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Biomedical subjects

W M O'Fallon

Publications and source records attributed to W M O'Fallon.

At least 127 records · Page 7Linked to original sources
PubMed1996

Incidence and prevalence of intracranial vascular malformations in Olmsted County, Minnesota, 1965 to 1992.

We used the Mayo Clinic medical records linkage system to detect all cases of intracranial vascular malformation (IVM) among residents of Olmsted County, Minnesota from 1965 to 1992 and found 48 IVMs over the 27-year period, including four patients with IVM detected at autopsy, without prior symptoms. Twenty-nine of 48 patients were symptomatic at presentation. From 1985 to 1992, the age- and sex-adjusted detection rate for IVMs excluding asymptomatic autopsy cases was 2.75 in 100,000 person-years (P-Y) (95% CI, 1.6 to 3.9). From 1965 to 1992, the detection rate was 1.84 in 100,000 P-Y (95% CI, 1.3 to 2.4). On January 1, 1990, the age- and sex-adjusted prevalence rate of identified IVMs was 19.0 in 100,000 P-Y (95% CI, 10.5 to 27.5). Detection rates increased from 1965 to 1992, probably due to increased identification of cases because of advances in imaging technology. This study provides unique data on incidence rates of detection and prevalence of IVMs on a population basis.

Adolescent↗
PubMed1996

A population-based model of risk factors for ischemic stroke: Rochester, Minnesota.

The medical record linkage system for the Rochester Epidemiology Project provided the means to identify 1,444 incidence cases of ischemic stroke and age- and sex-matched controls from the population from 1960 to 1984 to conduct a case-control study nested in the population. A multiple logistic-regression model permitted the estimation of odds ratios of ischemic stroke for each risk factor while adjusting for confounding variables. The final model, in addition to age and date of stroke, included transient ischemic attacks, hypertension, current smoking, atrial fibrillation, ischemic heart disease, mitral valve disease (other than prolapse), and diabetes mellitus. The process identified interactions showing that ischemic stroke incidence for persons with transient ischemic attacks was higher in women than in men and that the risk decreased with increasing age; that the risk of stroke with hypertension and also with current cigarette smoking decreased with increasing age; and that the risk of ischemic stroke with intermittent or persistent atrial fibrillation was similar when hypertension was present, but without hypertension the risk of stroke was more than seven times greater with persistent than with intermittent atrial fibrillation. None of the odds ratios differed over the five quinquennia of the study, and no effect of antihypertensive treatment on stroke incidence could be demonstrated in the population.

Aged↗
PubMed1996

Frequency of intracranial hemorrhage as a presenting symptom and subtype analysis: a population-based study of intracranial vascular malformations in Olmsted Country, Minnesota.

The purpose of this study was to determine the symptoms at presentation and the incidence of intracranial hemorrhage (ICrH) caused by intracranial vascular malformations (IVMs) in a defined population. The authors used the Mayo Clinic medical records linkage system to detect all cases of IVM among residents of Olmsted County, Minnesota, during the period 1965 through 1992. Forty-eight IVMs were detected over the 27-year period. Twenty-nine of the 48 patients were symptomatic at presentation. The most common presenting symptom was ICrH, which was present in 20 patients, 69% of all symptomatic cases. Sixty-five percent of arteriovenous malformations (AVMs) presented with ICrH. The most common subtype of ICrH was intracerebral hemorrhage, which was found in nine of 20 patients; the second most common subtype was subarachnoid hemorrhage. The peak occurrence of hemorrhage was during the fifth decade of life. The age- and gender-adjusted occurrence of a first ICrH from an IVM among residents of Olmsted County, Minnesota was 0.82 per 100,000 person years (95% confidence interval 0.46-1.19). There was no increase in the detection of IVM-related ICrH throughout the study period. The 30-day mortality rate following ICrH was 17.6% for patients with an AVM and 25% for all patients with IVMs. This study provides unique data on symptoms at presentation and the incidence of ICrH and hemorrhage subtypes from IVMs on a population basis.

