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Biomedical subjects

C M Beard

Publications and source records attributed to C M Beard.

At least 37 records · Page 2Linked to original sources
PubMed1994

Comparison of respondents and nonrespondents in an osteoporosis study.

We attempted to enroll an age-stratified random sample of Rochester, Minnesota women > or = 30 years of age in a population-based prospective study of the determinants of bone loss. Using the resources of the Rochester Epidemiology Project, 541 women were contacted and 305 agreed to participate. Of 236 nonrespondents, 38 were ineligible and 198 refused to participate resulting in a 61% response rate for eligible subjects. We reviewed community medical records for respondents and nonrespondents (including ineligibles) to determine whether the two groups differed with regard to variables that might be important in osteoporosis research. There was little difference between respondents and nonrespondents for a history of cigarette smoking, hyperthyroidism, thyroidectomy, or age-related fractures. Respondents survived better, were less likely to be obese or have renal failure, and more likely to have had an oophorectomy and consume alcohol (P < 0.01). These data suggest that nonrespondents were less healthy than respondents.

Adult↗
PubMed1994

Incidence of leukemia in Olmsted County, Minnesota, 1975 through 1989.

OBJECTIVE: To determine the incidence of leukemia in Olmsted County, Minnesota, for a recent 15-year period and to compare the data with reported rates for the previous 40 years. DESIGN: We conducted a population study of leukemia diagnosed between 1975 and 1989 in residents of Olmsted County by review of medical records identified through diagnostic indexes, death certificates, autopsy files, and histologic preparations. MATERIAL AND METHODS: Diagnoses of leukemia were categorized into various subtypes, and age- and sex-specific incidence rates were calculated for leukemia as a whole and for each subtype. In addition, incidence rates were age- and sex-adjusted to the 1970 US white population for comparison with earlier published rates. Age and annual trends as well as sex differences were assessed with the generalized linear interactive model approach. RESULTS: During 1975 through 1989, the mean annual incidence rate for leukemia was 12.3 per 100,000 population in Olmsted County. When adjusted for age and sex, the rate per 100,000 was 13.6, in comparison with a similarly adjusted rate of 11.8 for the previous decade (1965 through 1974). The rates for chronic myelogenous leukemia and acute lymphocytic leukemia remained stable throughout the entire study period; however, rates for acute myelogenous leukemia and chronic lymphocytic leukemia increased, most prominently in patients 50 years of age or older. This increased rate occurred in both males and females, but the incidence rates for both subtypes began increasing earlier for males than for females. CONCLUSION: Although we cannot rule out an actual increase in incidence rates for these types of leukemia in the elderly population, we believe that the increase in persons older than 50 years of age reflects social change in improved health care and its better utilization by elderly persons, as well as the ability to diagnose leukemia earlier than in the past.

Adolescent↗
PubMed1994

Incidence of chronic lymphocytic leukemia in Olmsted County, Minnesota, 1935 through 1989, with emphasis on changes in initial stage at diagnosis.

OBJECTIVE: To determine whether the stage at the time of diagnosis of chronic lymphocytic leukemia (CLL) had changed during a 55-year period. DESIGN: We conducted a study of the cohort of residents of Olmsted County, Minnesota, who had been diagnosed as having CLL during the period from 1935 through 1989. MATERIAL AND METHODS: By analysis of medical records, patients with CLL were characterized by Rai stage, absolute lymphocyte count, age at diagnosis, need for therapy, and reported cause of death in nonsurvivors. Trends for these variables were analyzed by decade throughout the study period. RESULTS: The overall annual incidence rate of CLL per 100,000 population in Olmsted County increased from 2.6 in the 1935 through 1944 period to 5.4 in the 1975 through 1984 period; however, the increasing rate was found only for those 50 years of age or older and was especially dramatic for those 75 years old or older. Analysis of Rai stage over time demonstrated an increase in the proportion of cases diagnosed as Rai stage 0. In addition, the median absolute lymphocyte count decreased, the median time to initiation of therapy increased, and the median age of patients with Rai stage 0 CLL at the time of diagnosis increased over time. Overall, 54% of patients had received therapy for CLL by the time of last follow-up. Among the nonsurvivors, CLL was documented as the underlying or a contributing cause of death in 69%. CONCLUSION: The overall increase in CLL was thought to be due to enhanced methods of early diagnosis and improved health care for the elderly population. Thus, artifact may best explain the observed trend, although we cannot exclude the possibility of an actual increase in incidence rates over time.

Adult↗
PubMed1994

Alzheimer's disease and cumulative exposure to anesthesia: a case-control study.

