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C A Huether

Publications and source records attributed to C A Huether.

34 records · Page 2Linked to original sources
PubMed1983

Projection of Down's syndrome births in the United States 1979-2000, and the potential effects of prenatal diagnosis.

This study projects the annual number of Down's syndrome (DS) births during 1979-2000 by maternal age categories, and estimates the effects of prenatal chromosomal diagnosis utilization on reducing these baseline projections. Assuming no reduction in DS births through prenatal diagnosis, projected DS births increase from about 4,300 in 1979 to 5,300 in 1990, where the level would remain approximately stable throughout the 1990s. Applying Ohio's 1980-1981 prenatal chromosomal diagnosis utilization ratio of 17 per cent to women greater than or equal to 35 results in a maximum of 6 per cent reduction in the annual baseline projections of DS births over the next two decades. However, if amniocentesis utilization by women age 30-34 increases to 37.5 per cent and to 75 per cent by women greater than or equal to 35, a one-fourth to one-third annual reduction is achieved throughout the period studied. A substantial increase in prenatal diagnosis appears necessary to offset the projected increase in DS births resulting from a larger number of births to women greater than or equal to 35.

Adolescent↗
PubMed1983

An analysis for paternal-age effect in Ohio's Down syndrome births, 1970-1980.

The purpose of this study was to analyze Down syndrome (DS) births during 1970-1980 in the State of Ohio for a paternal-age effect independent of maternal age. Birth certificates and chromosome analysis records were used to ascertain 1,244 white DS births, which by capture-recapture methodology were estimated to comprise two-thirds of all white DS births in Ohio for this period. The control data consisted of 1,667,210 white live births in Ohio during the same period. One method of statistical analysis was a case-control comparison, which for each single-year maternal age compares the mean paternal age for controls with each observed DS paternal age. No statistically significant paternal-age effect was found in nine of the 11 years. For two of the years, and for all years combined, the DS fathers were significantly younger than the fathers of controls. When the data were subdivided according to ascertainment, one subpopulation--those DS individuals obtained from birth certificates alone--also showed a statistically significant negative paternal-age effect. The Mantel-Haenszel test was also applied to these data. Assuming no paternal-age effect, a lower rate of DS births than expected was found at paternal ages greater than or equal to 40, but not at greater than or equal to 45, greater than or equal to 50, or greater than or equal to 55. These same methods were used to test for a maternal-age effect. In each of the 11 years and over all 11 years combined, a strong and statistically significant positive maternal-age effect was detected.

Adolescent↗
PubMed1982

Influence of demographic factors on annual Down's syndrome births in Ohio, 1970-1979, and the United States, 1920-1979.

Because of the high correlation between advanced maternal age and the risk of Down's syndrome, the demographic factors of population age structure and age-specific birth rates are expected to have considerable effect on Down's syndrome births. The principal objective of this research was to clarify the past and present role of dramatic changes in these two demographic factors within the United States in determining the number and incidence of Down's syndrome births, and the percentage of these births to women greater than or equal to 35. The main hypothesis is that demographic events, modified by increasing use of amniocentesis, adequately account for the general trends regarding Down's syndrome births reported in the recent literature, as opposed to other explanations such as environmental factors or a real biologic increase in Down's syndrome births in younger women. The hypothesis was tested using estimates of the annual number of Down's syndrome births in Ohio for 1970-1979, obtained through use of the Lincoln-Peterson Capture-Recapture method of estimating population size. These were compared to predicted N derived from Ohio demographic data and single year maternal age Down's syndrome risk rates from Upstate New York. The two values of N were in statistical agreement in 8 of the 10 years compared, and show an overall incidence of Down's syndrome in Ohio during the 1970s of 1.20. Using USA government demographic data and Ohio 1970-1979 single year maternal age Down's syndrome risk rates, predicted Down's syndrome births were derived for the USA during 1920-1979. The results show a long-term decline over the period in predicted number (6870 to 4232), incidence (2.42 to 1.23), and percentage of Down's syndrome births to women greater than or equal to 35 (64.3 to 23.4). A precipitous decline in all three values was obtained for the 1960s and early 1970s, with an abrupt end to the declines during the mid 1970s. Predicted number of Down's syndrome births rose 10.4% during the last half of the decade from a low of 3835 in 1975, and is expected to continue to rise rapidly throughout the 1980s, principally as a result of the large increase in the number of women moving into the older age categories.

Amniocentesis↗
PubMed1982

An analysis for temporal variation in Down syndrome births in Ohio, 1970-1979.

