Biomedical subjects

E J Metter

Publications and source records attributed to E J Metter.

At least 55 records · Page 3Linked to original sources

PubMed1998

The relationship of peripheral motor nerve conduction velocity to age-associated loss of grip strength.

Age-associated loss of muscle strength is attributed to decreasing muscle mass. Both strength and mass are dependent on peripheral innervation. However, the association between nerve function and age-associated strength loss has not been studied directly. The median nerve contribution to grip strength was estimated using nerve conduction velocity (NCV). Grip strength and NCV were measured in 197 male participants of the Baltimore Longitudinal Study of Aging (age 59.0 +/- 13.9 years). Multiple regression and path analyses were used separately to examine the association between median NCV and grip strength. Grip strength showed a negative quadratic relationship with increasing age (r2 = 0.32, p < 0.001) with a major change in slope occurring after 64.7 years of age. Median NCV (r2 = 0.14, p < 0.001) declined linearly with age. Median NCV significantly contributed to grip strength (p < 0.001) while controlling for forearm muscle mass (forearm circumference), self-reported 24-hour caloric expenditures, and age. The median nerve has an independent contribution to age-associated levels of muscle strength. The level of the effect was smaller than what could be attributed to forearm muscle mass or age.

Aged↗

PubMed1998

Blood-flow velocities and their relationships in carotid and middle cerebral arteries.

This study defines normative flow velocity (FV) ranges for the common carotid (CCA), internal carotid (ICA) and middle cerebral arteries (MCA), compares them to subjects with nonfocal vascular disease (mild to moderate hypertension, diabetes, hyperlipidemia or coronary artery disease), and clarifies the association between carotid and MCA FVs. FVs were measured by carotid and transcranial Doppler ultrasonography in 278 healthy and 190 vascular-disease subjects. Normative FV ranges for CCA, ICA and MCA were large in healthy subjects, with modest gender and age differences. Vascular-disease subjects had similar FVs to healthy controls. MCA FVs were significantly correlated with carotid FVs (r ranged 0.26-0.50), but were only weakly or not significantly associated with them (beta ranged 0.08-0.18) when controlling for age and gender. These findings suggest that normative FVs are not affected by the presence of nonfocal vascular disease, but carotid FVs do not aid in assessing MCA FVs.

Adult↗

PubMed1997

Decomposition-enhanced spike-triggered averaging: contraction level effects.

Decomposition-enhanced spike-triggered averaging (DE-STA) was applied to the vastus medialis muscle to examine size distributions of surface-detected motor-unit action potentials (S-MUAPs) at various force levels. Using DE-STA, 15-20 S-MUAPs were identified during 5%, 10%, 20%, and 30% of maximum voluntary contraction. Average S-MUAPs showed increase in peak to peak (and negative peak) amplitude with force (In microV): 5% = 37.9 +/- 6.1 (16.6 +/- 2.5), 10% = 44.0 +/- 4.0 (20.4 +/- 1.8), 20% = 80.7 +/- 9.3 (41.3 +/- 4.5), and 30% = 102.5 +/- 10.3 (53.6 +/- 5.0). Test-retest variability of peak to peak (and negative peak amplitude) between repeated trials was 0.10 (0.14), 0.14 (0.14), 0.17 (0.15), and 0.21 (0.20) at 5%, 10%, 20%, and 30% respectively. A relationship was found between the S-MUAP amplitude and force (r2 = 0.78, df = 90, F = 160, P < 0.001). Increase in average S-MUAP amplitude with force suggests that STA performed only at low levels of contraction may result in a biased sampling and small average S-MUAP amplitudes.

Action Potentials↗

PubMed1997

Percentage of free prostate-specific antigen in sera predicts aggressiveness of prostate cancer a decade before diagnosis.

