Factores de riesgo cardiovascular en Estados Unidos y México: comparación de los estudios HABLE y ENASEM / Cardiovascular risk factors in Mexico and the United States: a comparative cross-sectional study between the HABLE and MHAS participants

Resumen Introducción: En Estados Unidos se dispone de información acerca de la población mexicoamericana por el Estudio de Salud y Envejecimiento del Cerebro en Latinos Mayores (HABLE); en México se dispone de los resultados del Estudio Nacional de Salud y Envejecimiento en México (ENASEM). Objetivo: Comparar la prevalencia de factores de riesgo cardiovascular entre hombres y mujeres de HABLE y ENASEM. Método: Se analizó transversalmente la prevalencia de hipertensión, diabetes, hipercolesterolemia y obesidad abdominal en 559 participantes de HABLE y se comparó con datos de 13 663 participantes del ENASEM. La comparación se realizó mediante t de Student y chi cuadrada, según el tipo de variable. Resultados: El análisis demostró que la prevalencia de hipertensión (50 %, IC 95 % = 41.8-51.8), diabetes (35.5 %, IC 95 % = 27.6-43.8) y obesidad abdominal (59.3 %, IC 95 % = 50.5-68.1) fueron significativamente mayores en hombres del HABLE, mientras que las mujeres presentaron una prevalencia más elevada de diabetes (36.8 %, IC 95 % = 32.2-41.5) y obesidad abdominal (89.6 %, IC 95 % = 86.6-92.5). La hipercolesterolemia tuvo una prevalencia más elevada en mujeres del ENASEM (53.3 %, IC 95 % = 50.3-56.2). Conclusión: La prevalencia de factores de riesgo cardiovascular fue mayor en mexicoamericanos participantes del HABLE, que en mexicanos participantes del ENASEM.

Abstract Introduction: In the United States, information on the Mexican-American population is available through the Health and Aging Brain among Latino Elders (HABLE) study; in Mexico, the results of the Mexican Health and Aging Study (MHAS) are available. Objective: To compare the prevalence of cardiovascular risk factors between men and women of the HABLE and MHAS studies. Method: The prevalence of hypertension, diabetes, hypercholesterolemia and abdominal obesity was transversely analyzed in 559 HABLE participants and compared with data from 13,663 MHAS participants. The comparison was made using Student’s t-test and the chi-square test, according to the type of variable. Results: The analysis showed that the prevalence of hypertension (50 %, 95 % CI = 41.8-51.8), diabetes (35.5 %, 95 % CI = 27.6-43.8) and abdominal obesity (59.3 %, 95 % CI = 50.5-68.1) were significantly higher in HABLE males, whereas females had a higher prevalence of diabetes (36.8 %, 95 % CI = 32.2-41.5) and abdominal obesity (89.6 %, 95 % CI = 86.6-92.5). Hypercholesterolemia had a higher prevalence in MHAS females (53.3%, 95% CI = 50.3-56.2). Conclusion: The prevalence of cardiovascular risk factors was higher in Mexican American HABLE participants, than in Mexican MHAS participants.

High baseline serum total and LDL cholesterol levels are associated with MDR1 haplotypes in Brazilian hypercholesterolemic individuals of European descent

The MDR1 gene encodes the P-glycoprotein, an efflux transporter with broad substrate specificity. P-glycoprotein has raised great interest in pharmacogenetics because it transports a variety of structurally divergent drugs, including lipid-lowering drugs. The synonymous single-nucleotide polymorphism C3435T and the nonsynonymous single-nucleotide polymorphism G2677T/A in MDR1 have been indicated as potential determinants of variability in drug disposition and efficacy. In order to evaluate the effect of G2677T/A and C3435T MDR1 polymorphisms on serum levels of lipids before and after atorvastatin administration, 69 unrelated hypercholesterolemic individuals from São Paulo city, Brazil, were selected and treated with 10 mg atorvastatin orally once daily for four weeks. MDR1 polymorphisms were analyzed by PCR-RFLP. C3435T and G2677T polymorphisms were found to be linked. The allelic frequencies for C3435T polymorphism were 0.536 and 0.464 for the 3435C and 3435T alleles, respectively, while for G2677T/A polymorphism allele frequencies were 0.580 for the 2677G allele, 0.384 for the 2677T allele and 0.036 for the 2677A allele. There was no significant relation between atorvastatin response and MDR1 polymorphisms (repeated measures ANOVA; P > 0.05). However, haplotype analysis revealed an association between T/T carriers and higher basal serum total (TC) and LDL cholesterol levels (TC: 303 ± 56, LDL-C: 216 ± 57 mg/dl, respectively) compared with non-T/T carriers (TC: 278 ± 28, LDL-C: 189 ± 24 mg/dl; repeated measures ANOVA/Tukey test; P < 0.05). These data indicate that MDR1 polymorphism may have an important contribution to the control of basal serum cholesterol levels in Brazilian hypercholesterolemic individuals of European descent.

Screening for mutations in exons encoding the ligand-binding domain of the LDL receptor gene using PCR-CFLP and PCR-SSCP.

Primary hypercholesterolemia includes both monogenic disorders and polygenic conditions. Two well defined monogenic disorders are familial hypercholesterolemia (FH) and familial defective apolipoprotein (apo) B-100 (FDB). Both disorders convey high risk of premature coronary artery disease. FH and FDB are caused by mutations in LDL receptor and apo B-100 genes, respectively. In the present study, mutations in both genes in Thai subjects with primary hypercholesterolemia were screened. For apo B-100 gene, a common mutation R3500Q was screened. This mutation was not observed in the patients (n = 45). For LDL receptor gene, mutations in the exons encoding the ligand-binding domain were screened. By PCR-CFLP analysis, 18 abnormal CFLP patterns in exon 4, the hot spot for mutations, were found in patients (n=45). One of the DNA samples with abnormal CFLP patterns was previously identified and reported as a possible disease-causing mutation, namely D151Y. For the other exons, the screening technique was PCR-SSCP. Abnormal SSCP patterns in DNA samples from patients (n=20) were found as follows, two in exon 3, one in exon 5 and another one in exon 6. Further characterization by DNA sequencing and family studies for these abnormal patterns are underway.