Biomedical subjects

W M O'Fallon

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

At least 91 records · Page 5Linked to original sources

PubMed1999

Comorbidity in arthritis.

OBJECTIVE: To describe the relative frequency of selected comorbidities in 2 population based prevalence cohorts of patients with rheumatoid arthritis (RA) and osteoarthritis (OA) compared to age and sex matched community controls. METHODS: Using the population based data resources of the Rochester Epidemiology Project, we assembled 3 prevalence cohorts of all residents of Olmsted County, Minnesota, with RA (1987 American College of Rheumatology criteria) and age and sex matched controls without arthritis on January 1, 1965, January 1, 1975, and January 1, 1985. Cases and controls were followed longitudinally through their complete (inpatient and outpatient) medical records beginning 10 years prior to the prevalence (or index) date until death, migration from the county, or January 1, 1995. Comorbidity was assessed yearly using the Charlson Comorbidity Index and the Index of Co-existent Diseases (ICED). Descriptive statistics were used to illustrate the baseline characteristics of the study population and the frequency of individual comorbidities in each of the 3 groups over the followup period. Cox proportional hazards modeling was used to assess the risk for each individual comorbidity among patients with arthritis compared to controls and to identify significant predictors of an increase in comorbidity level over time. RESULTS: Our study population included 450 RA, 441 OA, and 891 control subjects. The age and sex distributions of cases and their controls were similar. Over the followup period, patients with RA had a higher likelihood of developing congestive heart failure, chronic pulmonary disease, dementia, and peptic ulcer disease, while cases with OA had a significantly higher risk of developing peptic ulcer disease and renal disease. Among patients with either RA or OA, age, male sex, and baseline comorbidity were significant predictors of a rise in comorbidity. The presence of RA was a highly significant predictor of a rise in comorbidity from one year to the next, even after controlling for the effects of age, sex, and baseline comorbidity (p = 0.0004 for the Charlson and p = 0.006 for the ICED). CONCLUSION: These data indicate that the burden of illness among people with arthritis is higher than for nonarthritics and that this burden appears to be increasing over time, particularly in RA. These results suggest that specialized chronic disease care will be increasingly important for the future health care needs of people with RA.

Arthritis, Rheumatoid↗

PubMed1999

Mortality in rheumatoid arthritis: have we made an impact in 4 decades?

OBJECTIVE: To evaluate trends in survival among patients with rheumatoid arthritis (RA) over the past 4 decades. METHODS: Three population based prevalence cohorts of all Rochester, Minnesota, residents age > or =35 years with RA (1987 American College of Rheumatology criteria) on January 1, 1965, January 1, 1975, and January 1, 1985; and an incidence cohort of all new cases of RA occurring in the same population between January 1, 1955 and January 1, 1985, were followed longitudinally through their entire medical records (including all inpatient and outpatient care by any provider) until death or migration from the county. Mortality was described using the Kaplan-Meier method and the influence of age, sex, rheumatoid factor (RF) positivity, and comorbidity (using the Charlson Comorbidity Index) on mortality was analyzed using Cox proportional hazards models. RESULTS: Mortality was statistically significantly worse than expected for each of the cohorts (overall p<0.0001). A trend toward increased mortality in the 1975 and 1985 prevalence cohorts compared to the 1965 prevalence cohort was present, even after adjusting for significant predictors of mortality (age, RF positivity, and comorbidity). Survival for the general population of Rochester residents of similar age and sex improved in 1975 compared to 1965, and in 1985 compared to 1975. CONCLUSION: The excess mortality associated with RA has not changed in 4 decades. Moreover, people with RA have not enjoyed the same improvements in survival experienced by their non-RA peers. More attention should be paid to mortality as an outcome measure in RA.

Adult↗

PubMed1998

Trends in the incidence of deep vein thrombosis and pulmonary embolism: a 25-year population-based study.

