Biomedical subjects

J L Fozard

Publications and source records attributed to J L Fozard.

At least 37 records · Page 2Linked to original sources

PubMed1996

Age- and gender-specific reference ranges for hearing level and longitudinal changes in hearing level.

This paper presents age-specific reference ranges for hearing level and change in hearing level for men and women at 500, 1000, 2000, and 4000 Hz. The percentiles are constructed from data obtained from persons in the Baltimore Longitudinal Study of Aging who were rigorously screened for otological disorders and evidence of noise-induced hearing loss. The resulting percentile curves represent norms for changes in hearing level in the absence of any known otologic disease. These percentile curves provide a reference for detecting when a person deviates from a normal pattern of change, thus helping in diagnosing problems with hearing or in monitoring hearing in occupational settings. The smoothed means and standard deviations of the hearing levels were used to construct the longitudinal percentiles. The percentiles for cross-sectional change were constructed using the skew normal distribution to allow for the percentiles to be asymmetric on either side of the median level. These percentiles are the first reference curves that (1) provide standards for hearing level changes over periods of up to 15 years, (2) account for age differences in the distribution of hearing levels, and (3) are based on data from persons who have been systematically screened for otological disorders and evidence of noise-induced hearing loss.

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

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↗

PubMed1994

Age differences and changes in reaction time: the Baltimore Longitudinal Study of Aging.

This study analyzed auditory reaction time (RT) data from 1,265 community-dwelling volunteers (833 males and 432 females) who ranged in age from 17 to 96. Cross-sectional analyses revealed slowing of simple (SRT) and relatively greater slowing of disjunctive (DRT; aka "go-no-go") reaction time across decades for both males and females. Repeated testing within participants (longitudinal analyses) over eight years showed consistent slowing and increased variability with age. Males were faster than females cross age groups, RT tasks, and visits. Beginning at about age 20, RTs increased at a rate of approximately 0.5 msec/yr for SRT and 1.6 msec/yr for DRT. Errors also increased, making unlikely a tradeoff of accuracy for faster responses. The findings are consistent with the hypotheses that slowing of behavior is: (a) a continuous process over the adult life span; (b) characterized by age-associated increases in within-participant variability; (c) a direct function of task complexity and, presumably, the degree of mediation by higher regions in the central nervous system; and (d) greater in women than men.

Acoustic Stimulation↗

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↗

PubMed1992

Vision, aging, and driving: the problems of older drivers.

Although there are well-recognized declines in visual functioning with age, their contribution to the problems of older persons on tasks in the natural environment, including driving, are largely unknown. Adults ranging in age from 22-92 years were surveyed in regard to their visual difficulties when driving and performing everyday tasks. The visual problems of drivers increased with age along five different visual dimensions: unexpected vehicles, vehicle speed, dim displays, windshield problems, and sign reading. Several of the age-related visual problems that were reported appear to be related to the types of automobile accidents more common among older drivers. The study also replicated the findings from an earlier investigation of non-driving tasks that showed visual declines with age on five dimensions: visual processing speed, light sensitivity, dynamic vision, near vision and visual search. These findings indicate promising areas of research regarding the effects of visual aging on tasks in the natural environment.

Adult↗

PubMed1992

How comparable are healthy 60- and 80-year-old men?

A critical issue in cross-sectional aging studies is the comparability of subjects of different ages, particularly regarding health status. For example, it is typically assumed that healthy 60-year-old men are equivalent to healthy 80-year-old men when both age groups are selected using the same criteria. The 60-year-old, however, may not survive or be healthy at age 80. To examine this issue, 212 healthy 60-year-old men in the Baltimore Longitudinal Study of Aging were identified. By life table analysis, 30% were expected to survive and remain healthy to age 80. In this study, 61 healthy 60-year-old men were followed to age 80. When compared with 125 healthy 80-year-old men, they had more heart disease, cancer, stroke, arterial, digestive, and peripheral nervous system diseases. Twenty-seven of the 61 men (44%) actually continued to be healthy at age 80. At age 60, systolic pressure and total serum cholesterol were predictive of who would be healthy at age 80.

Age Factors↗

PubMed1991

Effect of age of entry to a longitudinal study on cross-sectional determination of cardiovascular disease.

Cross-sectional analysis from longitudinal studies for a specific age can include subjects who entered the study at different ages (i.e. younger individuals followed to the age of interest, and those who entered at the age of interest). This represents a potential source of bias, since the state of health at a given age may vary based on age at entry. We investigated such bias as it affected the prevalence of cardiovascular diagnoses in men from the Baltimore Longitudinal Study of Aging. Subjects who entered the study in either their 60's, 70's or 80's (New subjects) were compared to individuals who entered the study at an age at least 10 years younger and were followed into these same age decades (Continuing subjects). No differences were found between New and Continuing subjects for coronary heart or cerebrovascular diseases, but were present for hypertension. The greater prevalence of hypertension in Continuing subjects appeared to be of minor clinical importance because other diagnostic differences were absent. The study found evidence for potential selection bias based on age at entry, but the consequence of the bias appeared to be slight.

Age Factors↗

PubMed1990

Symptoms and signs of prostatism as risk factors for prostatectomy.

