Biomedical subjects

Stefano Volpato

Publications and source records attributed to Stefano Volpato.

41 records · Page 3Linked to original sources

PubMed2002

Reliability and sensitivity to change assessed for a summary measure of lower body function: results from the Women's Health and Aging Study.

A summary performance measure comprised of a hierarchical balance task, a 4-meter walk, and five repetitive chair stands is increasingly being used as a predictor of independent living for older persons. The reliability and sensitivity to change of this summary performance measure have not been investigated, however. Because a measure can be reliable while being unresponsive to change, this study presents information on both the reliability and sensitivity to change for the summary performance measure. This is a 3-year prospective cohort study of 1,002 moderately to severely disabled older women. Short- and long-term reliability was assessed by intraclass correlation coefficients (ICC). Sensitivity to change was assessed by slope differences for three age categories (65-74, 75-84, and >or=85) over six 6-month follow-up periods. Sensitivity to change was also assessed by summary performance change scores for those who did and did not suffer from one of four medical events [myocardial infarction (MI), stroke, hip fracture, or congestive heart failure (CHF)] at follow-up. The summary performance measure showed excellent reliability. Intraclass correlation coefficients ranged from 0.88 to 0.92 for measures made 1 week apart. The 6-month average intraclass correlation coefficient was 0.77 (range 0.72-0.79). The summary performance measure was also highly responsive to change. Subjects who suffered an incident MI, stroke, hip fracture, or CHF at follow-up were significantly more likely to have poorer summary performance change scores (-2.25) compared with those who did not have one of these medical events (-0.24). Additionally, subjects who suffered one of these events improved their summary performance scores in the following assessment period by 0.72. With increasing utilization of the summary performance measure by researchers and clinicians it is important that the measurement properties of this instrument are known. Our results show that the summary performance measure has excellent reliability and is highly sensitive to change.

Activities of Daily Living↗

PubMed2002

Low serum vitamin d does not predict new disability or loss of muscle strength in older women.

OBJECTIVES: To determine whether serum levels of 25-hydroxyvitamin D (25(OH)D) and parathyroid hormone (PTH) predict accelerated decline in muscular strength or onset of new disability in mobility and upper extremity functioning over a 3-year follow-up. DESIGN: A community-based prospective cohort study. PARTICIPANTS: Six hundred twenty-eight moderately to severely disabled women aged 65 and older living in the community. MEASUREMENTS: Subjects were divided into three groups of baseline 25(OH)D serum levels (deficiency: <25 nmol/L; low normal: 25-52 nmol/L; high normal: > or =53 nmol/L) and into tertiles of PTH levels. Objective performance measures (hip flexor, knee extensor, and grip strengths; walking speed; and time for repeated chair stands) and disability in activities involving mobility and upper extremity function were assessed at baseline and every 6 months for 3 years. Decline in performance measures and onset of new disability were compared between 25(OH)D and PTH groups using random effects models and proportional hazards models, respectively, while adjusting for age, race, education, body mass index, baseline performance, and chronic conditions. RESULTS: The annual rate of decline over 3 years in muscular strength, walking speed, and time to perform repeated chair stands was similar across 25(OH)D groups. We observed a nonsignificantly faster decline in proximal muscle strength and walking speed with increasing PTH levels. There was no association for either measure between serum levels and the risk of incident disability in activities relating to mobility and upper extremity function. CONCLUSION: This study does not support the hypothesis that vitamin D deficiency is associated with loss in muscular strength and decline in mobility and upper extremity functioning over time in older women who were moderately to severely disabled at baseline.

Age Factors↗

PubMed2002

Change in muscle strength explains accelerated decline of physical function in older women with high interleukin-6 serum levels.