Adolescent↗
PubMed1996

Stroke incidence, prevalence, and survival: secular trends in Rochester, Minnesota, through 1989.

BACKGROUND AND PURPOSE: Trends in stroke incidence and mortality are available from few sites worldwide. The unique nature of the medical care in patients from Rochester, Minn, has allowed the ascertainment of virtually all cases of stroke for community residents for the period dating from 1955. This study updates incidence rates, stroke mortality, radiological imaging availability, and prevalence for stroke and subtypes of stroke though 1989 and evaluates trends since 1955. METHODS: Medical records of all residents of Rochester with potential diagnosis of stroke during the 5-year period through December 31, 1989 were screened to determine whether the case met the criteria for stroke. The type of stroke was determined with the use of all available data. Average annual age- and sex-adjusted incidence rates for stroke and various types of stroke were calculated for 5-year periods from 1955 to 1989. Prevalence of stroke was also determined. Poisson regression was used to better clarify the dependence of stroke incidence on multiple variables. Cox proportional hazards modeling evaluated trends in short-term and long-term stroke survival. RESULTS: We found that 496 incidence cases of stroke occurred among Rochester residents during 1985 to 1989. The annual age- and sex-adjusted stroke incidence rates was 145 per 100 000 population, which was virtually unchanged from 1980 to 1984 and 13% higher than the rate determined in 1975 to 1979. Increasing incidence rates compared with the 1970s were noted in all groups aged older than 54 years and in both sexes. Survival after cerebral infarction was dependent on age and calendar year when trends dating from 1955 were evaluated. The annual incidence rate of intraparenchymal hemorrhage was twice that of subarachnoid hemorrhage. CONCLUSIONS: Incidence rates for stroke have remained at a high rate than those determined in the 1970s. Although the occurrence of untreated hypertension has been reported to be stable or decreasing, the incidence rate of stroke is higher than those noted during the decline in stroke incidence during the 1960s and 1970s. In addition to the impact of radiological imaging, increased contribution of patients with ischemic heart disease, and the possible detection of milder cases of stroke, other factors, which are undefined, may be contributing to the increased stroke incidence rates detected over the last 10 years.

Adult↗
PubMed1996

Utilization of acute care services in the year before and after first stroke: A population-based study.

There is a need for accurate population-based data on the utilization of medical resources after stroke. The present study used the Rochester Stroke Registry to identify all Rochester, Minnesota residents with confirmed first stroke (hospitalized and nonhospitalized) during the period of 1987 to 1989 (n=292). Events were categorized by type of stroke and assigned Rankin severity. Inpatient and outpatient acute care activity for the 12 months before and after stroke for each individual were obtained from billing tapes provided by Mayo Clinic, Olmstead Medical Group, and affiliated hospitals. These providers account for >95% of acute care received by Rochester residents. The results showed that despite high poststroke mortality, total charges in the year after stroke were 3.4 times those for the previous year. Although greater than 50% of utilization in the year poststroke occurred within the first 30 days, mean monthly charges for acute care remained significantly above prestroke levels for up to 5 months after the event. Poststroke charges per person-day of follow-up were significantly higher for individuals who were hospitalized for the event, who had subarachnoid hemorrhage, whose stroke occurred after admission to the hospital for another reason, and who died within 7 days. Significantly lower poststroke charges were evident for persons with mild cerebral infarctions and persons whose stroke occurred in a nursing home. Neither prestroke utilization, age category, nor sex were predictive of poststroke charges. The unique population-based data presented here have important implications for efforts toward stroke prevention, intervention, and cost containment.

Aged↗
PubMed1996

Mental retardation in a birth cohort, 1976-1980, Rochester, Minnesota.

