerve function may directly related to lower BMD, likely through an increase in bone area in older adults, independent of lean mass, strength, physical ability, and diabetes. Whether those with impaired nerve function are at higher risk for fracture independent of falls needs to be studied.

Aged↗
PubMed2006

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 (>or=6 years) and poor glycemic control (HbA(1c) >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.

Aged↗
PubMed2005

Cystatin C and mortality risk in the elderly: the health, aging, and body composition study.

Kidney dysfunction is known to decrease life expectancy in the elderly. Cystatin C is a novel biomarker of kidney function that may have prognostic utility in older adults. The association of cystatin C with mortality was evaluated in a biracial cohort of black and white ambulatory elderly and compared with that of serum creatinine concentrations. The Health, Aging and Body Composition study is a cohort of well-functioning elderly that was designed to evaluate longitudinal changes in weight, body composition, and function. A total of 3075 participants who were aged 70 to 79 yr and had no disability were recruited at sites in Memphis, TN, and Pittsburgh, PA, between April 1997 and June 1998 with a follow-up of 6 yr. At entry, the mean cystatin C was 1.05 mg/L and the mean creatinine was 1.06 mg/dl. After 6 yr of follow-up, 557 participants had died. The mortality rates in each ascending cystatin C quintile were 1.7, 2.7, 2.9, 3.1, and 5.4%/yr. After adjustment for demographic risk factors, comorbid health conditions, and inflammatory biomarkers (C-reactive protein, IL-6. and TNF-alpha), each quintile of cystatin C was significantly associated with increased mortality risk compared with the lowest: Hazard ratios (HR; 95% confidence intervals) quintile 1, -1.0 (referent); quintile 2, -1.74 (1.21 to 2.50); quintile 3, -1.51 (1.05 to 2.18); quintile 4, -1.49 (1.04 to 2.13); and quintile 5, -2.18 (1.53 to 3.10). These associations did not differ by gender or race. Results were consistent for cardiovascular and other-cause mortality, but not cancer mortality. Creatinine quintiles were not associated with mortality after multivariate adjustment (HR: 1.0 [referent], 1.00 [0.72 to 1.39], 0.95 [0.68 to 1.32], 1.11 [0.79 to 1.57], 1.16 [0.86 to 1.58]). Cystatin C is a strong, independent risk factor for mortality in the elderly. Future studies should investigate whether cystatin C has a role in clinical medicine.

Aged↗
PubMed2005

Nontraumatic fracture risk with diabetes mellitus and impaired fasting glucose in older white and black adults: the health, aging, and body composition study.

BACKGROUND: Diabetes mellitus (DM) and related complications may increase clinical fracture risk in older adults. METHODS: Our objectives were to determine if type 2 diabetes mellitus or impaired fasting glucose was associated with higher fracture rates in older adults and to evaluate how diabetic individuals with fractures differed from those without fractures. The Health, Aging, and Body Composition Study participants were well-functioning, community-dwelling men and women aged 70 to 79 years (N = 2979; 42% black), of whom 19% had DM and 6% had impaired fasting glucose at baseline. Incident nontraumatic clinical fractures were verified by radiology reports for a mean +/- SD of 4.5 +/- 1.1 years. Cox proportional hazards regression models determined how DM and impaired fasting glucose affected subsequent risk of fracture. RESULTS: Diabetes mellitus was associated with elevated fracture risk (relative risk, 1.64; 95% confidence interval, 1.07-2.51) after adjustment for a hip bone mineral density (BMD) and fracture risk factors. Impaired fasting glucose was not significantly associated with fractures (relative risk, 1.34; 95% confidence interval, 0.67-2.67). Diabetic participants with fractures had lower hip BMD (0.818 g/cm(2) vs 0.967 g/cm(2); P<.001) and lean mass (44.3 kg vs 51.7 kg) and were more likely to have reduced peripheral sensation (35% vs 14%), transient ischemic attack/stroke (20% vs 8%), a lower physical performance battery score (5.0 vs 7.0), and falls (37% vs 21%) compared with diabetic participants without fractures (P<.05). CONCLUSIONS: These results indicate that older white and black adults with DM are at higher fracture risk compared with nondiabetic adults with a similar BMD since a higher risk of nontraumatic fractures was found after adjustment for hip BMD. Fracture prevention needs to target specific risk factors found in older adults with DM.

