Genetic variants associated with fasting blood lipids in the U.S. population: Third National Health and Nutrition Examination Survey

<p>Abstract</p> <p>Background</p> <p>The identification of genetic variants related to blood lipid levels within a large, population-based and nationally representative study might lead to a better understanding of the genetic contribution to serum lipid levels in the major race/ethnic groups in the U.S. population.</p> <p>Methods</p> <p>Using data from the second phase (1991-1994) of the Third National Health and Nutrition Examination Survey (NHANES III), we examined associations between 22 polymorphisms in 13 candidate genes and four serum lipids: high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), and triglycerides (TG). Univariate and multivariable linear regression and within-gene haplotype trend regression were used to test for genetic associations assuming an additive mode of inheritance for each of the three major race/ethnic groups in the United States (non-Hispanic white, non-Hispanic black, and Mexican American).</p> <p>Results</p> <p>Variants within <it>APOE </it>(rs7412, rs429358), <it>PON1 </it>(rs854560), <it>ITGB3 </it>(rs5918), and <it>NOS3 </it>(rs2070744) were found to be associated with one or more blood lipids in at least one race/ethnic group in crude and adjusted analyses. In non-Hispanic whites, no individual polymorphisms were associated with any lipid trait. However, the <it>PON1 </it>A-G haplotype was significantly associated with LDL-C and TC. In non-Hispanic blacks, <it>APOE </it>variant rs7412 and haplotype T-T were strongly associated with LDL-C and TC; whereas, rs5918 of <it>ITGB3 </it>was significantly associated with TG. Several variants and haplotypes of three genes were significantly related to lipids in Mexican Americans: <it>PON1 </it>in relation to HDL-C; <it>APOE </it>and <it>NOS3 </it>in relation to LDL-C; and <it>APOE </it>in relation to TC.</p> <p>Conclusions</p> <p>We report the significant associations of blood lipids with variants and haplotypes in <it>APOE</it>, <it>ITGB3, NOS3</it>, and <it>PON1 </it>in the three main race/ethnic groups in the U.S. population using a large, nationally representative and population-based sample survey. Results from our study contribute to a growing body of literature identifying key determinants of plasma lipoprotein concentrations and could provide insight into the biological mechanisms underlying serum lipid and cholesterol concentrations.</p

Seawater intrusion in the Guanahacabibes Peninsula (Pinar del Rio Province, western Cuba): effects on karst development and water isotope composition

The water resources in the Guanahacabibes Peninsula are distributed in two areas. The northeastern area is characterized by swamps, wetlands and lagoons, with a low contribution of seawater, whereas the area in the southwestern plain shows a considerable development of the karst structures that limits the existence of superficial waters but permits the ingression of the surrounding seawater. In this latter area, the groundwater showed a marked increase in salinity with the depth. In particular, groundwater with a seawater fraction of 0.1 had the lowest Ca-(Mg)-carbonates saturation indexes calculated by modeling the mixing between freshwater and seawater using different software, thermodynamic databases and equations for activity coefficients. Generally, seawater and groundwaters with an added seawater fraction above 0.60–0.65 showed similar oversaturated indexes in high-Mg calcites and pure Ca-carbonates (calcite and aragonite). Differently, in the groundwater that showed carbonates undersaturation (generally with a seawater fraction between 0.02 and 0.60), the saturation indexes in high-Mg calcites were 0.2 lower than pure Ca-carbonates. Locally, the bacterial reduction of the dissolved sulfate enhanced the dissolution of the limestone, contributing to the increased development of the karst structures and the seawater intrusion. Finally, the presence near the coastline of fresh Ca- and Na-bicarbonate waters was in accordance with the upward flow of the shallow freshwater during the formation of the saline wedge. However, the oxygen and hydrogen stable isotope composition of the waters showed a probable contribution to the area from a deep aquifer that is recharged in the highest reliefs of the province (Cordillera de Guaniguanico)