BACKGROUND: The incidence of venous thromboembolism has not been well described, and there are no studies of long-term trends in the incidence of venous thromboembolism. OBJECTIVES: To estimate the incidence of deep vein thrombosis and pulmonary embolism and to describe trends in incidence. METHODS: We performed a retrospective review of the complete medical records from a population-based inception cohort of 2218 patients who resided within Olmsted County, Minnesota, and had an incident deep vein thrombosis or pulmonary embolism during the 25-year period from 1966 through 1990. RESULTS: The overall average age- and sex-adjusted annual incidence of venous thromboembolism was 117 per 100000 (deep vein thrombosis, 48 per 100000; pulmonary embolism, 69 per 100000), with higher age-adjusted rates among males than females (130 vs 110 per 100000, respectively). The incidence of venous thromboembolism rose markedly with increasing age for both sexes, with pulmonary embolism accounting for most of the increase. The incidence of pulmonary embolism was approximately 45% lower during the last 15 years of the study for both sexes and all age strata, while the incidence of deep vein thrombosis remained constant for males across all age strata, decreased for females younger than 55 years, and increased for women older than 60 years. CONCLUSIONS: Venous thromboembolism is a major national health problem, especially among the elderly. While the incidence of pulmonary embolism has decreased over time, the incidence of deep vein thrombosis remains unchanged for men and is increasing for older women. These findings emphasize the need for more accurate identification of patients at risk for venous thromboembolism, as well as a safe and effective prophylaxis.

Adolescent↗

PubMed1998

Influence of fracture criteria on the outcome of a randomized trial of therapy.

Based on a presumption that the morphometric approach to vertebral fracture assessment is beset by false positive deformities, it has been suggested that more stringent criteria should be used to asses vertebral fracture outcomes in clinical trials of osteoporosis therapies. We applied a variety of criteria in the reanalysis of a randomized trial of sodium fluoride therapy for women with established osteoporosis. Although progressively more severe criteria reduced the cumulative incidence of a new vertebral fracture in both those receiving a placebo and the fluoride-treated patients, differences between the two groups were not magnified and none of the suggested approaches produced a statistically significant result. These findings indicate that the false positive rate associated with morphometric assessment of vertebral fractures is not so great as supposed from theoretical considerations that assume independence among the measurements. Our findings also provide some reassurance that differences in the criteria used to define a vertebral fracture are not the controlling influence in the likelihood that a particular clinical trial will find a result favoring one treatment over another.

Aged↗

PubMed1998

Long-term trends in the incidence of distal forearm fractures.

In this population-based descriptive study covering the 50-year period, 1945-94, there was a statistically significant increase in distal forearm fractures due to severe trauma in both women and men (p < 0.001) but no secular increase in fractures due to moderate trauma (approximately osteoporosis). Since fractures attributed to severe trauma comprised a greater proportion of the total in men (52%) than women (21%), an overall doubling of age-adjusted forearm fracture incidence in men between 1945 and 1994 was statistically significant (p < 0.001), but the 7% increase in age-adjusted rates among women was not (p = 0.90). While the epidemiological pattern of distal forearm fracture incidence in Rochester was similar to that seen elsewhere, the overall incidence rate of 287.4 per 100,000 person-years (95% CI 267.7-307.1) in 1985-94 was less than current rates in Sweden, presumably because the great increase in distal forearm fracture incidence seen, for example, in Malmö between 1953-57 and 1980-81 was not observed in Rochester. The trends in distal forearm fracture rates in Rochester men and women over the past 50 years are broadly consistent with trends in hip fracture incidence in this community over the same time span.

Adult↗

PubMed1998

Survival after the diagnosis of hyperparathyroidism: a population-based study.

