PubMed Health⌕ Search

Biomedical subjects

A C Hexter

Publications and source records attributed to A C Hexter.

18 recordsLinked to original sources
PubMed1991

Bias in congenital malformations information from the birth certificate.

An analysis of 1983 data from California birth certificates, and from the California Birth Defects Monitoring Program case registry, showed that there is a bias in reporting of congenital malformations on the birth certificate. Hospitals with many births erroneously report lower malformation rates than do hospitals with few births. The bias is partly due to the source of information; larger hospitals are more likely to get their information about malformations from the obstetrician than from the pediatrician. Since malformation data recorded on the birth certificate is both incomplete and biased, at present it is advisable to use these data for epidemiologic analyses with great caution.

Bias↗
PubMed1984

Repeatability of infant deaths in Korea.

Using data from the world fertility survey for Korea, repeatability of infant death in the family was investigated applying the log-linear model. There is a strong association in survivorship between any two consecutive births. No such association is observed in nonconsecutive birth orders. There is a suggestion however, that the survival of the first birth is related to that of the third or even the fourth birth order.

Birth Order↗
PubMed1981

A study on the effects of induced abortion on subsequent pregnancy outcome.

Presented here is the pregnancy outcome of 2,081 women who had one or more previous induced abortions compared with the outcome of 4,098 matched control subjects without a history of abortion. Data were collected from records and interviews of women delivering spontaneously at nine California hospitals during a 16-month period, 1976 to 1978. Women with a history of previous induced abortion showed a small but statistically significant increase in incidence of subsequent pregnancy failure. The increased risk associated with previous abortion was substantially smaller than the increase associated with several other social, economic, and behavioral indicators measured at the same time.

Abortion, Induced↗
PubMed1979

The risk of low birthweight.

Descriptive analyses of birthweight for single live births in the United States during 1974, using birth certificate information, show that several factors are associated with a high incidence of low birthweight babies. Multivariate analyses were performed to determine correlates of low birthweight. When other factors are held constant, race not white, previous reproductive loss, short interpregnancy interval, out-of-wedlock birth, no prenatal care, and maternal age under 18 years or over 35 years each increase the risk of having an infant of low birthweight. High birth order and maternal education under 12 years of schooling were not consistent risk factors for low birthweight. Odds ratios are presented and the method for combining these, to estimate the risk for an individual mother having a low-birthweight infant, is illustrated.

Birth Order↗
PubMed1977

Effects of DDT on reproduction in multiple generations of beagle dogs.

The effects of chronic oral exposure to 1, 5, and 10 mg of technical DDT/kg/day on: 1) age at puberty, length of gestation, fertility, success of pregnancy, litter size, and lactational ability of dams; 2) viability, survival to weaning, sex distribution and growth of pups; and 3) morbidity, mortality, organ/body weight ratios, gross and histologic abnormalities in all animals were studied through three generations of Beagle dogs. There were a total of 135 adult female and 63 adult male dogs in the project which produced 650 pups. There were no statistically significant differences among control and DDT-treated dogs in any of the reproductive variables, with the exception of age at puberty of the females. DDT-treated females had their first estrous cycles 2 to 3 months earlier (P less than .001) than the control dogs. Selected DDT-treated females, held for a second breeding period, had normal anestrous periods between their first and second estrous cycles. There was no effect of DDT on survival, growth, and sex distribution of pups, nor was there any influence on morbidity, mortality, gross or histologic findings in any of the dogs. All organ/body weight ratios were normal, with the possible exception of an increase in liver/body weight ratio in some DDT-treated animals.

Animals↗
PubMed1971

Carbon monoxide: association of community air pollution with mortality.

Regression analysis of daily mortality in Los Angeles County shows that there is a significant association between community carbon monoxide concentrations and mortality. Cyclic variation and maximum temperature were the main contributors. No association was demonstrated between oxidant and mortality.

Air Pollution↗
PubMed1967

Respiratory exposure to lead: epidemiological and experimental dose-response relationships.

Epidemiologic studies of blood lead levels in general and occupational groups show a logarithmic regression on estimated atmospheric exposure. Experimental results at the same and higher levels show a dose-response relationship which fits the same regression. The data imply that long-term increases in atmospheric lead will result in predictably higher blood lead levels in the exposed populations.

Adenosine Triphosphatases↗
PubMedDate not supplied

Evaluation of the hospital discharge diagnoses index and the birth certificate as sources of information on birth defects.

The hospital discharge diagnoses index (DI) for newborns and the birth certificate were evaluated as sources of information about birth defects by comparing them with the same births in the case registry of the California Birth Defects Monitoring Program (CBDMP). The CBDMP is an active surveillance system; the staff visit hospitals to identify children with birth defects diagnosed in the first year of life. The study population comprised 66,481 live births to residents of five counties in the San Francisco Bay area in 1983. Of these infants, 2,543 had at least one birth defect noted on the DI, and 1,623 were in the CBDMP registry; 1,020 with defects noted on the DI were also in the CBDMP registry. For this same population, 399 infants had one or more defects noted on the birth certificate; 304 of these were also in the CBDMP registry. Reporting of birth defects on the birth certificate was poor for every condition. Reporting on the DI was most reliable for oral clefts and chromosomal defects; for these defects, the DI omitted one-third of the cases but had identified only about 10 percent false-positive (that is, unverified) cases. Major central nervous system malformations were less well reported, with about one-third of them false-positive. For all other birth defects, the DI either omitted more than half of the cases, or more than half of the cases reported were false-positive cases. These findings raise questions about the validity of analytic studies of birth defects if the data are obtained only from the DI or the birth certificate.

Birth Certificates↗