Determination of adjusted reference intervals of urinary biomarkers of oxidative stress in healthy adults using GAMLSS models.

In this study we aimed at identifying main demographic, laboratory and environmental factors influencing the level of urinary biomarkers (DNA-derived 8-oxodG and lipid membrane-derived 8-isoprostane), and deriving their adjusted 95% reference intervals (RI) in a sample of healthy people from the general population. Data from 281 healthy subjects from the Gene Environment Interactions in Respiratory Diseases survey were used in this study. Generalized additive models for location, scale and shape (GAMLSS) were used to find determinants of the biomarkers among gender, age, season and distance from collection (DFC), and to predict their RI. The RI of the biomarkers stratified by season and adjusted for DFC showed a slight statistically significant decrease in the biomarkers at the increasing DFC in two seasons, except the 8-oxodG during the warm season: median levels at the min and max values of DFC were (ng/mgcreat) 7.0-1.1 in the cold and 3.9-3.9 in the warm seasons for 8-oxodG, 0.7-0.2 in the cold and 1.3-0.6 in the warm seasons for 8-isoprostane. Both the biomarkers should be evaluated in association with the DFC and season in large epidemiological studies. The (semi)parametric GAMLSS method is a useful and flexible technique, which makes it possible to estimate adjusted RI.

Gross motor coordination and weight status of Portuguese children aged 6-14 years.

OBJECTIVES: To construct age- and gender-specific percentiles for gross motor coordination (MC) tests and to explore differences in gross MC in normal-weight, overweight and obese children. METHODS: Data are from the "Healthy Growth of Madeira Study," a cross-sectional study carried out in children, aged 6-14 years. All 1,276 participants, 619 boys and 657 girls, were assessed for gross MC (Körperkoordinations Test für Kinder, KTK), anthropometry (height and body mass), physical activity (Baecke questionnaire) and socioeconomic status (SES). Centile curves for gross MC were obtained for boys and girls separately using generalized additive models for location, scale and shape. RESULTS: A significant main effect for age was found in walking backwards and moving sideways. Boys performed significantly better than girls on moving sideways. At the upper limit of the distributions, interindividual variability was higher in hopping on one leg (girls) and jumping and moving sideways (boys and girls). One-way ANCOVA, controlling for age, physical activity and SES, indicated that normal-weight children scored significantly better than their obese peers in all gross MC tests. Overweight boys and girls also scored significantly better than their obese colleagues in some MC tests. CONCLUSIONS: These centile curves can be used as reference data in Portuguese children and youth, aged 6-14 years. Being overweight or obese was a major limitation in MC tests and, therefore, of the children's health- and performance-related physical fitness.