BACKGROUND: Reports of increased mortality from cardiovascular disease and malignancy in primary hyperparathyroidism have been based primarily on patients who have undergone parathyroidectomy. In order to assess the true impact of primary hyperthyroidism on mortality in the general population, we assessed survival in a large inception cohort of Rochester, Minnesota residents with primary hyperparathyroidism initially diagnosed over a 28-year span, the majority of whom were followed with uncomplicated disease. METHODS: All Rochester residents with primary hyperparathyroidism first recognized in 1965 to 1992 were identified through the Rochester Epidemiology Project medical records linkage system. Included as cases were patients with pathologic confirmation of hyperthyroidism, hypercalcemia with inappropriately elevated parathyroid hormone levels, or hypercalcemia for more than a year with no other cause. Survival was estimated using the Kaplan Meier product-limit method. The Cox proportional hazards model was used to determine associations, as relative hazards (RR) with 95% confidence intervals (CI), of various risk factors with time to death. RESULTS: During the study period, 435 cases of primary hyperparathyroidism were identified. Altogether, parathyroid surgery was performed on 126 patients (29%), with a mean delay between the initial elevated serum calcium level and surgery of 3.3 years. Patients who underwent surgery had higher maximum serum calcium levels than the patients who were observed (mean+/-SD, 11.3+/-0.7 versus 10.7+/-0.4 mg/dL, P <0.00 1), but their mean ages were similar (54+/-16 versus 56+/-17 years). Overall survival in the patients with primary hyperthyroidism was better than expected (P=0.02), but by age-adjusted multivariate analysis, higher maximal serum calcium level was an independent predictor of mortality (RR=1.3 per mg/dL; 95% CI: 1.1-1.6; P <0.02). CONCLUSION: Overall survival is not adversely affected among unselected patients with mild primary HPT in the community, although patients with more severe disease, as manifested by higher serum calcium levels, may have an increased risk of death.

Calcium↗

PubMed1998

Fracture risk among patients with urolithiasis: a population-based cohort study.

In a population-based retrospective cohort study, 624 Rochester, Minnesota residents with an initial symptomatic episode of urolithiasis in 1950 to 1974 were followed for 11,909 person-years for subsequent age-related fractures. During this period of observation, the number of patients with a first vertebral fracture was over four times the number expected on the basis of vertebral fracture incidence rates in the general population of Rochester [standardized morbidity ratio (SMR), 4.3; 95% confidence interval, 3.4 to 5.3]. The risk of vertebral fracture was elevated among men as well as women, and was associated with increasing age and with the use of corticosteroids for more than six months. However, vertebral fracture risk was increased nearly fourfold (SMR 3.9; 95% confidence interval, 3.0 to 4.9) among the urolithiasis patients without such exposure, which suggests that corticosteroids do not completely account for the association with vertebral fractures. There was no increase in the risk of hip, pelvis, proximal humerus or distal forearm fractures in this cohort of patients, and their survival was not impaired. Additional studies are needed to define the pathophysiology of vertebral fractures among patients with urolithiasis.

Adolescent↗

PubMed1998

Risk factors for ischemic stroke in a Russian community: a population-based case-control study.

BACKGROUND AND PURPOSE: This study was conducted to determine the risk factors for ischemic stroke in a defined Russian population. METHODS: Our data are based on a population-based case-control study of 237 patients with first-ever ischemic stroke and 237 age- and sex-matched controls. Logistic regression methods for matched pairs were used to estimate the relative risk for the variables studied. RESULTS: In a multivariate analysis, hypertension, left ventricular hypertrophy on electrocardiography, ischemic heart disease, mitral valve disease, current cigarette smoking, and high body mass index were significant and independent risk factors for ischemic stroke in this Russian community. CONCLUSIONS: The significant risk factors for ischemic stroke in Novosibirsk are similar to those from other populations and cohorts. This study, the first of stroke risk factors in Russia, has implications for clinical practice and the planning of stroke prevention in the population.

Aged↗

PubMed1998

Incidence of transient ischemic attack in Rochester, Minnesota, 1985-1989.

