Participation in organised sports does not slow declines in physical activity during adolescence.

Background: Among youth, participation in extracurricular physical activities at school and organised physical activities in the community is associated with higher physical activity levels. The objective was to determine if participation in organised physical activities during early adolescence protects against declines in physical activity levels during adolescence.

Methods: Every 3 months for 5 years, students initially in grade 7 (aged 12-13 years) completed a 7-day physical activity recall and provided data on the number and type of (extracurricular) physical activities organised at school and in the community in which they took part.

Customised birthweight percentiles: does adjusting for maternal characteristics matter?

Objective: The objective of this study was to determine whether the improved prediction of risk for perinatal mortality obtained with the use of a customised birthweight standard can also be obtained with the use of a non-customised but intrauterine-based standard.

Design: Population-based cohort study.

Setting: Sweden.

The impact of past pregnancy experience on subsequent perinatal outcomes.

In perinatal epidemiology, the basic unit of analysis has traditionally been the individual pregnancy. In this study, we sought to explore the idea of a 'reproductive life'-based approach to modelling the effects of reproductive exposures and outcomes, where the basic unit of analysis is a woman's entire reproductive experience. Our objective was to explore whether a first pregnancy risk factor, excess gestational weight gain, has a direct effect on the birthweight outcomes of a subsequent pregnancy, independent of the weight gain and other risk factors of the second pregnancy.

The missing data problem in birth weight percentiles and thresholds for "small-for-gestational-age".

Weight-for-gestational-age charts and definitions of "small-for-gestational-age" based on the distribution of livebirths at a given gestational age have conventionally been used to identify infants whose fetal growth is poor. However, references based on the weights of only livebirths have serious shortcomings at preterm ages due to missing data on the weights of fetuses still in utero, and these missing data introduce considerable bias to etiologic studies of fetal growth restriction. Application of standard epidemiologic approaches for missing data is needed to help produce perinatal weight percentiles that provide unbiased assessment of fetal growth and risks of small-for-gestational-age.

Is birth weight modified during pregnancy? Using sibling differences to understand the impact of blood glucose, obesity, and maternal weight gain in gestational diabetes.

Objective: The purpose of this study was to examine the extent to which blood glucose, obesity, and maternal weight gain explains differences in birth weight using offspring sibling pairs in gestational diabetes mellitus (GDM).

Study Design: A retrospective analysis of 90 women with at least 2 GDM pregnancies was conducted. A fixed effects model was used to examine differences between siblings of the same mother (within-women), and results were contrasted with a multivariable regression model that compared different mothers (between-women).

A comparative analysis of brain size in relation to foraging ecology and phylogeny in the Chiroptera.

Variations in total brain mass and in the mass of three brain regions (main olfactory bulb, hippocampus, auditory nuclei) were examined using a data set for 63 species of bats (Chiroptera). Using both conventional and phylogenetically based analysis of covariance (log body mass as covariate), we tested several hypotheses that relate total brain mass or the size of the components to variation in foraging ecology, categorized as phytophagous, gleaner, and aerial insectivore. In some analyses, the category phytophagous was split into phytophagous pteropodid and phytophagous phyllostomid to examine differences between two distinct clades of bats.

Total evidence, consensus, and bat phylogeny: A distance-based approach.

Resolution of the total evidence (i.e., character congruence) versus consensus (i.

Base-compositional biases and the bat problem. III. The questions of microchiropteran monophyly.

Using single-copy DNA hybridization, we carried out a whole genome study of 16 bats (from ten families) and five outgroups (two primates and one each dermopteran, scandentian, and marsupial). Three of the bat species represented as many families of Rhinolophoidea, and these always associated with the two representatives of Pteropodidae. All other microchiropterans, however, formed a monophyletic unit displaying interrelationships largely in accord with current opinion.