Emergency Medicine

As part of its epidemiologic studies of congenital malformations, the Centers for Disease Control (CDC) conducts two birth defects surveillance systems in the United States. The Metropolitan Atlanta Congenital Defects Programme (MACDP) is an intensive surveillance system using several methods to identify infants born with birth defects in the Atlanta area. The Birth Defects Monitoring Programme (BDMP) is a nationwide surveillance system that monitors 1 million births per year, about a third of all births in the U.S. It relies on diagnoses from newborn discharge summaries to ascertain affected infants. The systems were originally designed to detect potential 'epidemics' of birth defects that could occur following the widespread dissemination of new teratogens similar to thalidomide. In addition to monitoring, they have also proved to be useful resources for a variety of studies of the epidemiology of birth defects.

The descriptive epidemiology of conjoined twinning in the United States was investigated using data from the Birth Defects Monitoring Program (BDMP), a nationwide congenital malformations surveillance system that monitors discharge diagnoses associated with a third of the births in the United States. This is the largest recorded series concerning conjoined twins; data were analyzed on 7,903,000 births monitored by the BDMP in the period 1970–1977. The analysis identified 81 sets of conjoined twins, for a crude incidence of 10.25 per million births. The most common types of conjoined twins were thoracoomphalopagus (28%), thoracopagus (18%), omphalopagus (10%), parasitic twins (10%), and craniopagus (6%). Conjoined twins are more common among females than males, and in nonwhites than whites. No maternal age effect was found. There was no evidence of seasonal or temporal clustering of the cases. The large number of conjoined twins who had birth defects that are not obviously linked to the conjoining (particularly neural tube defects and orofacial clefts) may provide insights into the pathogenesis of birth defects resulting from disordered embryonic migration and fusion.

To evaluate the effectiveness of screening mammography by estimating the variability in radiologists' ability to detect breast cancer within the US population of radiologists at mammography centers accredited by the American College of Radiology. A two-way sample survey design was used as follows. Fifty mammography centers having an American College of Radiology-accredited unit were randomly sampled from across the United States. One hundred eight radiologists from these centers gave blinded interpretation to the same set of 79 randomly selected screening mammograms. The mammograms were from women who had been screened at a large screening center. Before their sampling, these women had been stratified by their breast disease status, established either by biopsy or by 2-year follow-up. Rates of biopsy recommendations were summarized by the mean, median, minimum, maximum, and range of sensitivity and specificity. Overall cancer detection ability was summarized by similar statistics for receiver operating characteristic curve areas. Ninety-five percent lower confidence bounds on the ranges in accuracy measures were established by boo-strapping. There is a range of at least 40% among US radiologists in their screening sensitivity. There is a range of at least 45% in the rates at which women without breast cancer are recommended for biopsy. As indicated by receiver operating characteristic curve areas, the ability of radiologists to detect cancer mammograms varies by as much as 11%. Our findings indicate that there is wide variability in the accuracy of mammogram interpretation in the population of US radiologists. Current accreditation programs that certify the technical quality of radiographic equipment and images but not the accuracy of the interpretation given to mammograms may not be sufficient to help mammography fully realize its potential to reduce breast cancer mortality.

The histories of oral contraceptive (OC) use provided by women participating in a study of hepatocellular adenoma (HCA) were compared with records obtained from their physicians. In the HCA study two memory aids were used to assist women in their recall: a calendar of significant events during a woman's lifetime to which she might relate her use of OCs and a book of colour photographs of the 90 OC preparations available up to the time of the study. Using the number of months of a woman's history which could be checked against physician records (mean for all women of 33 months) as the denominator, the highest proportion of concordance was for month-specific duration of OC use (90%) with lower agreement for duration and brand (62%) and duration, brand, and dose (54%). Agreement was better for cases than for controls.