BACKGROUND AND PURPOSE: There is scant information available on the incidence of transient ischemic attack (TIA) in a defined population. This study defines incidence rates of first TIA and subtypes of TIA during 1985-1989 and compares the incidence to that obtained from a 1960-1972 cohort study. METHODS: Medical records of all residents of Rochester with potential diagnosis of TIA during 1985-1989 were screened to determine whether the case met the criteria for TIA. All available data were used to determine the vascular distribution of the TIA. Average annual age- and sex-adjusted incidence rates were calculated for 1985-1989, and results were compared with incidence rates determined in a Rochester-based 1960-1972 cohort study. RESILTS: Two hundred two cases of first TIA or amaurosis fugax occurred among Rochester residents during 1985-1989. The age- and sex-adjusted incidence rate for any TIA was 68/100 000 population. Incidence of amaurosis fugax was 13/100 000; anterior circulation (cerebral) TIA, 38/100 000; and vertebrobasilar distribution TIA, 14/100 000. Rates were similar to those determined from a 1960-1972 cohort study. CONCLUSIONS: The incidence rate of TIA is 41% that of stroke incidence. TIA incidence in Rochester, Minn, is higher than has been previously reported for other sites throughout the world. Although comparison with prior time periods is difficult because of ascertainment issues, it appears that there has been no significant change in TIA incidence since the decade of the 1960s or earlier. This suggests that the most common mechanism for TIA (atherosclerosis) has not changed in prevalence, nor have risk factors leading to this mechanism.

Adolescent↗

PubMed1998

A defect in renal calcium conservation may contribute to the pathogenesis of postmenopausal osteoporosis.

Although all postmenopausal women are estrogen deficient, women who have postmenopausal osteoporosis may have a defect, in addition to estrogen deficiency, that accounts for their higher rates of bone resorption and greater bone loss, relative to those who do not. To test the hypothesis that one defect is an impairment in renal calcium conservation, we measured renal calcium transport in 19 osteoporotic and 19 normal postmenopausal women, whose ages (median and 25th-75th percentile range) were 70 yr (range, 67-72) and 72 yr (range, 69-74), respectively. There was no difference between groups in values for serum ionized calcium and PTH concentrations or in renal filtered load of calcium. However, before PTH infusion, the osteoporotic women had lower (P = 0.0046) values for tubular reabsorption of calcium (TRCa) of 96.8% (range, 96.0-97.1) vs. 98.0% (range, 97.2-98.3) and higher (P = 0.0154) urinary calcium excretion of 0.194 mg/dL of glomerular filtrate (GF) (0.154-0.239) vs. 0.125 mg/dL of GF (0.103-0.173) than the normal women. After infusion of 200 U of synthetic PTH (synthetic 1-34 analog of human PTH), TRCa increased and calcium excretion decreased comparably in both groups, so that the differences between groups after intervention remained: for TRCa, 98.3% (97.7-98.6) vs. 98.9% (98.4-99.3; P = 0.0042); and for calcium excretion, 0.099 mg/dL of GF (0.080-0.138) vs. 0.066 mg/dL of GF, (0.045-0.097, P = 0.0180). In conclusion, postmenopausal women with osteoporosis have a PTH-independent defect in renal calcium conservation. This defect is of sufficient magnitude to contribute to the greater negative calcium balance in post-menopausal women with osteoporosis vs. their postmenopausal peers.

Absorption↗

PubMed1998

Relationship of serum sex steroid levels and bone turnover markers with bone mineral density in men and women: a key role for bioavailable estrogen.

