The effect of genetic admixture in an association study: genetic polymorphisms and chromosome aberrations in a Colombian population exposed to organic solvents.

The human population is heterogeneous in genetic susceptibility, chromosomal instability and disease risk; all factors which depend on inherited genetic constitution and acquired nongenetic environmental and occupational factors. Recently, special attention has been directed to the identification of sources of potential bias in population studies of gene-environment interactions including genetic admixture. The aim of this study was to evaluate the effect of genetic admixture in the association of genetic polymorphisms and chromosome aberrations (CA) in a population exposed to organic solvents. We assessed genetic admixture via 34 genetic ancestry informative markers (AIMs) in 398 Colombian individuals. We report a statistically significant difference of higher CA frequency in individuals' below-average European component, and in individuals' above-average Native American component after adjusting for covariates. In addition, the confounding risk ratio values are ≥10% than the adjusted risk ratio, suggesting that population stratification is a confounding factor in this gene-environment association study. Furthermore, after adjusting for individual admixture proportions and covariates, the results demonstrate that glutathione-S-transferase M1 (GSTM1)-null is associated with CA frequency increase. These results suggest that gene-environment association studies that involve recently admixed populations should take into consideration population stratification as a confounding factor and suggest GSTM1-null as a genetic marker associated with CA frequency increase.

Parámetros biométricos oculares en candidatos a cirugía de catarata / Ocular biometric parameters in cataract surgery candidates

Introducción: Las estructuras ópticas pueden variar en su configuración y medida dependiendo de la edad, el sexo y la raza, por lo que su medición previa a la cirugía es un pilar fundamental para el cálculo correcto del lente intraocular. Caracterizar los rangos normales de estos parámetros en nuestra población suministra información importante que puede mejorar los resultados visuales tras la cirugía de catarata y alertar en aquellos casos que distan de la media de los rangos conocidos. Objetivo: Describir los parámetros biométricos oculares en pacientes candidatos a cirugía de catarata y analizar sus variaciones según la edad y el sexo. Método: Estudio observacional descriptivo, de corte transversal. Análisis retrospectivo de biometrías oculares realizadas con reflectometría óptica de baja coherencia en pacientes candidatos a cirugía de catarata. Resultados: Se evaluaron 820 ojos de 820 pacientes candidatos a cirugía de catarata, con una edad media de 68.1 ± 11.1 años, el 53.7% de sexo femenino. Los parámetros oculares promedios encontrados fueron: longitud axial (AL) 23.39 ± 1.11 mm, profundidad de cámara anterior (ACD) 3.37 ± 0.49 mm, astigmatismo corneal (AST) 1.09 ± 0.85 D, espesor corneal central (CCT) 529.43 ± 35.02 µm, poder queratométrico (K) 43.81 ± 1.64 D, queratometría plana 43.28 ± 1.69 D, queratometría curva 44.37 ± 1.74 D y distancia blanco a blanco 11.82 ± 0.52 mm. El promedio de AL y ACD fue mayor en los hombres que en las mujeres (p < 0.0001), y con el aumento de la edad el AST y el K mostraron una tendencia al incremento. Se encontró un 23.78% de astigmatismo con la regla, un 54.88% de astigmatismo contra la regla y un 21.34% de astigmatismo oblicuo. Conclusiones: El perfil de los datos biométricos evidenció diferencias significativas entre sexos y grupos de edad. Se encontró una buena correlación entre la AL, la ACD y la potencia corneal, y los promedios encontrados se corresponden bien con los de otras poblaciones de similar origen étnico.

Introduction: Optical structures can vary in their configuration and measurement depending on age, sex and race, so their measurement, prior to surgery, is a fundamental pillar for the correct calculation of the intraocular lens. Characterizing the normal ranges of these parameters in our population provides important information that can improve the visual results of cataract surgery and alert in those cases that are far from the mean of the known ranges. Objective: To describe the ocular biometric parameters in cataract surgery candidates. Method: Descriptive, cross-sectional study. Retrospective analysis of biometric parameters measured by optical low-coherence reflectometry in cataract surgery candidates. Results: The study evaluated 820 eyes of 820 cataract patients, the mean age was 68.1 ± 11.1 years, 53.7% female. Mean ocular parameters found were: axial length (AL) 23.39 ± 1.11 mm, anterior chamber depth (ACD) 3.37 ± 0.49 mm, corneal astigmatism (AST) 1.09 ± 0.85 D, central corneal thickness (CCT) 529.43 ± 35.02 µm, keratometry (K) 43.81 ± 1.64 D, flat keratometry (K1) 43.28 ± 1.69 D, steep keratometry (K2) 44.37 ± 1.74 D and white-to-white distance (WTW) 11.82 ± 0.52 mm. Mean AL and ACD were significantly longer in men (p < 0.0001) and with increasing age, AST and K showed an upward trend. 23.78% of astigmatism with the rule, 54.88% of astigmatism against the rule and 21.34% of oblique astigmatism were found. Conclusions: The profile of the biometric data showed significant differences between sex and age groups, a good correlation was found between axial length, chamber depth and keratometry. The averages found correspond well to those of other populations of similar ethnic origin