Symptom questionnaires and physical examinations administered periodically to 1,057 men followed prospectively for up to 30 years in the Baltimore Longitudinal Study of Aging (BLSA) were analyzed to determine which symptoms of prostatism were predictive of subsequent prostatectomy for benign prostatic hyperplasia (BPH). Change in the size and force of the urinary stream (P = 0.0001) and a sensation of incomplete emptying (P = 0.0005) were the only symptoms positively predictive in a multivariate analysis. Prostate enlargement by rectal palpation was an independent risk factor for prostatectomy (P less than 0.03) and was associated with hesitancy (P less than 0.02) and a sensation of incomplete emptying (P less than 0.02). Of the men with all three risk factors, 37% (41/112) eventually had a prostatectomy, in contrast to 8% of the remaining 945 men. This is the first study to document the extent to which urologic symptoms and a digital rectal examination predict subsequent prostatectomy for BPH.

Adolescent↗

PubMed1990

Cumulative prevalence of prostatism matches the autopsy prevalence of benign prostatic hyperplasia.

The age-specific cumulative prevalence of clinically diagnosed prostatism among 1,057 generally healthy men followed for up to 30 years in the Baltimore Longitudinal Study of Aging was compared with the age-specific autopsy prevalence of pathologically defined benign prostatic hyperplasia (BPH) from a published compilation of five independent autopsy studies involving 1,075 prostates. Clinical prevalences based on medical histories and digital rectal examinations showed excellent agreement with autopsy prevalences at all ages. Despite the well-known lack of correspondence between prostatism and objective urologic evidence of BPH in individual patients, these results suggest that the proportion of the male population with clinically recognizable prostatism by a given age is about the same as the proportion with pathological evidence of BPH.

Adult↗

PubMed1990

Next steps in describing aging and disease in longitudinal studies.

Longitudinal studies have contributed much to the understanding of aging. Traditionally, age-specific changes in physiological functioning are inferred from studies in which persons with disease processes believed to be relevant to the function in question are excluded from the results. The main theme of this review is that, in the future, studies of aging must better attempt to capture the interplay between disease and aging processes. A variety of research results, mostly from the Baltimore Longitudinal Study of Aging, are used to support this argument. Topics covered include: the role of longitudinal studies in aging research; the complexity of the aging process; the significance of cohort and secular changes for understanding both aging and disease processes; age changes over the adult life span in the significance of risk factors for disease; and age-related increases in morbidity in a longevous group of men.

Aging↗

PubMed1990

Age changes in pure-tone hearing thresholds in a longitudinal study of normal human aging.

Hearing thresholds were obtained on 813 adult males (20-95 years) measured at 11 frequencies ranging from 0.125-8 kHz from pure-tone audiograms collected over a 20-year period from 1968 to 1987. Audiograms taken at two to six different ages spanning a maximum observation period of 15 years were obtained for each male belonging to one of seven different age groups (20,30,...,80 years) based on the age of initial observation. The males were participants in the Baltimore Longitudinal study of Aging (BLSA), a multidisciplinary community-based study of normal human aging. Changes in hearing thresholds occurred in all age groups during the 15-year follow-up period. For example, at 0.5 and 8 kHz for combined left and right ears there was an average longitudinal loss of 5.7-7.6 and 5.1-21.1 dB, respectively, for 20-year-olds, 10.0-12.7 and 35.2-53.0 dB for 50-year-olds, and 22.9-48.5 and 69.0-84.5 dB for 80-year-olds. As in results from previous cross-sectional studies, hearing loss in the males 70 years and older is greatest at the highest frequencies. The rate of change for these older males is faster in the speech-range frequencies 0.5-2 kHz than in the higher frequencies, since their hearing has already diminished at the high frequencies.

Adult↗

PubMed1990

A longitudinal study of the relationship between intraocular and blood pressures.

The relationship between intraocular and systemic blood pressures was investigated in a prospective study of 572 middle-aged men. There was no consistent relationship between intraocular pressure at first visit and age. Subjects with an intraocular pressure greater than 20 mm Hg had a significantly higher systolic blood pressure than controls matched for age. An autoregressive model was used to examine the relationship between change in intraocular pressure and initial intraocular pressure, age, and blood pressure. When the authors compared data obtained 1 or 2 years apart, a change in intraocular pressure was positively correlated with a change in systolic blood pressure. Thus, the results of this study indicate that changes in intraocular pressure over time are associated with changes in systolic blood pressure and that intraocular pressure does not necessarily increase with age.

Adult↗

PubMed1986

Age related changes in visual acuity.

Longitudinal visual acuity assessments of men, and cross-sectional assessments of men and women in the Baltimore Longitudinal Study of Aging are presented. The longitudinal data relate presenting far, uncorrected far, presenting near and uncorrected near visual acuities to age. The cross-sectional data relate presenting far acuity to age. The prevalence of cataract, glaucoma and retinal pathologies are reported for the longitudinal sample at the time of their last vision test. The effect of visual pathologies in general, and cataract in particular, upon presenting far visual acuity was examined. The longitudinal data are consistent with cross-sectional data from previously published reports. Older persons who were free from specific visual pathologies exhibited an age-related decline in presenting far acuity as did those with documented visual pathologies. Despite the demonstrated loss in acuity with age, the majority of persons maintain at least fair acuity (20/40 or better) into their 80's.

Adult↗

PubMed1982

Age and iconic read-out.

Letter recognition was investigated in 16 young adults (mean age = 21) and in 16 older men (mean age =64) by exposing seven-letter strings for brief periods followed by a mask. Young adults were able to identify three letters at a rate of 27 msec per letter, a value which is typical of other reports. Any additional letters were identified at a much slower rate. In contrast, older adults were able to identify only two letters, at a rate of 35 msec per letter. Older men thus showed a decline in both the amount of and rate at which information was encoded from the icon within a fixation period. These findings have implications for experiments involving visual arrays.

Adolescent↗