Estrogen (E) deficiency associated with the menopause is the major cause of bone loss in aging women. However, men also lose significant amounts of bone with age, but they do not have the equivalent of menopause, and serum total testosterone (T) and E levels decline only marginally with age in men. Thus, it has been difficult to attribute bone loss in aging men to either T or E deficiency. Here, we show in a population-based, age-stratified sample of 346 men, aged 23-90 yr, that serum total T and E (estradiol plus estrone) levels decreased over the life span by 30% and 12%, respectively, but bioavailable (or nonsex hormone-binding globulin-bound) T and E levels decreased by 64% and 47%, respectively. In these men and in a parallel cohort of 304 women, aged 21-94 yr, serum PTH increased 84% and 64% over the life span, and urinary N-telopeptide of type I collagen (NTx) excretion, a bone resorption marker, increased 77% and 80% between age 50-85 yr in the men and women, respectively. By univariate analyses, serum bioavailable T and E levels correlated positively with bone mineral density (BMD) at the total body, spine, proximal femur, and distal radius and negatively with urinary NTx excretion in men and women. Urinary NTx excretion was also negatively associated with BMD in both sexes. By multivariate analyses, however, serum bioavailable E level was the consistent independent predictor of BMD in both men and postmenopausal women. Thus, bioavailable E levels decline significantly with age and are important predictors of BMD in men as well as women. These studies suggest that in contrast to traditional belief, age-related bone loss may be the result of E deficiency not just in postmenopausal women, but also in men.

Adult↗

PubMed1998

Survival and recurrence after first cerebral infarction: a population-based study in Rochester, Minnesota, 1975 through 1989.

We used the Kaplan-Meier product limit method to estimate rates and Cox proportional hazards regression analysis with bootstrap validation to model significant independent predictors of and temporal trends in survival and recurrent stroke among 1,111 residents of Rochester, MN, who had a first cerebral infarction from 1975 through 1989. The risk of death after first cerebral infarction was 7% +/- 0.7% at 7 days, 14% +/- 1.0% at 30 days, 27% +/- 1.3% at 1 year, and 53% +/- 1.5% at 5 years. Independent risk factors for death after first cerebral infarction were age (p < 0.0001), congestive heart failure (p < 0.0001), persistent atrial fibrillation (p < 0.0001), recurrent stroke (p < 0.0001), and ischemic heart disease (p < 0.0001 for age < or =70, p > 0.05 for age >70). The risk of recurrent stroke after first cerebral infarction was 2% +/- 0.4% at 7 days, 4% +/- 0.6% at 30 days, 12% +/- 1.1% at 1 year, and 29% +/- 1.7% at 5 years. Age (p = 0.0002) and diabetes mellitus (p = 0.0004) were the only significant independent predictors of recurrent stroke. Neither the year nor the quinquennium of the first cerebral infarction was a significant determinant of survival or recurrence. The temporal trend toward improving survival after first cerebral infarction documented in Rochester, MN, in the decades before 1975 has ended.

Aged↗

PubMed1998

Ischemic stroke: outcomes, patient mix, and practice variation for neurologists and generalists in a community.

A variety of methods was used to compare patient mix, practice variation, survival, and recurrence after first ischemic stroke among Rochester, MN residents. The significance of the results for neurologists and generalists was examined. Age, stroke severity, congestive heart failure (CHF), and the interaction between atrial fibrillation and patient groups were determinants of survival. Without atrial fibrillation, patients on neurology services and patients on general services with neurology consultation had better survival than those without neurology consultation, adjusting for age, stroke severity, and CHF. With atrial fibrillation, patients on general services with neurology consultation had no better survival compared with those without neurology consultation; patients on neurology services had worse survival (p=0.002). There was no difference in stroke recurrence. Evaluation by a neurologist is associated with better survival for most patients with ischemic stroke but not those with atrial fibrillation. Only a randomized trial can determine whether this association is causal.

Adult↗

PubMed1998

Stroke-attributable nursing home use: a population-based study.