OBJECTIVES: To evaluate serial measurements of free and total prostate-specific antigen (PSA) as a predictor of prostate cancer aggressiveness. METHODS: Twenty men diagnosed with adenocarcinoma of the prostate in the pre-PSA era had serum PSA measurements made on multiple stored frozen sera samples available for up to 18 years prior to diagnosis. Subjects were categorized as having aggressive cancer (n = 12) based on the presence of clinical Stage T3, or nodal or bone metastases (N+, M+), or pathologic positive-margin disease, or a Gleason score of 7 or greater; nonaggressive cancer (n = 8) was identified by the absence of these criteria. RESULTS: There was no statistically significant difference in free PSA levels among men with aggressive and nonaggressive prostate cancers from 0 to 15 years before diagnosis. Total PSA levels were significantly different between the groups by 5 years before diagnosis (P = 0.04). At a time when total PSA levels were not different between groups (10 years before diagnosis), there was a statistically significant difference in the percentage of free PSA between aggressive and nonaggressive cancers (P = 0.008). Among 14 men who had sera available for analysis at 10 years before diagnosis, all 8 men with aggressive cancers had a percent free PSA of 0.14 or less; this compares with only 2 of 6 men (33%) with nonaggressive cancer. CONCLUSIONS: These data suggest that the percentage of free PSA in sera is predictive of tumor behavior at a time when total PSA levels provide no information on tumor aggressiveness. Evaluation of the percentage of free serum PSA may be helpful in making the decision between expectant management and treatment for those men who are diagnosed with early prostate cancers by PSA testing.

Adenocarcinoma↗

PubMed1997

Age-associated loss of power and strength in the upper extremities in women and men.

Cross-sectional and longitudinal age-associated reductions in power and isometric strength are described for the upper extremities. Over a 25-year period, repeated measures were taken approximately every 2 years from men and women in the Baltimore Longitudinal Study of Aging (BLSA). The longitudinal measures covered an average 9.6 years, range 1-25 years for men and an average 4.6 years, range 1-8 years for women. Strength and power declined beginning by age 40 in both women and men. Thereafter, power declined about 10% more than strength in men, while no significant differences were found in women. Age had a statistically independent influence on strength and power measures after adjusting for gender, height, weight, caloric expenditure, and muscle mass. Twenty-five-year longitudinal analyses in men confirmed the declines observed cross-sectionally, while no changes were observed in women over the 4-5 years of longitudinal data available. Further longitudinal studies are needed to understand the relationships between strength and power losses with age in women. The differences between power and strength changes with age in men argue for the importance of factors other than strength affecting power.

Adult↗

PubMed1997

Age and gender comparisons of muscle strength in 654 women and men aged 20-93 yr.

To assess age and gender differences in muscle strength, isometric, concentric (Con), and eccentric (Ecc) peak torque was measured in the knee extensors at a slow (0.52 rad/s) and fast (3.14 rad/s) velocity in 654 subjects (346 men and 308 women, aged 20-93 yr) from the Baltimore Longitudinal Study of Aging. Regression analysis revealed significant (P < 0.001) age-related reductions in Con and Ecc peak torque for men and women at both velocities, but no differences were observed between the gender groups or velocities. Age explained losses in Con better than Ecc peak torque, accounting for 30% (Con) vs. 19% (Ecc) of the variance in men and 28% (Con) vs. 11% (Ecc) in women. To assess age and gender differences in the ability to store and utilize elastic energy, the stretch-shortening cycle was determined in a subset of subjects (n = 47). The older women (mean age = 70 yr) showed a significantly greater enhancement in the stretch-shortening cycle, compared with men of similar age (P < 0.01) and compared with younger men and women (each P < 0.05). Both men and women showed significant declines in muscle quality for Con peak torque (P < 0.01), but no gender differences were observed. Only the men showed a significant decline in muscle quality (P < 0.001) for Ecc peak torque. Thus both men and women experience age-related losses in isometric, Con, and Ecc knee extensor peak torque; however, age accounted for less of the variance in Ecc peak torque in women, and women tend to better preserve muscle quality with age for Ecc peak torque. In addition, older women have an enhanced capacity to store and utilize elastic energy compared with similarly aged men as well as with younger women and men.

Adult↗

PubMed1997

Risk of Alzheimer's disease and duration of NSAID use.