The cumulative incidence of mental retardation in a birth cohort of children born from 1976 through 1980 in Rochester, Minnesota (n = 5,919) was estimated. Rochester is the site of the Rochester Epidemiology Project, which captures virtually all medical care delivered locally. Passive follow-up through school and community medical records for criteria diagnostic of mild or severe mental retardation was undertaken. Thirty children were classified with mental retardation. The cumulative incidence of mental retardation by age 8 years was 9.1 per 1,000 (95% confidence interval = 6.2, 13.0) and was similar for boys and girls (8.3 vs. 10.0 per 1,000, respectively). The cumulative incidence for severe mental retardation in girls was more than twice that in boys; for mild retardation it was the opposite. The cumulative incidence among boys was 1.7 times greater than the cumulative incidence for girls. Results suggest that although the overall incidence of mental retardation by gender was similar, the severity may differ somewhat.

Child↗
PubMed1996

A diagnostic algorithm for distinguishing the eosinophilia-myalgia syndrome from fibromyalgia and chronic myofascial pain.

OBJECTIVE: To develop a diagnostic algorithm for the eosinophilia-myalgia syndrome (EMS) that complements the existing case definition. METHODS: We conducted a retrospective study using data on 59 clinical and laboratory variables from a consecutive referral cohort of 91 patients with EMS meeting the Centers for Disease Control and Prevention case definition. Age and sex matched controls included 93 patients with fibromyalgia and 99 patients with chronic myofascial pain. The study period was March 1989 to April 1992. Recursive partitioning was used to create a diagnostic algorithm. RESULTS: In the 283 case patients and controls with disabling myalgias, 4 differentiating variables identified patients with EMS: extremity edema, leukocyte count > 12.5 x 10(9)/l, dyspnea, and absence of arthralgias. These 4 variables form a diagnostic algorithm that has a sensitivity of 95.6%, a specificity of 96.9%, and positive and negative predictive values of 93.5 and 97.9%, respectively. CONCLUSION: This algorithm is practical and can be easily applied in any medical setting. It also readily distinguishes EMS from other common myalgia syndromes.

Adult↗
PubMed1996

Evaluation of glucocorticosteroid injection for the treatment of trochanteric bursitis.

OBJECTIVE: We conducted an open observational study to assess the short and longterm effect of single local glucocorticosteroid injection for trochanteric bursitis. METHODS: 75 patient diagnosed with trochanteric bursitis based on clinical criteria were injected; 20, 32, and 22 patients each received 6, 12, and 24 mg betamethasone, respectively, mixed with 4 cm3 of 1% lidocaine. A standardized baseline questionnaire was administered to assess the severity and functional limitation due to trochanteric pain, including the visual analog scale for pain. Patients were followed at Weeks 1, 6, and 26 to determine their response to treatment. RESULTS: 77.1, 68.8, 61.3% of responding patients reported improvement in pain at Week 1, 6, and 26, respectively. Patients receiving higher doses of betamethasone were more likely to experience pain relief (p < 0.0123). CONCLUSION: Corticosteroid and lidocaine injection for trochanteric bursitis is an effective therapy with prolonged benefit.

Aged↗
PubMed1995

The incidence of giant cell arteritis in Olmsted County, Minnesota: apparent fluctuations in a cyclic pattern.

OBJECTIVE: To investigate trends in the incidence of giant cell arteritis over a 42-year period in Olmsted County, Minnesota. DESIGN: Population-based incidence study. SETTING: Olmsted County, Minnesota. METHODS: All incidence cases of giant cell arteritis first diagnosed between 1950 and 1991 were identified using the unified record system at Mayo Clinic. Age- and sex-specific incidence rates were calculated using the number of incidence cases as the numerator and population estimates as the denominator. Overall rates were age- and sex-adjusted to the 1980 United States white population. The annual incidence rates were graphically illustrated using a 3-year centered moving average. RESULTS: Between 1950 and 1991, 125 Olmsted County residents (103 women and 22 men) were diagnosed with giant cell arteritis. The age- and sex-adjusted incidence per 100,000 persons 50 years of age or older was 17.8 (95% CI, 14.7 to 21.0); incidence was significantly higher in women (24.2 [CI, 19.5 to 28.9]) than in men (8.2 [CI, 4.8 to 11.6]). Age-specific incidence rates increased with age (P < 0.0001). The annual incidence rates increased significantly over the study period (P = 0.002) and appear to have clustered in five peak periods, which occurred about every 7 years. A significant calendar-time effect was identified; it predicted an increase in incidence of 2.6% (CI, 0.9% to 4.3%) every 5 years. CONCLUSIONS: Our observation of a regular cyclic pattern in incidence rates over time supports the hypothesis of an infectious cause for giant cell arteritis. Similar studies in other populations are needed to confirm our findings.

