El laboratorio clínico y las dislipemias

Reference intervals of biochemical parameters in Chilean adults

Background

Establishing reference intervals (RIs) in clinical laboratories is essential, as these can vary due to inter-individual variability as well as the analytical methods used. The purpose of this study was to determine RIs for markers and ratios biochemical in apparently healthy Chilean adults.

Methods

A sample of 1,143 data was selected from the Universidad Católica de Temuco, Clinical Laboratory database, La Araucanía Region, Chile, which were analysed by sex. The Tukey's Fences was used to detect outliers and the RIs were established using the non-parametric method.

Characterization of lipid profile by nuclear magnetic resonance spectroscopy (1H NMR) of metabolically healthy obese women after weight loss with Mediterranean diet and physical exercise

Obesity is associated with an atherogenic lipid profile. No data exists on lipoprotein particle profiles in metabolically healthy obese (MHO) individuals. Our aim is to characterize lipoprotein size, particle, and subclass concentrations in MHO women after 3 months of weight loss through dietary restriction and physical exercise.A total of 115 nondiabetic women (aged 35-55 years) with a body mass index (BMI) of 30 to 40 kg/m and ≤1 of the following criteria: blood pressure ≤135/85 mm Hg, fasting plasma glucose ≤100 mg/dL, HDL-cholesterol ≤50 mg/dL, and triglycerides ≤150 mg/dL were included. After 3 months of intensive lifestyle modification (Mediterranean diet and physical exercise), they were classified according to their weight loss: <5%, ≥5% to <10%, and ≥10%. Lipoprotein size, particle, and subclass concentrations were measured using H NMR.The final sample, after dropouts, comprised 104 women (age: 44.4 ± 3.7 years, BMI: 36.3 ± 4.7 kg/m), of whom 47 (45.2%), 27 (26%), and 30 (28.8%) lost <5%, ≥5% to <10%, and ≥10% of baseline body weight, respectively. All participants experienced significant weight loss and decreases in BMI. The lipid profiles showed an increase in small, medium, and large very low density lipoprotein (VLDL) particles in all groups of study with the exception of small VLDL particles in women with ≥10% of weight loss, in which it decreased. The number of VLDL particles decreased in women who had ≥10% weight loss. On the other hand, we detected a decrease in all low density lipoprotein (cLDL) and high density lipoprotein (cHDL) concentrations.These results indicate that intensive lifestyle modification alters lipid profiles. In particular, it decreases small LDL and HDL particle numbers and does not increase medium or large HDL particles numbers.

[Advances in cholesterol-lowering interventions]

Numerous epidemiological and prospective studies have shown a direct relationship between total cholesterol and low-density lipoprotein cholesterol (LDL-C) and cardiovascular disease (cardiovascular morbidity and mortality). In many intervention studies with more than 100,000 subjects, statins have shown a powerful and significant reduction of cardiovascular events and a decrease in cardiovascular and overall mortality, far superior to those produced by any other lipid-lowering group. Consequently statins are considered to be safe and well tolerated and are the first choice in the treatment of hypercholesterolemia and in cardiovascular disease prevention. If targets are not reached, other pharmacological groups must be associated (resins, nicotinic acid, ezetimibe, fibrates, etc.). Moreover, when hypercholesterolemia is associated with low concentrations of high-density lipoprotein (HDL)-cholesterol and high triglyceride levels, the association of statins with nicotinic acid, fibrates or omega-3 should be considered. Some questions remain to be answered: what LDL-C levels are desirable in secondary prevention? Which individuals might benefit from treatment in primary prevention? Which lipid-lowering drug is the most suitable to combine with statins and diminish cardiovascular risk in each situation? The present article reviews these important points.