In a longitudinal study of 1,686 participants in the Baltimore Longitudinal Study of Aging, we examined whether the risk of Alzheimer's disease (AD) was reduced among reported users of aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs). In addition, we examined use of acetaminophen, a pain-relief medication with little or no anti-inflammatory activity, to assess the specificity of the association between AD risk and self-reported medications. Information on use of medications was collected during each biennial examination between 1980 and 1995. The relative risk (RR) for AD decreased with increasing duration of NSAID use. Among those with 2 or more years of reported NSAID use, the RR was 0.40 (95% confidence interval [CI]: 0.19-0.84) compared with 0.65 (95% CI: 0.33-1.29) for those with less than 2 years of NSAID use. The overall RR for AD among aspirin users was 0.74 (95% CI: 0.46-1.18), and no trend of decreasing risk of AD was observed with increasing duration of aspirin use. No association was found between AD risk and use of acetaminophen (RR = 1.35; 95% CI: 0.79-2.30), and there was no trend of decreasing risk with increasing duration of use. These findings are consistent with evidence from cross-sectional studies indicating protection against AD risk among NSAID users and with evidence suggesting that one stage of the pathophysiology leading to AD is characterized by an inflammatory process.

Acetaminophen↗

PubMed1997

Estrogen replacement therapy and longitudinal decline in visual memory. A possible protective effect?

Estrogen replacement therapy (ERT) is increasingly recommended for postmenopausal women due to its beneficial effects on physical health in older women. Recent studies have suggested that ERT may have a protective effect on cognitive function and may reduce the risk of Alzheimer's disease. In the present study we test the hypothesis that ERT may have a protective effect on memory in nondemented women. Data on hormonal status and memory were examined in 288 postmenopausal women in the Baltimore Longitudinal Study of Aging. One hundred sixteen women who reported that they were receiving ERT during a cognitive assessment were compared with 172 women who had never received ERT. Women who were receiving ERT had fewer errors on the Benton Visual Retention Test (BVRT), a measure of short-term visual memory, visual perception, and constructional skills. Furthermore, ERT appeared to protect against age changes in BVRT performance in a subgroup of 18 women for whom BVRT data were available before and during treatment with ERT. These findings suggest that ERT may protect against memory decline in nondemented postmenopausal women and offer further support for a beneficial role of estrogen on cognitive function in aging women.

Aged↗

PubMed1997

The effect of threshold amounts for reporting malpractice payments to the National Practitioner Data Bank: analysis using the closed claims data base of the Office of the Assistant Secretary of Defense (Health Affairs).

The study determines the extent to which payment thresholds for reporting malpractice claims to the National Practitioner Data Bank identifies substandard health care delivery in the Department of Defense. Relevant data were available on 2,291 of 2,576 medical malpractice claims reported to the closed medical malpractice case data base of the Office of the Assistant Secretary of Defense (Health Affairs). Amount paid was analyzed as a diagnostic test using standard of care assessment from each military Surgeon General office as the criterion. Using different paid threshold amounts per claim as a positive test, the sensitivity of identifying substandard care declined from 0.69 for all paid cases to 0.41 for claims over $40,000. Specificity increased from 0.75 for all paid claims to 0.89 for claims over $40,000. Positive and negative predictive values and likelihood ratio were similar at all thresholds. Malpractice case payment was of limited value for identifying substandard medical practice. All paid claims missed about 30% of substandard care, and reported about 25% of acceptable medical practice.

Government Agencies↗

PubMed1996

Longitudinal analysis of serial measurements of free and total PSA among men with and without prostatic cancer.