OBJECTIVES: To test whether accelerated sarcopenia in older persons with high interleukin (IL)-6 serum levels plays a role in the prospective association between inflammation and disability found in many studies. DESIGN: Cohort study of older women with moderate to severe disability. PARTICIPANTS: Six hundred twenty older women from the Women's Health and Aging Study in whom information on baseline IL-6 serum level was available. MEASUREMENTS: Self-report of functional status, objective measures of walking performance, and knee extensor strength were assessed at baseline and over six semiannual follow-up visits. Potential confounders were baseline age, race, body mass index, smoking, depression, and medical conditions. RESULTS: At baseline, women with high IL-6 were more often disabled and had lower walking speed. After adjusting for confounders, women in the highest IL-6 tertile (IL-6>3.10 pg/mL) were at higher risk of developing incident mobility disability (risk ratio (RR) = 1.50, 95% confidence interval (CI) = 1.01-2.27), disability in activities of daily living (RR = 1.41, 95% CI = 1.01-1.98), and severe limitation in walking (RR = 1.61, 95% CI = 1.09-2.38) and experienced steeper declines in walking speed (P <.001) than women in the lowest IL-6 tertile (IL-6 < or =1.78 pg/mL). Decline in knee extensor strength was also steeper, but differences across IL-6 tertiles were not significant. After adjusting for change over time in knee extensor strength, the association between high IL-6 and accelerated decline of physical function was no longer statistically significant. CONCLUSIONS: Older women with high IL-6 serum levels have a higher risk of developing physical disability and experience a steeper decline in walking ability than those with lower levels, which are partially explained by a parallel decline in muscle strength.

Activities of Daily Living↗

PubMed2002

Genetic factors associated with the absence of atherosclerosis in octogenarians.

BACKGROUND: Atherosclerosis (ATS) is a common age-related disease of large arteries. The prevalence of older subjects with vascular successful aging (VaSA), defined as the absence of clinical symptoms and instrumental signs of ATS, is low in Western countries. The possible contribution of genetics to the VaSA phenomenon is not known. METHODS: We investigated the distribution of four genetic polymorphisms (angiotensin converting enzyme [ACE], methylenetetrahydrofolate reductase [MTHFR], apolipoprotein E [apo E], and paraoxonase [PON] genes) in 30 subjects with VaSA, 30 subjects with moderate carotid atherosclerosis (ATS group), and 161 controls with a negative history for cardiovascular disease. Clinical examination; ultrasonographic examination of carotid, vertebral, abdominal aortic, iliac, and femoral arteries; and electrocardiogram were performed. RESULTS: The frequency of PON 192 B allele was lower in VaSA patients (13%) compared with ATS patients (37%) and controls (46%) ( p =.06 and.006, respectively); B/B homozygotes were 27% in the ATS group, 12% in controls, and 0% in the VaSA group. The frequency of the MTHFR thermolable + allele was higher in VaSA (0.51) compared with ATS (0.39) and controls (0.40) (VaSA vs C, p =.006). No differences in the distribution of ACE I/D and apo E alleles emerged between the three groups. CONCLUSIONS: The low prevalence of the PON 192 B allele in the VaSA subjects suggests that this polymorphism might have an important role in VaSA, probably by hydrolyzing lipid peroxides and thus preventing low-density lipoprotein from undergoing the oxidative modification. This finding further supports the oxidative hypothesis of ATS.

Aged↗

PubMed2002

Comorbidities and impairments explaining the association between diabetes and lower extremity disability: The Women's Health and Aging Study.

OBJECTIVE: To elucidate the role of diabetes-related impairments and comorbidities in the association between diabetes and physical disability, this study examined the association between diabetes and lower extremity function in a sample of disabled older women. RESEARCH DESIGN AND METHODS: Cross-sectional analysis of 1,002 women (aged >or=65 years) enrolled in the Women's Health and Aging Study (one-third most disabled of the total community-dwelling population). Diabetes and other medical conditions were ascertained by standard criteria that used multiple sources of information. Functional status was assessed using self-reported and objective performance measures. RESULTS: Women with diabetes were significantly more likely to have cardiovascular diseases, peripheral nerve dysfunction, visual impairment, obesity, and depression. After adjustment for age, women with diabetes had a greater prevalence of mobility disability (odds ratio [OR] 1.85, 95% CI 1.12-3.06), activities of daily living disability (1.61, 1.06-2.43), and severe walking limitation (2.34, 1.56-3.50), and their summary mobility performance score (0-12 scale based on balance, gait speed, chair stands) was 1.4 points lower than in nondiabetic women (P < 0.001). Peripheral artery disease, peripheral nerve dysfunction, and depression were the main individual contributing factors; however, none of these conditions alone fully explained the association between diabetes and disability. Conversely, only after adjusting for all potential mediators was the relationship between diabetes and disability reduced to a large degree. CONCLUSIONS: Even among physically impaired older women, diabetes is associated with a major burden of disability. A wide range of impairments and comorbidities explains the diabetes-disability relationship, suggesting that the mechanism for such an association is multifactorial.

Age of Onset↗