OBJECTIVE: To estimate 1) among patients with stroke, nursing home use attributable to stroke, and 2) the savings in nursing home use, assuming strokes were prevented. METHODS: All confirmed cases of first stroke among Rochester, Minnesota, residents from 1987 through 1989 (n = 290) and one nonstroke control of same gender and similar age for each patient were followed up in provider-linked medical records and State of Minnesota nursing home files until emigration, death, or December 31, 1994. Data included disability and place of residence at baseline (i.e., date of stroke for each patient and their corresponding control), length of follow-up, cumulative incidence of nursing home admission, proportion of follow-up spent in a nursing home, and number of nursing home days. RESULTS: Before baseline, patients and controls were similar in the level of disability (mean Rankin = 1.7 for patients and 1.6 for controls) and the proportion in a nursing home (11% for both groups). Among those not in the nursing home at baseline, 5-year cumulative incidence of first admission was 48% for cases versus 20% for controls. Survival was significantly shorter for cases than for controls; the proportion of follow-up spent in the nursing home was 20% for cases versus 11% for controls. When controlling for survival, cases experienced an average of 110 (95% CI, 63 to 156) more nursing home days per person than controls in the first five years. When nursing home use during differential survival was included, the difference in nursing home days between cases and controls was no longer significant (p = 0.16). CONCLUSIONS: Stroke prevention would result in fewer cases admitted to the nursing home, older age at first admission, and a smaller proportion of remaining life spent in the nursing home, but stroke prevention would not result in fewer nursing home days.

Aged↗

PubMed1998

Incidence and prevalence of intracranial aneurysms and hemorrhage in Olmsted County, Minnesota, 1965 to 1995.

BACKGROUND: There are no previous reports of the incidence rate of intracranial saccular aneurysms in a defined population. METHODS: Medical records of all residents of Olmsted County, MN, with a possible intracranial saccular aneurysm (IA) were reviewed. Incidence rates and prevalence of symptomatic and asymptomatic IAs, aneurysmal intracranial hemorrhage (ICH), and frequency of IA detection based on size and site were determined. RESULTS: A total of 348 IAs were detected among 270 persons during the 31-year period from 1965 to 1995, including 188 symptomatic patients at presentation (166 with ICH). The age- and sex-adjusted incidence rate for IAs excluding asymptomatic autopsy cases was 9.0/100,000 person-years (P-Y; 95% CI, 7.8 to 10.2). The rate of detection in women (10.7/100,000 P-Y; 95% CI, 8.9 to 12.4) was higher than in men. The highest incidence of IA was among those age 55 to 64 years in men, and 65 to 74 years in women. The incidence rate of aneurysmal ICH was 6.9/100,000 P-Y (95% CI, 5.9 to 8.0). Aneurysms were seven times more likely to be detected in the anterior circulation, and this ratio was not altered significantly by age or gender. On January 1, 1990, the age- and sex-adjusted prevalence rate of identified IAs was 83.4/100,000 population (95% CI, 64.1 to 102.7). CONCLUSIONS: This study provides unique data on the population-based incidence and prevalence rates of IAs.

Adolescent↗

PubMed1998

Bone density and fracture risk in men.

We evaluated different definitions of osteoporosis in a population-based sample of 348 men (age 22-90 years) compared with 351 women (age 21-93 years). Thirty-six men (10%) and 46 women (13%) had a history of osteoporotic fracture (hip, spine, or distal forearm due to moderate trauma at >/= age 35). In logistic regression analysis, osteoporotic fracture risk was associated with bone mineral density (BMD) at all sites (neck, trochanter, total hip, lumbar spine, and total wrist) in both genders (p < 0.001) except spinal BMD in men. After adjusting for age, total hip BMD was the strongest predictor of fracture risk in women (odds ratio [OR] per 1 SD decline, 2.4; 95% confidence interval [CI], 1.6-3.7), while wrist BMD was best in men (OR, 1.5; 95% CI, 1.1-2.0). Among men but not women, bone mineral apparent density (BMAD) was a better predictor of fracture than BMD (wrist BMAD OR, 1.7; 95% CI, 1.3-2.3). Hip BMD/BMAD decreased linearly from age 20 years onward in both genders, while spinal BMD/BMAD declined after age 40 in women but not in men. In both genders, total wrist BMD/BMAD decreased after age 50. By World Health Organization criteria, the age-adjusted prevalence of osteoporosis at the hip, spine, or wrist was 35% among women >/=50 years of age. A similar approach (BMD > 2.5 SD below the young male mean) produced an osteoporosis prevalence rate in men >/=50 years of age of 19%. Thus, bone density predicts fracture risk in men as it does in women, and the prevalence of osteoporosis in men, using sex-specific normal values, is substantial. These observations indicate a need for better prevention and treatment strategies for men.