OBJECTIVES: Evaluation of free and total serum prostate specific antigen (PSA) levels before diagnosis of prostate cancer. METHODS: Free and total PSA levels were measured on frozen sera samples of 26 men with no history of prostate disease (controls), 29 men with a histologic diagnosis of benign prostatic hyperplasia (BPH) made at simple prostatectomy (BPH cases), and 23 men with a histologic diagnosis of prostatic cancer (cancer cases). Longitudinal regression analysis was used to evaluate PSA levels as a function of years before diagnosis of prostate disease. RESULTS: On average, mean total serum PSA was statistically significantly greater for subjects with cancer (5.0 ng/mL +/- 0.9) versus BPH (2.8 ng/mL +/- 0.3) and control subjects (0.8 ng/mL +/- 0.1) by 4 years before diagnosis, whereas free PSA levels were similar among groups at 4 years before diagnosis. The ratio of free to total serum PSA continuously decreased among cancer cases over the decade before cancer diagnosis. At a time when mean total and free PSA levels were similar among groups (8 years before diagnosis), the ratio of free to total PSA was statistically significantly lower for cancer cases (0.13 +/- 0.01) compared with BPH (0.17 +/- 0.01) and control cases (0.21 +/- 0.02). Use of a free to total PSA ratio of < or = 0.12 when total PSA was between 4.0 and 10.0 ng/mL resulted in the highest sensitivity (76%) and specificity (94%) for diagnosis among subjects with and without cancer. Lowering the reflex range to 2.5 ng/mL increased false positive tests more than it increased sensitivity. CONCLUSIONS: The ratio of free to total PSA is the earliest serum marker predicting a subsequent diagnosis of prostate cancer. Measurement of the free to total serum PSA ratio would appear to reduce false positive results among men without prostate cancer.

Aged↗

PubMed1996

Longitudinal changes in smell identification.

BACKGROUND: Cross-sectional studies have demonstrated that olfactory function diminishes with increasing age, which may impact on the safety and quality of life of older persons. To date, however, there have been no published longitudinal studies on olfaction. The purpose of this study was to examine the influence of age and gender on smell identification over a 3-year period in a group of generally healthy men and women. METHODS: Males (n = 85) and females (n = 76) between the ages of 19 and 95 years were administered the University of Pennsylvania Smell Identification Test (SIT) over a 3-year span as part of the oral physiology component of the Baltimore Longitudinal Study of Aging. A linear mixed-effects regression model was used to determine how longitudinal changes in SIT scores differ with respect to gender, history of medical problems, and use of prescription medications. RESULTS: Over the 3-year period, SIT scores diminished progressively with increased age. Women and men in the eighth decade of life experienced a decline of greater than one SIT point per year. Females consistently performed better than males in smell identification. Similar results were obtained regardless of medical problems or medication usage. CONCLUSIONS: These results extend the conclusions of previous cross-sectional olfactory studies and indicate that smell identification deteriorates progressively with greater age. Furthermore, age-related declines in olfaction occur even in the absence of overt medical problems.

Adult↗

PubMed1996

Risk factors related to age-associated hearing loss in the speech frequencies.

This paper examines the relationship between several risk factors and the development of age-associated hearing loss in the speech frequencies. Hearing loss is defined as an average threshold level of 30 dB HL or greater at the frequencies of 0.5, 1, 2, and 3 kHz. Hearing thresholds from 0.5 to 8 kHz using a pulse-tone tracking procedure were collected on participants of the Baltimore Longitudinal study of Aging since 1965. A proportional hazards regression model was used to study the relationship between several risk factors that have previously been found to be associated with numerous health-related outcomes and the length of follow-up time until the occurrence of unilateral or bilateral hearing loss in a screened group of 531 men. Risk factors considered are age, blood pressure, and alcohol and cigarette consumption. After controlling for age, only systolic blood pressure showed a significant relationship with hearing loss in the speech frequencies (p < .05). Since blood pressure is a modifiable risk factor, these results suggest that preventing hypertension might contribute to an effective program for the prevention of apparent age-associated hearing loss.

Adult↗

PubMed1995

Longitudinal evaluation of serum androgen levels in men with and without prostate cancer.

Androgens are thought to play a role in the pathogenesis of prostate cancer. We evaluated androgen levels in 3 age-matched groups of men who were part of the Baltimore Longitudinal Study of Aging: 1) 16 men with no prostatic disease by urologic history and exam (control group); 2) 20 men with a histologic diagnosis of benign prostatic hyperplasia (BPH) who had undergone simple prostatectomy; and 3) 20 men with a histologic diagnosis of prostate cancer (16 with local/regional cancer, and 4 with metastatic cancer). Luteinizing hormone (LH), total testosterone (T), and free T were measured on stored AM sera by radioimmunoassay (RIA). Free T was also calculated from the measured concentrations of total T and sex hormone binding globulin (SHBG). The median number of repeated sex steroid measurements ranged from 6-9 over a period from 7-25 years prior to the diagnosis of prostate disease. There were no significant differences in age-adjusted LH, total T, SHBG, or calculated free T levels among the groups at 0-5, 5-10, and 10-15 years before diagnosis. These data suggest that there are no measurable differences in serum testosterone levels among men who are destined to develop prostate cancer and those without the disease.

