Influences of sex and age on biological rhythms of serum lipids and lipoproteins.

Background: Few studies have evaluated seasonal variations of biochemical parameters routinely analyzed in clinical laboratories. Rhythmic patterns for lipids and lipoproteins have been demonstrated and have been the object of research, mainly because of their demonstrated association with coronary artery disease. This study evaluated the occurrence of biological rhythms on serum lipids and lipoproteins and the effects of sex and age on the rhythms in a Brazilian hospital outpatient population.

The use of a hospital laboratory cohort to estimate the prevalence of dyslipidemia in an adult Brazilian population.

Background: Dyslipidemia is diagnosed through the determination of plasma lipid profiles. This study is aimed at establishing the prevalence of dyslipidemia in a Brazilian out-patient population by using a hospital laboratory cohort.

Methods: Lipid profiles of 22,542 individuals from both sexes, aged 20 to 124 years, and registered at the University Hospital of the State University of Campinas, a standard of reference for hospital treatment in the state of São Paulo, Brazil, were retrospectively analyzed from 2000 to 2003.

Biological rhythms of biochemical serum parameters in a Brazilian population: a three-year study.

A marked decrease in analytical and post-analytical variability has been achieved in clinical laboratories by the use of automated analytical systems. Current studies are now focused on the origin of pre-analytical variability, such as that due to intra-individual differences and biological rhythms. The objective of this work was to evaluate the occurrence of biological rhythms in several biochemical serum parameters in a Brazilian population.