Age Distribution↗
PubMed1995

Increased incidence of aortic aneurysm and dissection in giant cell (temporal) arteritis. A population-based study.

OBJECTIVE: To determine the frequency of aneurysm and dissection of the aorta in patients with giant cell arteritis and to assess the effects of these events on these patients. DESIGN: Population-based cohort study. SETTING: A multispecialty and a primary care clinic in southern Minnesota. PATIENTS: 96 residents of Olmsted County, Minnesota, who developed giant cell arteritis between 1950 and 1985. The presence of aortic aneurysm, dissection, or both was confirmed using computed tomography, ultrasonography, angiography, or autopsy. RESULTS: 11 of the 96 patients were found to have thoracic aortic aneurysms. In 2 of these patients, the aneurysms were detected when giant cell arteritis was diagnosed. In the remaining 9 patients, the aneurysms occurred a median of 5.8 years after giant cell arteritis was diagnosed. Six of the 11 died suddenly of acute thoracic aortic dissection. Five patients who did not have thoracic aortic aneurysms developed isolated abdominal aortic aneurysms a median of 2.5 years after giant cell arteritis was diagnosed. The incidence of thoracic aortic aneurysm in patients with giant cell arteritis was 999 per 100,000 person-years; the incidence of abdominal aortic aneurysm in these patients was 555 per 100,000 person-years. Compared with all persons of the same age and sex living in Olmsted County, patients with giant cell arteritis were 17.3 times (95% Cl, 7.9 to 33.0) more likely to develop thoracic aortic aneurysm and 2.4 times (Cl, 0.8 to 5.5) more likely to develop isolated abdominal aortic aneurysm. CONCLUSIONS: Giant cell arteritis is associated with a markedly increased risk for the development of aortic aneurysm, which is often a late complication and may cause death.

Aged↗
PubMed1995

Population-based study of the contribution of weather to hip fracture seasonality.

Previous studies have demonstrated seasonal increases in hip fracture incidence, but none have directly assessed the influence of inclement weather on this seasonality. In this study, the daily occurrence of hip fracture among women aged 45 years and older in Rochester, Minnesota, from 1952 through 1989 was ascertained using the resources of the Rochester Epidemiology Project and compared with the occurrence of inclement weather as recorded in hourly readings by the National Weather Service in Rochester for the same time period. Among the women aged 45-74 years, the risk of hip fracture was increased on days with snow (relative risk (RR) = 1.41, 95% confidence interval (CI) 1.10-1.81) or freezing rain (RR = 1.82, 95% CI 1.27-2.62). In this group, the elevated risk of hip fracture in winter, compared with summer (RR = 1.44, 95% CI 1.0-2.09), was reduced after controlling for weather (RR = 1.16, 95% CI 0.81-1.65). Among women aged 75 years and older, ice and snow were not strongly related to fracture occurrence. The winter-related increase in risk (RR = 1.16, 95% CI 0.96-1.40) was essentially unchanged after controlling for weather and was similar to the weather-adjusted seasonality of hip fracture occurrence in younger women. These data suggest that there are factors other than weather that may be linked to the seasonal pattern in hip fracture occurrence and that operate at all ages.

Aged↗
PubMed1995

The trends in incidence of primary brain tumors in the population of Rochester, Minnesota.