Black or African American↗
PubMed2005

Hearing sensitivity and bone mineral density in older adults: the Health, Aging and Body Composition Study.

Bone mineral density (BMD) may be associated with hearing loss in older adults. Demineralization of the cochlear capsule has been associated with hearing loss in those with Paget's disease of the bone and otosclerosis. Osteoporosis may also result in cochlear capsule demineralization. We hypothesized that lower hip BMD and lower heel ultrasound measurements would be associated with hearing loss in a population-based sample of 2,089 older black and white men and women. Bone parameters and hearing function were measured at the fourth clinical follow-up visit. Audiometric threshold testing was used to measure air- and bone-conduction hearing sensitivity. BMD of the hip and its subregions was measured using dual-energy X-ray absorptiometry. Calcaneal bone measurements [broadband ultrasound attenuation (BUA), speed of sound (SOS) and the quantitative ultrasound index (QUI)] were obtained using heel ultrasound. After adjusting for known hearing loss risk factors, no association was found between hearing and any of the bone measurements in whites and black women. In black men, however, lower hip BMD was associated with higher odds of hearing loss; for each standard deviation decrease in total hip BMD, the odds of hearing loss were 1.41 (95% confidence interval 1.08, 1.83), 1.39 (95% CI 1.07, 1.82) for femoral neck BMD and 1.65 (95% CI 1.26, 2.16) for trochanter BMD. Conductive hearing loss was associated with lower heel ultrasound measurements, though only among white men. The results of this study are mixed and inconclusive. Lower BMD of the hip and its subregions was associated with hearing loss among black men, but not among whites or black women. Lower measurements on heel ultrasound were associated with conductive hearing loss, though only among white men. These results suggest that axial and appendicular bone parameters may be modestly associated with hearing loss in older men, but not in women.

Absorptiometry, Photon↗
PubMed2005

Lower serum albumin concentration and change in muscle mass: the Health, Aging and Body Composition Study.

BACKGROUND: Low albumin concentrations in older persons increase the risk of poor health outcomes, including functional decline. OBJECTIVE: The aim of the study was to investigate the association between serum albumin concentration and skeletal muscle loss (sarcopenia) in old age. DESIGN: Serum albumin concentration was measured in 1882 black and white men and women aged 70-79 y participating in the Health, Aging and Body Composition Study. Five-year changes in appendicular skeletal muscle mass (ASMM), total-body fat-free mass (FFM), and trunk lean mass (TLM) were measured by using dual-energy X-ray absorptiometry. Confounders included health and lifestyle factors, which are markers of inflammation and protein intake. RESULTS: A low albumin concentration (< 38 g/L) was observed in 21.2% of the study participants. After adjustment for confounders, the mean (+/-SE) change in ASMM was -82 +/- 26 g per 3-g/L lower albumin concentration (P = 0.002). This association remained after persons with a low albumin concentration (< 38 g/L) were excluded. The decline in ASMM in subjects with low albumin concentrations was almost 30% higher (-930 +/- 56 g) than that in those with albumin concentrations > or = 42 g/L (-718 +/- 38 g; P < 0.01). The association between albumin and change in ASMM remained after additional adjustment for weight change. A weak association was observed for FFM, whereas no association was observed for TLM, which suggests a specific role of albumin in skeletal muscle change. CONCLUSIONS: Lower albumin concentrations, even above the clinical cutoff of 38 g/L, are associated with future loss of ASMM in older persons. Low albumin concentration may be a risk factor for sarcopenia.