Age Factors↗

PubMed1995

Prostate-specific antigen variability in men without prostate cancer: effect of sampling interval on prostate-specific antigen velocity.

OBJECTIVES: To evaluate short-term and long-term variability between prostate-specific antigen (PSA) measurements to determine the most appropriate PSA sampling interval and rate of PSA change (PSA velocity) to distinguish between men with and without prostate cancer. METHODS: Retrospective study of PSA variability and PSA velocity in three groups of men without a diagnosis of prostate cancer and PSA levels less than 10 ng/mL: 56 men with a histologic diagnosis of benign prostatic hyperplasia (BPH; histologic BPH group) and 527 men with no history of cancer (noncancer group) who were part of the Baltimore Longitudinal Study of Aging and had PSA sampled at 2-year intervals (long-term), and 223 men with a clinical diagnosis of BPH (clinical BPH group) who had PSA sampled at 3-month intervals (short-term). PSA variability (deviation between consecutive measurements) and PSA velocity based on both two consecutive measurements and three consecutive measurements (average velocity) were calculated for each study group. RESULTS: PSA velocity is the deviation in PSA measurements relative to the elapsed time between the measurements. Because the variability in PSA between measurements was similar for the groups, the major factors that influenced PSA velocity were the sampling interval between PSA measurements, and to a lesser extent, the number of repeat PSA measurements. The 99th percentile for PSA velocity was 0.7 (histologic BPH group) and 0.75 ng/mL per year for the noncancer group when three measurements with a 24-month PSA sampling interval were used. However, the 99th percentile for PSA velocity was 5.8 and 2.4 ng/mL per year when three measurements with 3-month and 6-month PSA sampling intervals were used. Using three measurements, the percentage of subjects with a PSA velocity more than 0.75 ng/mL per year was 1% for the groups with a 24-month PSA sampling interval and 28% and 17% for 3-month and 6-month PSA sampling intervals, respectively. The 99th percentile for PSA velocity and the percentage of subjects with a PSA velocity more than 0.75 ng/mL per year was higher using two measurements compared to three measurements regardless of PSA sampling interval. CONCLUSIONS: PSA velocity is inversely related to the interval between PSA measurements. A PSA velocity more than 0.75 ng/mL per year is useful in distinguishing between men with and without prostate cancer when: (1) velocity is based on three consecutive measurements; and (2) PSA is sampled long-term (2 years) but not short-term (3 to 6 months).

Aged↗

PubMed1995

Gender differences in a longitudinal study of age-associated hearing loss.

Current studies are inconclusive regarding specific patterns of gender differences in age-associated hearing loss. This paper presents results from the largest and longest longitudinal study reported to date of changes in pure-tone hearing thresholds in men and women screened for otological disorders and noise-induced hearing loss. Since 1965, the Baltimore Longitudinal Study of Aging has collected hearing thresholds from 500 to 8000 Hz using a pulsed-tone tracking procedure. Mixed-effects regression models were used to estimate longitudinal patterns of change in hearing thresholds in 681 men and 416 women with no evidence of otological disease, unilateral hearing loss, or noise-induced hearing loss. The results show (1) hearing sensitivity declines more than twice as fast in men as in women at most ages and frequencies, (2) longitudinal declines in hearing sensitivity are detectable at all frequencies among men by age 30, but the age of onset of decline is later in women at most frequencies and varies by frequency in women, (3) women have more sensitive hearing than men at frequencies above 1000 Hz but men have more sensitive hearing than women at lower frequencies, (4) learning effects bias cross-sectional and short-term longitudinal studies, and (5) hearing levels and longitudinal patterns of change are highly variable, even in this highly selected group. These longitudinal findings document gender differences in hearing levels and show that age-associated hearing loss occurs even in a group with relatively low-noise occupations and with no evidence of noise-induced hearing loss.