A number of reports have suggested an increasing incidence of primary brain tumors, especially malignant astrocytomas, in the elderly population. To investigate this issue, we analyzed the incidence and temporal trends of primary intracranial neoplasms diagnosed in the population of Rochester, Minnesota, over the 40 years between 1950 and 1990. The incidence of symptomatic primary brain tumors (excluding patients diagnosed incidentally at autopsy and by neuroimaging studies) increased from 9.5 per 100,000 population per year in 1950 to 1969 to 12.5 per 100,000 per year in 1970 to 1989; this change was not statistically significant (chi 2 trend, 1.89; p = 0.17). While the incidence of pituitary adenomas increased significantly between the two periods (chi 2 trend, 4.44; p = 0.04), the incidence trends of all gliomas, malignant astrocytomas, and meningiomas showed no change among persons younger than 65 years as well as those 65 years and older. The number of patients incidentally found to have neoplasms by neuroimaging studies increased in the recent 20-year period (chi 2 trend, 4.08; p = 0.04). The average age- and sex-adjusted incidence rates per 100,000 per year during the study period in the population of Rochester, Minnesota, for symptomatic tumors were 5.0 for all gliomas, 3.3 for malignant astrocytomas, 2.0 for meningiomas, and 2.4 for pituitary adenomas. In conclusion, our data indicate that the reported increase in the incidence of primary brain tumors is an artifact of improvement in diagnostic technology and practice.

Adenoma↗
PubMed1995

Epidemiology of polymyalgia rheumatica in Olmsted County, Minnesota, 1970-1991.

OBJECTIVE: To determine the incidence, prevalence, and survival of polymyalgia rheumatica (PMR) over a 22-year period in Olmsted County, Minnesota. METHODS: Using the unified record system at the Mayo Clinic for the Olmsted County population, we reviewed all medical records with a diagnosis of PMR from 1970 through 1991. RESULTS: There were 245 (173 female; 72 male) incidence cases of PMR between 1970 and 1991. The average annual age- and sex-adjusted incidence of PMR per 100,000 population > or = 50 years was 52.5 (95% confidence interval [CI] 45.9-59.2), with a significantly higher incidence in females (61.7; 95% CI 52.3-71.2) than in males (39.9; 95% CI 30.7-49.2). The incidence varied over the period of observation, but no significant trends were found. The prevalence of PMR among persons > or = 50 years on January 1, 1992 was 6/1,000. There was a small but significantly increased survival rate among male PMR patients compared with the general population. CONCLUSION: Our data demonstrate that PMR is a common nonfatal disease in the elderly, the incidence and clinical manifestations of which have varied but remained relatively stable over the last 2 decades.

Age Distribution↗
PubMed1995

The contribution of vitamin D receptor gene alleles to the determination of bone mineral density in normal and osteoporotic women.

Bone mass and its mineral content are under genetic control. The vitamin D receptor (VDR) gene has been shown to be a major locus for genetic effects on bone mineral density (BMD), and polymorphisms in this gene accounted for a large proportion of genetic variance in BMD in an Australian population. In this study, we investigated whether similar associations are present in a North American population. We studied 139 normal healthy women (age 53.2 +/- 14.5, mean +/- SD) and 43 severely osteoporotic postmenopausal women (age 65.8 +/- 5.9). In the 127 of them with complete genetic studies, the distribution of genotypes, determined by polymerase chain reaction on leukocyte DNA samples, agreed closely with that in the Australian population. BMD was strongly related to age and weight, and, thus was adjusted for these parameters prior to genetic analysis. We found that age modulated the effect of VDR genotypes on femoral neck BMD (FN-BMD) (TaqI, p = 0.036; BsmI, p = 0.118; ApaI, p = 0.041) such that the effect of genotype was greatest among younger (premenopausal) women and declined with age so that there was no discernible difference by age 70. Among the younger women, a high FN-BMD was associated with the TT (or aa or bb) genotype while low FN-BMD was associated with the tt (or AA or BB) genotype.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Predictors of hip fractures in elderly men.