Our study investigates the epidemiology of Down syndrome (DS) in the state of Ohio during the 1970s. The occurrence of DS births was examined to learn if statistically significant temporal variation was present among these data. Both monthly and annual numbers of DS births, adjusted for changing numbers of live births, were tested for such variation; furthermore, the data were analyzed for cyclic variation by attempting to fit simple trigonometric functions to the data. Individuals with DS were ascertained using the records of cytogenetics laboratories and birth certificate records. Demographic data such as race, date of birth, and maternal age were collected on these individuals using their birth certificates as the data source. Appropriate parallel live-birth data were obtained from the Ohio Department of Health. The total number of affected individuals ascertained was 1,364, 66.7% of the total estimated population size. The data analysis was restricted to whites only (1,203 individuals) because they represented a more homogeneous sample than the total.Monthly and annual variation in the numbers of live births was removed by producing single-year maternal-age adjusted numbers of DS births using the total Ohio white live births as the reference population. Analysis of covariance using single-year maternal ages </= 16 and >/= 45 as the covariate was used to analyze the adjusted numbers of DS births for temporal variation. No significant differences were detected among the annual adjusted numbers of DS births (P = .24), nor were there differences among the monthly adjusted numbers of DS (P = .37). The modes of ascertainment were tested to learn if there were annual or monthly differences in the method of ascertainment. No significant differences were detected for these data (P = .82 and P = .85, respectively). Furthermore, the data were separated into the maternal-age categories < 35 and >/= 35, and annual and monthly adjusted DS births to these two maternal-age categories were examined for temporal variation. No significant differences were found among these data, P > .10 for all four of the tests. No simple cyclic functions were found to fit either the annual or monthly data. The Ohio study reported here showed that through the use of a large sample, controlling for variation in the numbers of live births, and the use of detailed statistical tests, no significant temporal variation in the occurrence of DS births existed during the 1970s.

Adult↗
PubMed1981

Down's syndrome: percentage reporting on birth certificates and single year maternal age risk rates for Ohio 1970-79: comparison with upstate New York data.

Estimates of single year maternal age risk rates for Down's Syndrome births to White residents of Ohio over the period 1970-79 are reported. The rates were estimated from birth certificate data, which first necessitated estimating the percentage of reporting of Down's Syndrome on Ohio birth certificates. Using data from cytogenetic laboratories within the state, percentages of Down's Syndrome cases reported were found to be 36.5 (319/875) for White and 33.9 (342/1,010) overall. Final single year maternal age risk rates reported here are corrected for underreporting using these figures. They should be useful for genetic counselors and obstetricians. Comparisons of observed, uncorrected single year maternal incidence rates were made within Ohio 1970-74 vs 1975-79, and between Ohio and upstate New York for various time periods using both a hierarchial log-linear model for multiway cross-tabulations and a weighted least squares solution. All comparisons showed excellent agreement, indicating no evidence for temporal or geographic differences and implying that environmental factors are unimportant in determining single year maternal age incidence rates in Down's Syndrome for the time periods and populations studied.

Adolescent↗
PubMed1981

Human genetics teaching in U.S. medical schools.

Information about instruction in genetics was obtained fron 103 of the 107 U.S. four-year medical schools. Seventy-two percent of the schools provide a compulsory course in genetics, but there was great variation in duration, content, departmental responsibility for giving the course, and in the disciplines of those doing the teaching. The variability in the number of hours devoted to teaching genetics was reflected in the competence of the students in giving correct answers to questions on genetics posed by the National Board of Medical Examiners. Electives and continuing education courses on genetics are given by two-thirds and one-half of the schools, respectively; but the subject receives very little attention in departments of preventive, community, or family medicine or in schools of allied health sciences. These findings suggest that genetics has not yet found a natural and comfortable context in the curricula of U.S. medical schools.

Education, Medical↗
PubMed1980

Reduction of bias in estimating the frequency of recessive genes.

The standard approach to estimating the frequency of a completely recessive autosomal gene is to use the maximum-likelihood estimator (MLE), q = square root q2. Since the expectation oof Q using MLE is systematically less than the true value, this estimator always gives a negatively biased estimate of q. Here we describe the bias associated the MLE over a range of q and N values, explore some of the properties of this estimator, and propose new estimators which reduce the bias. We also describe some of the new estimators' properties, as well as the remaining bias associated with them for varying q and N values. We further propose one of these estimators as the one which most effectively reduces bias over a specific q value range of approximately .005 to .05, and which is less biased than JLE over essentially all q and N values. The proposed estimator also is directly compared with MLE in calculating various available estimates of q, demonstrating the percentage of reduction in bias achieved. This reduction varies from negligible for estimates of q above .3 and N greater than 100, to a 23% reduction in bias for a q value of .09 and an N value of 215.