Absorptiometry, Photon↗
PubMed2005

Dietary glycemic index and load, measures of glucose metabolism, and body fat distribution in older adults.

BACKGROUND: Recent evidence suggests that the rate of carbohydrate digestion and absorption may influence the development of type 2 diabetes. OBJECTIVE: The aim of this study was to examine associations of dietary glycemic index and glycemic load with predictors of type 2 diabetes in older adults. DESIGN: This study evaluated cross-sectional relations of dietary glycemic index and glycemic load with measures of glucose metabolism and body fat distribution in participants of the Health, Aging and Body Composition Study, a prospective cohort study of adults aged 70-80 y (n = 2248). RESULTS: In men, dietary glycemic index was positively associated with 2-h glucose (P for trend = 0.04) and fasting insulin (P for trend = 0.004), inversely associated with thigh intramuscular fat (P for trend = 0.02), and not significantly associated with fasting glucose, glycated hemoglobin, or visceral abdominal fat. Dietary glycemic load was inversely associated in men with visceral abdominal fat (P for trend = 0.02) and not significantly associated with fasting glucose, 2-h glucose, glycated hemoglobin, fasting insulin, or thigh intramuscular fat. In women, although dietary glycemic index and load were not significantly related to any measures of glucose metabolism or body fat distribution, the association between dietary glycemic index and 2-h glucose was nearly significant (P for trend = 0.06). CONCLUSION: The findings of this cross-sectional study indicate an association between dietary glycemic index and selected predictors of type 2 diabetes in older adults, particularly in men.

Adipose Tissue↗
PubMed2005

QDR 4500A dual-energy X-ray absorptiometer underestimates fat mass in comparison with criterion methods in adults.

BACKGROUND: Dual-energy X-ray absorptiometry (DXA) has become one of the most frequently used methods for estimating human body composition. Although the DXA technique has been validated for the measurement of fat-free mass and fat mass, differences in calibration between instruments produced by different manufacturers, as well as between different models produced by the same manufacturer, have been reported. OBJECTIVE: The objective was to compare the calibration of the QDR 4500A against criterion methods in a large heterogeneous population. DESIGN: DXA-derived body-composition data were obtained from 7 studies: 6 data sets were provided by the investigators, one of which was published. The data included fat mass and fat-free mass measured with a QDR 4500A and criteria measurements of body composition from total body water by dilution at 4 centers, densitometry from 1 center, and four-compartment analysis at 2 centers. RESULTS: In the cohort of 1195 subjects, 602 men and 593 women aged 19-82 y with a body mass index (in kg/m2) of 16-44, the fan-beam DXA overestimated fat-free mass (P < 0.05). A significant difference was observed in all 7 data sets, and the mean (+/-SE) was 5 +/- 1%. CONCLUSIONS: It is recommended that the lean soft tissue mass estimate with the fan-beam QDR 4500A be reduced by 5% and that for fat mass be increased by that same mass. This finding is particularly important because the National Health and Nutrition Examination Survey is using the QDR 4500A to assess body composition in a nationally representative sample of persons in the United States.

Absorptiometry, Photon↗
PubMed2005

Weight change and the conservation of lean mass in old age: the Health, Aging and Body Composition Study.