Adult↗

PubMed1998

Long-term effects of calcium supplementation on serum parathyroid hormone level, bone turnover, and bone loss in elderly women.

We report a 4-year randomized, double-blind, placebo-controlled clinical trial in 236 normal postmenopausal women (mean age +/- SE, 66.3+/-0.2 years) who were randomized to a calcium (1600 mg/day as the citrate) or placebo group. The women were seen every 6 months; 177 completed the trial. Net percentage changes in each group are given relative to baseline. The differences in net percentage changes (calcium group minus placebo group) in medians were: for lumbar spine bone density, 2.0% (p < 0.001) at year 1 and 0.3% (not significant) at year 4; for proximal femur bone density, 1.3% (p = 0.003) at year 1 and 1.3% (p = 0.015) at year 4; and for total body bone mineral, 0.4% (p = 0.002) at year 1 and 0.9% (p = 0.017) at year 4. Similar differences at year 4 were: -18.9% (p = 0.002) for parathyroid hormone (PTH), -11.9% (p = 0.026) for serum osteocalcin, and -32.2% (p = 0.003) for urine free pyridinoline. We conclude that long-term administration of calcium supplements to elderly women partially reverses age-related increases in serum PTH level and bone resorption and decreases bone loss. However, the effects on bone loss were weaker than those reported for estrogen, bisphosphonates, or calcitonin therapy, indicating that calcium supplements alone cannot substitute for these in treating established osteoporosis. Nonetheless, because of their safety, high tolerance, and low expense, calcium supplements may be a useful preventive measure for elderly postmenopausal women whose bone mineral density values are normal for their age.

Aged↗

PubMed1997

The rise and fall of primary hyperparathyroidism: a population-based study in Rochester, Minnesota, 1965-1992.

BACKGROUND: The introduction of routine measurement of serum calcium levels led to a sharp increase in the incidence of primary hyperparathyroidism in the early 1970s. OBJECTIVE: To evaluate the trends in the incidence of primary hyperparathyroidism since the mid-1970s. SETTING: Rochester and Olmsted County, Minnesota. DESIGN: Population-based descriptive study. PATIENTS: All residents of Rochester, Minnesota, who received an initial diagnosis of primary hyperparathyroidism between 1965 and 1992 were identified through the medical records linkage system of the Rochester Epidemiology Project. Included as persons having definite cases (92% of the total) were patients with pathologically confirmed hyperparathyroidism, hypercalcemia with inappropriately elevated parathyroid hormone levels, or hypercalcemia that had lasted for more than a year and had no cause other than primary hyperparathyroidism. MEASUREMENTS: Incidence rates were calculated and directly standardized to the population structure of white persons in the United States in 1990. RESULTS: From 1965 to June 1974 (the prescreening era), the age- and sex-adjusted incidence of primary hyperparathyroidism in Rochester was 15 cases per 100,000 person-years. After measurement of calcium levels was added to the automated serum chemistry panel in July 1974, the incidence increased to 112 per 100,000 person-years in 1975 and then decreased somewhat, reflecting a sweeping effect. Despite improved case ascertainment, however, the incidence rate has continued to decrease; in 1992, the incidence was 4 per 100,000 person-years. A few patients had complications that might have been caused by hyperparathyroidism (22% between 1965 and June 1974 and 6% thereafter), and survival was not impaired in either period. The maximum serum calcium levels did not change (P = 0.15). CONCLUSIONS: The progressive decrease in the incidence of primary hyperparathyroidism is unexpected and suggests a significant change in the epidemiology of this disease.

Adult↗