Gene Frequency↗
PubMed1978

Familial spastic paraplegia-clinical and pathologic studies in a large kindred.

Clinical studies of members of a six-generation kindred of familial spastic paraplegia support the diagnostic distinction of a pure form of this autosomal dominant disease. Onset was in the fourth decade or later and symptoms were those of progressive gait difficulties with lower limb spasticity and weakness. Sensor, cerebellar and cranial nerve changes were absent. Pathologic changes in one member were confined to the lateral corticospinal tracts and in the fasciculus gracilis.

Adult↗
PubMed1975

A clinical study of vasectomy failure and recanalization.

An analysis was made of the 26 unsuccessful operations from the 2,197 vasectomies performed in a non-profit medical facility. Hhe operations were performed by 6 physicians and significant differences were found in the failure rates. In all instances the tissue removed proved to be vas deferens when examined histologically. Two factors seem to account for the differences of failure rates amoung the physicians; 1) the lenght of vas excised and 2) the character of thechnique. Phsicians with a high rate of success removed a significantly longer section of vas than physicians exhibiting higher failure rates. At least 15 mm. of vas should be excised to maximize the success of the procedure. Excised vas segments less than 15 mm. had up to a 25-fold greater incidence of failure. Although considered of secondary importance, good surgical technique subjectively measured by the minimal amount of accessory tissue attached to the excised vasa was also considered to aid in reducing the number of vasectomy failures.

Humans↗
PubMedDate not supplied

A study of underreporting of Down's syndrome on birth certificates in an Ohio County, 1970-78.

In a previous statewide assessment in Ohio of the percentage reporting of Down's syndrome (DS) on birth certificates, it was found that 33.9 percent of the cases chromosomally analyzed were so recorded. The objectives of this study were to gain a greater understanding of the basis of this low reporting percentage by concentrating on Hamilton County births only, to compare these percentages among hospitals in the county, and to determine the commonality of their causes. Since it was anticipated that both a thorough search of hospital records and access to chromosome analysis records would provide essentially complete ascertainment of DS births in the county during 1970-78, the data were also used to test the validity of chromosome analysis as a sampling procedure in estimating the total number of DS births by means of the Lincoln-Peterson capturerecapture method.The percentage of reporting of DS on the birth certificates by hospital ranged from 0.0 to 57.1, with a mean of 26.0 for the 6 hospitals within the county. Although variation among some hospitals was statistically significant, three of the six hospitals had zero percent reporting. The explanation for these low reporting percentages was fundamentally similar for all hospitals-a communications flow problem, produced by poor timing and use of the wrong sources of available information. The only data typically available to the birth certificate clerk were derived from the labor and delivery sheet, the form with the worst reporting percentage of DS of any in the medical record. On the other hand, by the time of discharge, 92.5 percent of the cases had either been definitely diagnosed as DS and were recorded on the face sheet or were entered as "chromosome analysis pending" in the file.The use of the chromosome analysis data gave an estimate of total DS births (N = 201 +/- 34) statistically consistent with the total observed, thereby providing support for this estimation procedure. Annual incidence rates for DS were also calculated for 1970-78, with a total incidence rate for the 9-year period of 1.14 per 1,000 live births.

Birth Certificates↗
PubMedDate not supplied

Evaluating false positives in two hospital discharge data sets of the Birth Defects Monitoring Program.

The principal goal in this study was to quantify false positives in the hospital discharge data of the Birth Defects Monitoring Program conducted by the Centers of Disease Control and Prevention. The two hospital data processing agencies which contribute data to the Birth Defects Monitoring Program, the Commission on Professional and Hospital Activities and the McDonnell Douglas Health Information Systems, had respective levels of false positives of 13.2 percent and 8.5 percent, levels which were statistically different from each other. These false positive levels should be considered minimal because these data bases do not include information on sick babies who may be transferred into or out of member hospitals, and who may have their initial diagnoses significantly modified. Potential correlates of false positives were evaluated, including hospital size, diagnostic certainty, race, sex, and insurance source. Two-thirds of all false positives were due to the miscoding of correctly diagnosed anomalies, and another quarter were clearly contradicted in notes easily available before the patients were discharged. The authors hope that this study of false positives will enhance the interpretation of the Birth Defects Monitoring Program data and lead to improved understanding of data collection and processing.

Centers for Disease Control and Prevention, U.S.↗