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Biomedical subjects

T W Pullum

Publications and source records attributed to T W Pullum.

16 recordsLinked to original sources
PubMed1996

A follow-up study of first trimester induced abortions at hospitals and family planning clinics in Sichuan province, China.

Four-thousand women aged 18-40 underwent an early induced abortion at hospitals and family planning clinics in six counties in Sichuan province, China, between 1 July 1990 and 30 June 1991. The subjects were followed-up three times, on days 15, 90 and 180 after the operation. Information was obtained about their age, parity, contraceptive use, social behaviors, and gynecological and psychological characteristics before and after the abortion. The results indicate that induced abortion is safe when provided by medically trained personnel in health facilities such as hospitals or clinics. Depressive symptomatology was assessed by the CES-D and SCL-90 scales. The depressive symptoms declined over time. A substantial proportion of the abortions were to unmarried women or resulted from non-use of contraception or contraceptive failure, implying that the incidence of unintended pregnancies and induced abortions could be reduced by more effective and accessible contraception.

Abortion, Induced↗
PubMed1995

Induced abortion among unmarried women in Sichuan province, China.

This report describes the social and demographic characteristics of 457 unmarried women who underwent a first trimester induced abortion at hospitals and family planning clinics in Sichuan province, China. The data show a very low level of medical complications. However, improved access to contraception for unmarried women is needed in order to reduce the incidence of unintended pregnancies and induced abortion.

Abortion, Induced↗
PubMed1991

Statistical methods to adjust for date and age misreporting to improve estimates of vital rates in Pakistan.

Misreporting of dates and ages poses serious difficulties for the estimation of the age distribution and birth and death rates in many developing countries. The pervasiveness of these problems is illustrated with data from a well-designed on-going survey in Pakistan, the Pakistan Demographic Survey. Methods for reconciling discrepancies, based on the assumptions of constant misreporting and survivorship patterns, are presented. The reasoning behind these methods could be applied much more generally. Research into the cultural interpretations of age and dates, and the nature of possible biases, is called for.

Birth Rate↗
PubMed1991

Correlations between frequencies of kin.

Recent years have seen the development of formal and microsimulation models of the structure and dynamics of kin networks. These models generally assume uncorrelated fertility within and across generations. Several sets of real data, however, show positive correlations between the frequencies of various categories of kin. This paper uses formal models to calculate the correlations that will exist between certain categories of kin even if mothers and daughters have independent fertility. Mechanisms by which fertility might be transmitted from mothers to their daughters are considered and the implications for kin correlations are evaluated.

Adolescent↗
PubMed1989

Measuring change and continuity in parity distributions.

Procedures are developed to allocate the change in mean fertility to the change in specific parities or groups of parities. One procedure uses the proportion at each parity and another uses parity progression ratios. Both are based on the delta method for approximating change in a function of several variables. Drawing on an analogy to survival in a life table, the relational logit model is applied to parity progression. This method allows several parity distributions to be synthesized and to have differences summarized with two parameters. The three procedures are applied to successive cohorts of white U.S. women who completed their childbearing between 1920 and 1980.

Cohort Studies↗
PubMed1983

Population estimates from longitudinal records in otherwise data-deficient settings.

Existing methods for estimating population parameters in settings of data deficiency do not provide techniques for analysis of commonly available longitudinal data. In setting where complete population data is unavailable, longitudinal data recorded for only a subset of the total population are often available (e.g., event registers, genealogies). In this article we present and evaluate models which derive population parameters for the population subgroup underlying such longitudinal data. Using the distribution of individual times until first recorded event within a measurement interval, population parameters are estimated which provide basic denominator data for analyzing event occurrence. The models which we derive are especially suited to records which may include migration and population growth trends. The use of the models is demonstrated and evaluated through an application to genealogical records for a nineteenth-century population. Possible extensions of these models and their major limitations are also discussed.

Adult↗
PubMed1982

The eventual frequencies of kin in a stable population.

Associated with every real birth cohort of women is a set of probabilities [fk] of eventually having k daughters. With a variant of stable population theory, these probabilities are used to generate the entire probability distributions, as well as all moments, for all categories of skin who are female and female-related. With additional assumptions, a full two-sex model for all kin also is given. The two-sex model is applied to a cohort of U.S. women born in the mid-twentieth century, suggesting plausible frequencies of kin in a stationary population.

Adult↗
PubMed1977

Path analysis: application in an epidemiological study of echinococcosis in New Zealand.

The method of path analysis is described in detail. Application of this analyogical systems is demonstrated using data from an epidemiological study of echinococcosis in New Zealand. The results identified the major causal pathways determining Echinococcus granulosus prevalence in dogs, based on multiple regression analysis of a linear causal model constructed from prior biological and epidemiological knowledge. Only ethnic and sheep husbandry variables had important direct effect on prevalence in the North Island of New Zealand, with some climate factors (maximum temperature and relative humidity) and soil porosity acting indirectly through animal husbandry practices. It is suggested that path analysis, by permitting interaction between epidemiological theory and statistical analysis, provides a valuable additional tool to epidemiologists for the study of causal relationships among variables in multivariates systems.

Animals↗
PubMed1977

A vital statistics-based procedure for estimating conception rates.

A method for estimating conception rates, using vital statistics data, is developed and applied to data on five-year age groups of California women for 1971. The approach is deterministic and allocates total exposure time to the known pregnancy outcomes of live birth, spontaneous abortion, and induced abortion. The population at risk is defined to exclude women who are known to be sterile or sexually inactive. Early fetal loss, premarital conception, and contraceptive use are taken into account. Estimates are made of the fecundability which would obtain if no contraception were used.

Abortion, Induced↗