To investigate whether a family history of breast cancer increases a woman's risk of developing breast cancer, we analyzed data from the Centers for Disease Control's Cancer and Steroid Hormone Study. The 4,735 cases were women 20 to 54 years old with a first diagnosis of breast cancer ascertained from eight population-based cancer registries; the 4,688 controls were women selected at random from the general population of these eight areas. Compared with women without a family history of breast cancer, women who had an affected first-degree relative had a relative risk of 2.3; women with an affected second-degree relative had a relative risk of 1.5; and women with both an affected mother and sister had a relative risk of 14. The risk of breast cancer for a woman was higher if her first-degree relative had unilateral rather than bilateral breast cancer or had breast cancer detected at a younger rather than older age. For women aged 20 to 39, 40 to 44, and 45 to 54 years, the estimated annual incidence of breast cancer per 100,000 women attributable to a first-degree family history of breast cancer was 51.9, 115.1, and 138.6, respectively, and that attributable to a second-degree family history of breast cancer was 12.1, 19.2, and 92.4, respectively.

To determine if body mass Index (BMI = weight [kg]/height [m]2), predictive of mortality in longitudinal epidemiologic studies, was also predictive of mortality in a sample of seriously ill hospitalized subjects. Prospective, multicenter study. Five tertiary care medical centers in the United States. Patients > or = 18 yrs of age who had one of nine illnesses of sufficient severity to anticipate a 6-month mortality rate of 50% were enrolled at five participating sites in the Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatments (SUPPORT). None. Patients were asked their current height and weight as part of the demographic data. Stratifying body mass index by percentile rank (< or = 15, 15 to 85, and > or = 85th percentiles), risk ratios for mortality were calculated by Cox Proportional Hazards using the 15th to 85th percentile of body mass index as the reference group while controlling for multiple variables such as prior weight loss, albumin, and Acute Physiology Score. A body mass index in the < or = 15th percentile was associated with an excess risk of mortality (risk ratio = 1.23; p < .001) within 6 months. High body mass index (> or = 85th percentile) was not significantly related to risk of mortality. Body mass index, a simple anthropometric measure of nutrition employed in community epidemiologic studies, has now been demonstrated to be a predictor of mortality in an acutely ill population of adults at five different tertiary centers. Even when controlling for multiple disease states and physiologic variables and removing from the analysis all patients with significant prior weight loss, a body mass index below the 15th percentile remained a significant and independent predictor of mortality. Examination of patient vs. proxy data did not change the results. Future studies examining variables predictive of mortality should include body mass index, even in acutely ill populations with a poor probability of survival.

We sought to determine the incidence rate of carpal tunnel syndrome in the general population. Using three different case definitions, we conducted a prospective study to ascertain by medical record review all cases of incident disease in a defined population during a 2-year period. Newly diagnosed probable or definite carpal tunnel syndrome (N = 309) occurred at a rate of 3.46 cases per 1,000 person-years (95% confidence interval = 3.07-3.84). The incidence rate in our study was 3.5 times higher than the rate 20 years ago in a Minnesota city. The rate difference probably results from a combination of reasons, including a true rise in incidence.

We studied the association between estrogen replacement therapy (ERT) and the risk of breast cancer as part of the Cancer and Steroid Hormone Study. All subjects in the analysis were postmenopausal women enrolled from eight geographic areas. Women 25 to 54 years old with newly diagnosed breast cancer were identified through population-based tumor registries and diagnosed between Dec 1, 1980, and Dec 31, 1982. Controls were selected from the same eight geographic areas by the random digit dialing of residential telephone numbers. Analyses included 1369 cases and 1645 controls. Among women with bilateral oophorectomy, the relative risk of breast cancer for women who had ever used ERT was 1.3, compared with women who had never used ERT. Among women who had undergone hysterectomy but who still had at least one ovary, the relative risk was 1.1; among women who reported a natural menopause, the relative risk was 0.8. Overall, the risk of breast cancer did not appear to increase appreciably with increasing ERT duration or latency, even for durations and latencies of 20 years or longer.

It has been proposed that hyperthermia in the pregnant woman is associated with neural tube defects in her offspring. We analyzed retrospective interview data for a maternal history of probable febrile illness during the first trimester of pregnancy among mothers of infants with anencephaly or spina bifida. There were two control groups—mothers of infants with Down syndrome and mothers of infants with cleft lip or palate. With the Down syndrome group serving as controls, the incidence of febrile illness among mothers of all infants with neural tube defects was significantly elevated. With the cleft group as controls, the fever incidence was not significantly increased in the neural tube defect groups. When the combined cleft and Down syndrome controls were used, only mothers of the spina bifida group had an elevated fever incidence. Epidemiologic data suggest an association of maternal fever during pregnancy with neural tube defects in the offspring.