OBJECTIVE: To evaluate prior exposure to general anesthesia as a potential risk factor for Alzheimer's disease (AD). DESIGN: A retrospective, population-based, case-control study. SETTING: The Rochester Epidemiology Resource. PATIENTS: Cases were all incident cases of AD from 1975 to 1984 who resided for 40 years or more in Olmsted County prior to the onset of their dementia (n = 252). One age- and gender-matched control for each case was selected from all registrations for care at Mayo Clinic during the year of onset in the incident case. The case and control groups each had 252 individuals. Of these, 208 cases and 199 controls had at least one exposure to general anesthesia prior to the year of onset of dementia in the matched AD patient. MEASUREMENTS: The cumulative duration of anesthesia and the total number of general anesthetic exposures prior to the age of onset of dementia and the corresponding year in each matched control were ascertained. RESULTS: There was no significant difference in mean cumulative exposure (in minutes) to general anesthesia (patients vs controls: 188.4 vs 170.5 minutes, ns). Neither exposure to six or more episodes of general anesthesia (OR = 1.44; 95% CI: 0.77-2.71) nor cumulative exposure to 600 minutes or more of general anesthesia (OR = 1.63; 95% CI: 0.53-5.04) were associated with a significantly increased risk of AD. CONCLUSION: It is unlikely that multiple exposures to general anesthesia increase the risk of AD.

Aged↗
PubMed1994

Fracture risk in patients with Alzheimer's disease.

OBJECTIVE: To assess the risk of fracture following onset of Alzheimer's disease. DESIGN: Retrospective (historical) cohort study. SETTING: Population-based in Rochester, Minnesota. PARTICIPANTS: All 543 Rochester residents with onset of Alzheimer's disease during the 10-year period, 1975-84, and an equal number of age- and sex-matched controls from the community. MEASUREMENTS: Fractures were assessed through review of each subject's complete (inpatient and outpatient) medical records in the community. MAIN RESULTS: Rochester residents with Alzheimer's disease were no more likely to have a history of fracture prior to onset than were matched controls from the same population. During the year of onset, there was a 2-fold excess of fractures at various sites among those with Alzheimer's disease. The risk ratio for any fracture subsequently was 1.1 (95% CI 0.9, 1.3), and this slight increase was accounted for entirely by a 2.7-fold increase in the risk of hip fracture (95% CI 1.8, 4.2). CONCLUSIONS: Fracture risk was not increased before the onset of Alzheimer's disease, although there was an excess of fractures around the time that Alzheimer's disease came to clinical attention. Fracture risk was not elevated thereafter except for a substantial increase in the risk of hip fracture. This suggests a link with certain falls rather than generalized disuse osteoporosis.

Adult↗
PubMed1994

Incidence of multiple myeloma in Olmsted County, Minnesota: 1978 through 1990, with a review of the trend since 1945.

PURPOSE: Incidence rates of multiple myeloma appear to have increased in recent decades, but it is difficult to compare the incidence rates over time because of changes in laboratory procedures, differences in diagnostic criteria, and variations in indexing of medical records. However, Olmsted County, Minnesota, provides a rare opportunity to minimize these limitations, because the medical care has been provided mainly by the Mayo Clinic. PATIENTS AND METHODS: Records of Olmsted County residents with a diagnosis of multiple myeloma from January 1, 1978 through December 31, 1990 were reviewed. Criteria for diagnosis and residency were the same as in previous Olmsted County studies. RESULTS: The incidence rate per 100,000 age-adjusted to the 1950 United States white population was 5.4 for males and 2.8 for females; the overall rate was 4.1. The rates were age-adjusted to the 1950 United States population for comparison with earlier data from this population. The rates increased with age for both sexes. There was no significant change in incidence rates from 1945 through 1990. A comparison of the median age for Olmsted County patients with the age of those referred to the Mayo Clinic from elsewhere indicated that the local patients were appreciably older (74 v. 62 years, respectively). Thirty-two of 55 patients (58%) with multiple myeloma from 1978 through 1990 had a monoclonal plasma-cell proliferative process before the diagnosis of multiple myeloma. CONCLUSION: The incidence rate of multiple myeloma in Olmsted County, Minnesota, has not changed significantly during the past 46 years. We believe that reports of increasing rates over time are mainly due to improved case ascertainment.

Adolescent↗
PubMed1994

Are patients with Alzheimer's disease surviving longer in recent years?

We report the survival experience of the incidence cohort of Alzheimer's disease (AD) patients in Rochester, Minnesota, whose onset occurred during the years 1960 to 1984. Survival was evaluated relative to year of onset, age at onset, and gender. Survival was better among women than men and improved for those with AD with more recent onset. The relative hazard decreased by a factor of 0.82 for each decade. The effect of age at onset was nonlinear, indicating that the hazard of death does not change at a constant rate with age.

Age of Onset↗
PubMed1994

Incidence of cluster headaches: a population-based study in Olmsted County, Minnesota.