Adult↗

PubMed1995

Rapid decline in FEV1. A new risk factor for coronary heart disease mortality.

Coronary heart disease (CHD) is the leading cause of mortality in the United States. The present cohort study was conducted to determine whether rate of FEV1 loss independently predicts CHD mortality in apparently healthy men. White male Baltimore Longitudinal Study of Aging (BLSA) participants without CHD underwent clinical evaluation at 2-yr intervals; 883 had satisfactory pulmonary and lipid studies and returned for a least one visit. Cases were BLSA subjects without CHD on entry who died a "coronary death" (death from acute myocardial infarction, sudden death, or congestive heart failure in the presence of coronary artery disease). Forced expiratory maneuvers followed American Thoracic Society guidelines. Serum cholesterol, blood pressure, cigarette smoking, and body mass index were obtained from the BLSA database. There were 79 CHD deaths and 804 survivors during an average follow-up of 17.4 yr. After adjustment for age, initial FEV1% predicted, smoking status, hypertension, and cholesterol, a time-dependent proportional hazards model showed that cardiac mortality, but not all causes of mortality, generally increased with increasing quintile of FEV1 decline for the entire cohort (relative risk [RR] 2.92-5.13) and separately for the subset of never-smokers. Thus, excess CHD mortality follows a large decline in FEV1, independent of the initial FEV1% predicted, cigarette smoking, and other common CHD risk factors.

Adolescent↗

PubMed1992

Estimation of prostatic growth using serial prostate-specific antigen measurements in men with and without prostate disease.

Prostate growth curves were estimated from serial prostate-specific antigen (PSA) measurements on frozen sera in three groups of men: (a) 16 men with no prostatic disease by urological history and examination; (b) 20 men with a histological diagnosis of benign prostatic hyperplasia (BPH) who had undergone simple prostatectomy; and (c) 18 men with a histological diagnosis of prostate cancer. The median number of repeated PSA measurements over an 8- to 26-yr period prior to histological diagnosis or exclusion of prostate disease was eight and 11 for noncancer and cancer subjects, respectively. Predicted rates of change in PSA (PSA velocity) were linear and curvilinear for control and BPH subjects, respectively. Subjects with cancer demonstrated both a linear and an exponential phase of PSA velocity. Based on time to double PSA, we estimated the epithelial doubling time for men without prostate disease to range from 54 +/- 13 yr at age 40 to 84 +/- 13 yr at age 70. For men with BPH, doubling times ranged from 2 +/- 13 yr at age 40 to 17 +/- 5 yr at age 85. Subjects with local/regional and advanced/metastatic cancer had similar PSA doubling times of 2.4 +/- 0.6 yr and 1.8 +/- 0.2 yr, respectively. These data are consistent with what is known about prostatic growth with age in men without prostate disease and BPH, and the kinetics of prostate cancer growth. Estimates of prostatic growth rate from changes in PSA may be useful clinically in management of men with prostate disease.

Aged↗

PubMed1992

Response stability and reliability in longitudinal health evaluations.

Two approaches were used to study the stability over time and intravisit reliability of health questions and clinical medical examination items in the Baltimore Longitudinal Study of Aging (BLSA). The stability of responses was determined by evaluating the medical history and physical examination completed at each visit to identify items that once answered in a positive manner, should continue to be answered positively over time. Stability for each question and subject was calculated by the number of positive responses following the first positive response divided by the total number of visits following the first positive response. For 35 questions answered by the subject, the stability was 58% by a simple average or 64% when weighted for the percentage of subjects who had a positive response to the question; for 10 physician-asked questions, the corresponding figures were 29% or 36%. Eighteen items from the physical examination had a stability of 34% or 37%. Intravisit reliability was estimated by comparing responses from the general health questionnaire to responses on the Cornell Medical Index completed at the same visit. Subject-completed questions had substantial agreement (Kappa = 0.74, for questions worded the same), while physician-asked questions had moderate agreement (Kappa = 0.44).

Adult↗