To assess the influence on the risk of hip fractures in men of medical conditions associated with secondary osteoporosis or with an increased likelihood of falling, we conducted a population-based nested case-control study among the 232 Rochester, Minnesota, men with an initial hip fracture due to moderate trauma in 1965-1989 and an equal number of age-matched control men from the general population. Information on selected medical and surgical conditions and certain behavioral risk factors prior to fracture (or comparable index date for controls) was obtained from inpatient and outpatient medical records in the community that averaged over 36 years in duration. After adjusting for age, obesity, and inactivity, disorders linked with secondary osteoporosis were associated with a 2-fold increase in the risk of hip fracture in men (odds ratio [OR] 2.3; 95% confidence interval [CI] 1.3-4.3), while conditions linked with an increased risk of falling were associated with almost a 7-fold increase in risk (OR 6.9; 95% CI 3.3-14.8). These factors together appeared to account for about 72% of the hip fractures in men. Increased attention must be paid to these conditions which, in aggregate, are very common in elderly men and lead to a substantial increase in the risk of hip fracture with its devastating sequelae of death, disability and cost.

Adult↗
PubMed1995

Age-related hip fractures in men: clinical spectrum and short-term outcomes.

Clinical spectrum, treatment and short-term outcomes were assessed among the 131 Rochester, Minnesota, men who contracted an initial hip fracture due to moderate trauma during 1978-89. Three-fourths of falls leading to hip fracture occurred indoors with little seasonality, and 91% of fractures were in men 65 years of age or older. The ratio of cervical to intertrochanteric femur fractures was 1.4:1, and there was a tendency toward more neurological conditions among the patients with cervical fractures. Hemiarthroplasty and total hip replacement were mostly performed for cervical fractures, while internal fixation was preferred for intertrochanteric fractures. In-hospital mortality was 11.5%, and the 30-day case fatality rate was 16.0%. Age and postoperative deterioration of mental status significantly increased the risk of early death, the latter even after adjustment in a multivariate model, while comorbidity had a suggestive but not statistically significant influence on mortality. More than half the men were discharged to nursing homes, and 79% of the patients who survived at 1 year resided in nursing homes or intermediate care facilities or were attended by home care. Only 41% of survivors recovered their prefracture level of functioning and nearly 60% of patients limped and required a cane or walker. After implementation of the prospective payment system in 1984, the length of hospital stay was reduced, but there was no change in early mortality rates, in the duration of physical therapy following fracture or in attendance at nursing homes. The results of this population-based study demonstrate the strong impact of hip fractures on short-term outcomes in men.

Accidental Falls↗
PubMed1995

Trends in the utilization of silicone breast implants, 1964-1991, and methodology for a population-based study of outcomes.

Using the unique data resources of the Rochester Epidemiology Project, we have designed a population-based retrospective cohort study to examine the risks and complications of silicone breast implants among 749 Olmsted County, Minnesota, women who received these devices between 1964 and 1991, and 1498 control women who did not receive such devices. In this paper, we present data describing the population-based trends in the utilization of these devices from 1964 to 1991. In addition, we discuss the case ascertainment, outcome assessment, and reliability of the data collection for the outcomes study. The utilization of breast implants increased markedly over the past 30 yr with the rate of new implants per 100,000 women (> or = 15 years of age) rising from 3.5 in 1964 to 95 in 1979, remaining stable thereafter. The prevalence of breast implants among Olmsted County women > or = 15 years of age on 1 January 1992 was approx. 1%. An examination of the characteristics of these women reveals that recent utilization of breast implants has increased more rapidly among rural than among urban women, that the proportion of women receiving implants for breast cancer mastectomy reconstruction has increased in recent years, and that the great majority of women receiving implants are married at the time of implant. These trends also revealed that the average age of women who receive implants is rising and that in more recent years both much younger and much older women are receiving implants.

Adolescent↗