The epidemiology of cluster headache is virtually unknown. Using the unique resources of the Rochester Epidemiology Project for population-based studies, we identified 26 Olmsted County, Minnesota, residents who fulfilled the International Headache Society criteria for newly diagnosed cluster headache between 1979 and 1981. As part of a large study of migraine and cluster headache, we screened more than 6,400 patient records from several diagnostic rubrics to obtain this cohort, accomplished case ascertainment exclusively through medical record review, and assigned diagnoses by the consensus of two neurologists. The age-adjusted incidence was 15.6 per 100,000 person-years (p-y) (95% CI, 8.9 to 22.3) for males and 4.0 per 100,000 p-y for females (95% CI, 0.4 to 7.6). The overall age- and sex-adjusted incidence was 9.8 per 100,000 p-y (95% CI, 6.0 to 13.6) or approximately 1/25 that of migraine. The peak incidence was among men aged 40 to 49 years and women 60 to 69 years. There was a higher than expected prevalence of history of smoking among males with cluster headaches (p < 0.05), supporting the possibility that smoking predisposes to the development of cluster headaches in men.

Adolescent↗
PubMed1994

Prior blood transfusions and Alzheimer's disease.

We performed a population-based, case-control study to evaluate prior blood transfusion as a potential risk factor for Alzheimer's disease (AD). All cases were incident cases of AD from 1975 to 1984 with residence for 40 years or more in Olmsted County, Minnesota, prior to their onset of dementia (N = 252). There was one age- and gender-matched control for each case. We ascertained the number of blood transfusions prior to the age of onset of dementia and the corresponding year in each control. Sixty-five cases and 55 controls had at least one prior blood transfusion. We did not find a significantly increased risk of AD for the events of at least one, three, or six blood transfusions.

Adult↗
PubMed1993

Is the incidence of dementing illness changing? A 25-year time trend study in Rochester, Minnesota (1960-1984)

We performed a time trend study of incidence of dementing illness in Rochester, Minnesota. We ascertained age- and sex-specific incidence rates for the five quinquennia, 1960 through 1984. The incidence rates sharply increased with advancing age, reaching a high of 2,922/100,000 person years in the group 85 years and older. For dementia caused either solely or predominantly by Alzheimer's disease, this figure was 2,600/100,000 person years for the oldest age group. There were no significant differences in the incidence of dementing illness between men and women. In the oldest age groups in the last two quinquennia of study, there appears to be a trend toward increasing incidence rates. Over the years, the proportion of cases attributed to dementia due to unknown causes has decreased while the proportion of cases attributed to Alzheimer's disease has increased.

Adult↗
PubMed1992

Incidence and natural history of primary systemic amyloidosis in Olmsted County, Minnesota, 1950 through 1989.

No reports of the incidence rates for primary systemic amyloidosis (AL) have come to our attention. Records of all residents of Olmstead County, Minnesota, with a diagnosis of amyloidosis were obtained from the Mayo Clinic and its affiliated hospitals, as well as other medical groups that might have seen local patients for the period January 1, 1950 to December 31, 1989. Twenty-one patients fulfilled the criteria for the diagnosis of AL. The median age was 73.5 years, and 62% were men. In all but one patient the diagnosis was made ante mortem. The clinical data of the 21 patients were similar to those referral patients with AL seen at Mayo Clinic. Immunohistochemical stains were positive for monoclonal light chains in the amyloid deposits in 15 of the 21 cases. In six cases, tissue was not available for immunohistochemical studies. Three of the six patients without immunohistochemical stains had a free monoclonal lambda light chain in the urine, and the other three had a monoclonal serum protein. Immunoelectrophoresis/immunofixation detected a monoclonal (M)-protein in the serum of 16 of 17 patients tested. A monoclonal light chain was found in the urine of 10 of 15 patients. The overall sex- and age-adjusted rate per million person-years was 6.1 from 1950 to 1969 and 10.5 from 1970 to 1989. The similarity of these rates suggests no significant increase over time.

Aged↗
PubMed1992

Interobserver variability in medical record review: an epidemiological study of asthma.

Interobserver variability during the data collection for a large retrospective study of asthma was assessed. After extensive training by three physician investigators, two nurses collected study data from existing medical records using an explicit protocol. At four time intervals, samples of records already abstracted by one nurse were reviewed and re-abstracted by another nurse assigned to the project. The unweighted kappa coefficient was used to evaluate observer reliability. Most of the kappa coefficients were > or = 0.6, suggesting good to excellent agreement. Agreement was highest for demographic, clinical and medication variables, while judgement variables had the lowest kappa coefficients. The well known dependence of kappa on the prevalence of the variable studied was evident in these data. We strongly recommend periodic monitoring of observer reliability in any study using more than one individual to collect data to ensure reliable data collection.

Asthma↗
PubMed1992

Conditions associated with carpal tunnel syndrome.