BACKGROUND: Weight loss may contribute to the loss of lean mass with age. OBJECTIVE: The objective was to evaluate the relation between weight loss or weight gain and changes in lean mass and fat mass in older adults. DESIGN: We observed changes in weight and body composition during a 4-y period in 2163 men (47%) and women (53%) aged 70-79 y in the Health, Aging and Body Composition Study cohort. Whole-body and appendicular bone-free lean mass and fat mass were measured by using dual-energy X-ray absorptiometry. RESULTS: Weight loss and weight gain were common. In both weight losers and weight gainers, changes in lean mass as a percentage of initial lean mass were substantially smaller than changes in fat mass as a percentage of initial fat mass. However, the difference between the change in lean mass and that in fat mass was more pronounced with weight gain than with weight loss, especially in men. Small amounts of lean loss and fat gain were noted with weight stability. In multivariate models, weight loss was strongly associated with lean mass loss in both men and women, especially in men whose weight loss was concurrent with a hospitalization. CONCLUSIONS: With weight change, a greater proportion of lean mass than of fat mass was conserved, but, especially in older men, significantly more lean mass was lost with weight loss than was gained with weight gain. These findings suggest that weight loss, even with regain, could accelerate sarcopenia in older adults.

Absorptiometry, Photon↗
PubMed2005

Trunk muscle composition as a predictor of reduced functional capacity in the health, aging and body composition study: the moderating role of back pain.

BACKGROUND: Cross-sectionally, lower trunk muscle attenuation (higher fat infiltration) has been associated with poorer physical function in older adults. We hypothesize that lower trunk muscle attenuation will be associated with lower functional capacity 3 years later and that back pain status will moderate this relationship. METHODS: The study sample consisted of a biracial cohort of well functioning men (739) and women (788) aged 70-79 years from the Pittsburgh site of the Health, Aging and Body Composition (Health ABC) study. Computed tomography was used to measure trunk muscle area and attenuation of the lumbar paraspinal, lateral abdominal, and rectus abdominus muscles at baseline. The Health ABC Physical Performance Battery (usual and narrow walk, chair stands, and standing balance) was used to measure functional capacity at the first and fourth annual clinic visits. RESULTS: Regardless of back pain status, average trunk muscle attenuation (but not muscle area) was positively associated with overall physical performance, particularly balance (p <.01), in a fully adjusted model. The association between trunk attenuation and functional capacity was significantly stronger in participants with at least moderate back pain in the year prior to baseline (p <.05 for interaction; attenuation x back pain). Participants with moderate to extreme back pain had a greater decline in function over time (p <.05). CONCLUSIONS: Older adults with poorer trunk muscle composition (higher fat infiltration) exhibit reduced functional capacity, especially balance, 3 years later. Improving trunk muscle composition may be an important yet overlooked approach to maintain function and potentially reduce balance impairments, particularly in persons with a history of back pain.

Aged↗
PubMed2005

Cross-sectional associations between trunk muscle composition, back pain, and physical function in the health, aging and body composition study.

BACKGROUND: Associations between trunk muscle composition and physical function have not been examined previously in older adults. We hypothesized that lower trunk muscle area and attenuation (higher fat infiltration) are associated with decreased functional capacity. METHODS: The study sample consisted of a biracial cohort of well functioning men (739) and women (788) aged 70-79 from the Pittsburgh site of the Health, Aging and Body Composition (Health ABC) study. Computed tomography was used to measure trunk muscle area (cm2) and muscle attenuation (Hounsfield Unit [HU]) of the following muscle groups: lumbar paraspinals, lateral abdominals, and rectus abdominis. An average score was calculated for both trunk area and attenuation. The Health ABC Physical Performance Battery (PPB) and its individual components (usual and narrow walk, chair stands, and standing balance) were used to measure functional capacity. RESULTS: Linear regression analyses adjusting for demographic factors, height, body fat, thigh muscle composition, disease status, and low back pain (LBP) found that average trunk muscle area was not associated with any element of functional capacity (p >.10), whereas average trunk muscle attenuation was positively associated with the Health ABC Physical Performance Battery (p <.05) and chair stands (p <.001). Participants reporting higher LBP severity during the past year had lower muscle attenuation (p <.001 for trend), but there was no difference in average trunk muscle area according to LBP status. CONCLUSIONS: Findings suggest a link between trunk muscle composition and history of LBP as well as reduced functional capacity in older adults. Improving trunk muscle quality may lead to reduced LBP severity and improved functional status.

Abdomen↗