Sex-related differences in aging rate are associated with sex chromosome system in amphibians.

Sex-related differences in mortality are widespread in the animal kingdom. Although studies have shown that sex determination systems might drive lifespan evolution, sex chromosome influence on aging rates have not been investigated so far, likely due to an apparent lack of demographic data from clades including both XY (with heterogametic males) and ZW (heterogametic females) systems. Taking advantage of a unique collection of capture-recapture datasets in amphibians, a vertebrate group where XY and ZW systems have repeatedly evolved over the past 200 million years, we examined whether sex heterogamy can predict sex differences in aging rates and lifespans.

Postneonatal mortality in Alabama: why no progress in the 90s?

Purpose: To examine the factors associated with postneonatal mortality.

Methods: Logistic regression was used to examine the effects of various variables on postneonatal mortality in Alabama.

Results: The most important predictor of postneonatal mortality was birth weight.

Low prenatal weight gain among adult WIC participants delivering term singleton infants: variation by maternal and program participation characteristics.

Objective: To determine the association of maternal and prenatal WIC program participation characteristics with low prenatal weight gain among adult women delivering liveborn, singleton infants at term.

Methods: WIC program data for 19,017 Black and White Alabama women delivering in 1994 were linked with birth certificate files to examine the association of anthropometric, demographic, reproductive, hematologic, behavioral and program participation characteristics with low prenatal weight gain.

Results: One third (31.

Improving medical risk factor reporting on birth certificates in Alabama.

Background: In 1995, a program was begun at the University of South Alabama (USA) to improve the reporting of medical risk factors on birth certificates.

Methods: Data on medical risk factors for USA Hospital and the remainder of the state for 1994 and 1996 were examined to observe the effects of the USA Medical Center program.

Results: The number of medical risk factors reported changed markedly between 1994 and 1996 for most items and changed hardly at all for the remainder of the state.

Why is the cesarean delivery rate so high in Alabama? An examination of risk factors, 1991-1993.

Background: Cesarean delivery is now the most frequently performed major operative procedure for childbearing women in the United States. Many of these operations are reported to be unnecessary, and millions of dollars could be saved by reducing their frequency.

Methods: Method of delivery was added to the 1989 revision of the standard certificate of live birth.

The revised standard certificate of live birth: analysis of medical risk factor data from birth certificates in Alabama, 1988-92.

The latest revision of the birth certificate features a new checkbox format designed to collect more effectively information for public health research. One of the new checkbox items, medical risk factors for this pregnancy, is designed to collect information on risk factors which result in adverse pregnancy outcomes. Data from 308,573 birth certificates filed in Alabama between 1988 and 1992 were analyzed.