To identify risk factors associated with neurologically isolated ischemic ocular motor nerve palsies. Case-control study. Multispecialty clinic providing primary, secondary, and tertiary care in central and northern Wisconsin. After applying strict, predetermined, inclusion and exclusion criteria to the medical records of patients with ocular motor nerve palsies, 65 case patients 50 years of age or older were identified with ischemic ophthalmoplegia. A control subject, matched for sex and exact year of age, was randomly selected for each case patient from individuals undergoing a comprehensive medical evaluation. Prevalence of potential risk factors in case patients and controls, including diabetes, hypertension, hypercholesterolemia, coronary artery disease, left ventricular hypertrophy, adiposity, tobacco use, prior ocular motor nerve palsy, and hematocrit. Risk factors were assessed using standardized definitions. After adjustment for potential confounding factors, significant risk factors and their associated odds ratios (ORs) and 95% confidence intervals (CIs) were as follows: previously diagnosed diabetes, OR = 5.75 (CI = 1.68 to 19.7); left ventricular hypertrophy, OR = 5.20 (CI = 1.30 to 20.82); and, hematocrit (per percentage increase), OR = 1.35 (CI = 1.13 to 1.61). In addition to the generally accepted risk factor of diabetes, left ventricular hypertrophy and elevated hematocrit appeared to be important determinants of ischemic ocular motor nerve palsy. Additional studies should be undertaken to confirm these findings.

To demonstrate the range of gains and losses that radiologists might experience from independent double reading in screening mammography.From a national random sample of radiologists, the authors formed 131 pairs. For each radiologist, the authors analyzed the increase relative to his or her individual true-positive rate (TPR) or false-positive rate (FPR), number of additional cancers detected, and change to negative biopsy rate that would result from independent double reading after pairing.The average radiologist can expect an 8%–14% gain in TPR and a 4%–10% increase in FPR with pairing. For some radiologists, double reading increased the TPR with a small concomitant increase in FPR. Other radiologists, however, realized small gains in TPR with large increases in FPR. Adding the reading from a more experienced radiologist did not necessarily improve the TPR of a radiologist with less experience.Radiologists can from complementary and noncomplementary pairs for double reading. Use of this procedure must be decided on an individual basis.

The protective effect of barrier-method contraception against pelvic inflammatory disease (PID) was examined by analyzing data from the Women's Health Study, a large multicenter case-control study. We compared the contraceptive methods used by 645 women hospitalized for initial episodes of PID with the contraceptive methods used by 2,509 control subjects reporting no history of PID. The risk of hospitalization for PID in women currently using barrier methods relative to women using all other methods and to women using no method of contraception was 0.6 (95% confidence limits, 0.5 to 0.9) for both comparisons. This protective effect was observed for both chemical and mechanical barrier methods, although it was not statistically significant for the former. The prevention of PID and its sequelae is one of the most important noncontraceptive benefits of barrier methods of contraception.

To determine occurrence and sources of farm-work-related injury, we conducted a population-based, prospective study in a large clinic and hospital serving a defined rural area. The population at risk was identified through a unique demographic and medical records linkage system and a special agricultural census. Cases were 510 individuals who sought inpatient or outpatient care from May 1990 through April 1992 from a physician or chiropractor for harm resulting from acute exposure to energy. One per 31 farm residents was treated annually for a farm-work-related injury. Eight percent of these cases were hospitalized. Animals were the most frequent source of injury. Severity did not differ between cases associated with animals, machinery, falls, or chemicals. Thirty-eight percent of farm-work-related injury cases occurred in nonfarm residents. Injury risk was 2.5 times greater among dairy farm residents than among nondairy farm residents, 352.0 vs. 141.0 cases per 10,000 person-years, respectively. Adult male farm residents had 556.9 injuries per 10,000 person-years and 21.3 injuries per million hours of farm work.