With use of a comprehensive medical records-linkage system, we identified the comorbid conditions and risk factors in the residents of Rochester, Minnesota, who had a diagnosis of carpal tunnel syndrome during 1961 through 1980. In 43.2% of the 1,016 patients, no associated conditions were found on review of the medical records, whereas associated conditions were documented in 56.8%. The most frequent of these conditions were Colles' fracture, rheumatoid arthritis, hormonal agents or oophorectomy (or both), diabetes mellitus, and, among men, occupations that involved excessive use of the hands. Rheumatoid arthritis, diabetes mellitus, and pregnancy were significantly more frequent among the study patients with carpal tunnel syndrome than in the general population of Rochester, Minnesota. The standardized morbidity ratio was 3.6 for rheumatoid arthritis, 2.3 for diabetes mellitus, and 2.5 for pregnancy. The population attributable risk for pregnancy among women 15 to 44 years old was 7.0%. The standardized morbidity ratio for polymyalgia rheumatica was not significantly increased.

Adolescent↗
PubMed1992

Body mass index and the initial manifestation of coronary heart disease in women aged 40-59 years.

A population-based case-control study was conducted to evaluate body mass as a coronary heart disease (CHD) risk factor among women 40-59 years of age. Cases were women aged 40-59 whose first manifestation of CHD was angina (No. = 133), nonfatal myocardial infarction (No. = 90), and sudden unexpected death (No. = 18) during 1960-1982. Two randomly selected controls were matched on age and time of the initial disease manifestation of the case. The adjusted relative risk for weight and body mass index respectively demonstrated a moderate association with all CHD as well as with angina, but no association with definite CHD (myocardial infarction or sudden unexpected death). To determine if the observed association between body mass index and angina was possibly attributable to differential misclassification bias (i.e. obese women were, in contrast to non-obese women, preferentially labelled as having coronary artery disease) data for angina were stratified by confirmed versus unconfirmed cardiac origin. In the unconfirmed angina analysis, the 75th percentile for weight contrasted with the 25th percentile was associated with a 50% increase in the risk of being labelled as having angina (adjusted odds ratio (OR) = 1.59, 95% confidence interval (CI): 1.11-2.28), while a similar contrast for Quetelet Index was also associated with a nearly 2-fold increase in the risk of being labelled as having angina (adjusted OR = 1.74, 95% CI: 1.18-2.57).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Lack of association between Alzheimer's disease and education, occupation, marital status, or living arrangement.

Using the resources of the Rochester Epidemiology Project, we conducted a case-control study of sociodemographic characteristics using the incidence cohort of patients with Alzheimer's disease (AD). During the conduct of ongoing studies of AD in Rochester, we identified new cases of AD as they occurred during 1975-1979 (N = 241). We selected one age- and sex-matched control from among all registrations for care in this community during the year of onset for each case. There was little difference between cases and controls for educational attainment, marital status, type of dwelling, living arrangement, or occupation. We were unable to confirm low educational level as a risk factor for AD in this population. Future attempts to identify etiologic risk factors for dementing illness should probably move toward other areas of research.

Aged↗
PubMed1992

Incidence of migraine headache: a population-based study in Olmsted County, Minnesota.

To determine the incidence of clinically detected migraine headache in the defined population of Olmsted County, MN, 1979-1981, we screened over 6,400 patient records from several diagnostic rubrics using the unique resources of the Rochester Epidemiology Project for population-based studies. We identified 629 Olmsted County residents who fulfilled the International Headache Society's 1988 criteria for newly diagnosed migraine headache between 1979 and 1981. The overall age-adjusted incidence was 137 per 100,000 person-years for males and 294 per 100,000 person-years for females. The highest incidence in females was among those aged 20 to 24 years (689 per 100,000 person-years), and in males, the highest incidence was among those aged 10 to 14 years (246 per 100,000 person-years). From 1979 to 1981, there was a striking increase in the age-adjusted incidence in those under 45 years of age: the incidence increased 34% in women and 100% for men. This is the first population-based study of migraine incidence across all ages.

Adolescent↗
PubMed1991

Tuberous sclerosis complex in Olmsted County, Minnesota, 1950-1989.

The incidence of tuberous sclerosis complex in Olmsted County, Minnesota, was 0.28 per 100,000 person-years from 1950 through 1989, the point prevalence on December 31, 1989, was 6.9 per 100,000 persons, and the incidence at birth was 6.0 per 100,000 live births. The incidence was 0.13 per 100,000 person-years from 1950 through 1974 and 0.46 per 100,000 person-years from 1975 through 1989. The higher rate of diagnosis during the later period is believed to be due to the use of computed tomography. Of the 12 patients considered in this study, one patient presented with seizures and severe intellectual disability, six patients presented with seizures, three patients presented with multiple facial angiofibroma, and two patients were asymptomatic.

Female↗