Biomedical subjects

Mulugeta Gebregziabher

Publications and source records attributed to Mulugeta Gebregziabher.

3 recordsLinked to original sources

PubMed2006

Risk patterns of multiple myeloma in Los Angeles County, 1972-1999 (United States).

OBJECTIVE: To describe the risk patterns of multiple myeloma in Los Angeles County (LAC). METHODS: Incident multiple myeloma cases diagnosed from 1972 to 1999 were ascertained by the population-based cancer registry for LAC. Average annual age-specific and age-adjusted incidence rates (AAIR), standardized to the 2000 US census age distribution, were calculated using age-, race-, sex- and socioeconomic status (SES)-specific denominators estimated for all years from US census data for 1970, 1980 and 1990. Odds ratios (ORs) for risk by birthplace and religion were estimated using multivariate logistic regression, comparing multiple myeloma patients with other cancer patients. RESULTS: All groups experienced increasing incidence with age; African-Americans experienced the steepest increase which began a decade earlier compared to other groups. Overall incidence rates were 50% higher among males (n = 4,692) than females (n = 4,343) (p < 0.05). AAIRs were highest for African-Americans, followed by Spanish-surnamed whites (SSW), non-Spanish-surnamed whites (NSSW), Filipinos and other Asian groups. Among African-Americans, incidence rates increased with increasing SES. US-born SSW had 14% lower risk compared to non-US born SSW (OR = 0.86, 95% confidence interval [CI] = 0.74-0.99]. Jews had an 11% higher risk compared to Protestants (OR = 1.11; 95% CI = 0.99-1.24). CONCLUSION: Risk patterns suggest a role for both environmental and genetic factors.

Adolescent↗

PubMed2006

Interleukin-6-related genotypes, body mass index, and risk of multiple myeloma and plasmacytoma.

Interleukin-6 (IL-6) promotes normal plasma cell development and proliferation of myeloma cells in culture. We evaluated IL-6 genotypes and body mass index (BMI) in a case-control study of multiple myeloma and plasmacytoma. DNA samples and questionnaires were obtained from incident cases of multiple myeloma (n = 134) and plasmacytoma (n = 16; plasma cell neoplasms) ascertained from the Los Angeles County population-based cancer registry and from siblings or cousins of cases (family controls, n = 112) and population controls (n = 126). Genotypes evaluated included IL-6 promoter gene single nucleotide polymorphisms (SNP) at positions -174, -572, and -597; one variable number of tandem repeats (-373 A(n)T(n)); and one SNP in the IL-6 receptor (IL-6ralpha) gene at position -358. The variant allele of the IL-6 promoter SNP -572 was associated with a roughly 2-fold increased risk of plasma cell neoplasms when cases were compared with family [odds ratio (OR), 1.8; 95% confidence interval (95% CI), 0.7-4.7] or population controls (OR, 2.4; 95% CI, 1.2-4.7). The -373 9A/9A genotype was associated with a decreased risk compared with the most common genotype (OR for cases versus family controls, 0.4; 95% CI, 0.1-1.7; OR for cases versus population controls, 0.3; 95% CI, 0.1-0.9). No other SNPs were associated with risk. Obesity (BMI >or= 30 kg/m(2)) increased risk nonsignificantly by 40% and 80% when cases were compared with family controls or population controls, respectively, relative to persons with a BMI of <25 kg/m(2). These results suggest that IL-6 promoter genotypes may be associated with increased risk of plasma cell neoplasms.

Adult↗

PubMed2004

Two-Stage sampling designs for gene association studies.

We consider two-stage case-control designs for testing associations between single nucleotide polymorphisms (SNPs) and disease, in which a subsample of subjects is used to select a panel of "tagging" SNPs that will be considered in the main study. We propose a pseudolikelihood [Pepe and Flemming, 1991: JASA 86:108-113] that combines the information from both the main study and the substudy to test the association with any polymorphism in the original set. SNP-tagging [Chapman et al., 2003: Hum Hered 56:18-31] and haplotype-tagging [Stram et al., 2003a; Hum Hered 55:27-36] approaches are compared. We show that the cost-efficiency of such a design for estimating the relative risk associated with the causal polymorphism can be considerably better than for a single-stage design, even if the causal polymorphism is not included in the tag-SNP set. We also consider the optimal selection of cases and controls in such designs and the relative efficiency for estimating the location of a causal variant in linkage disequilibrium mapping. Nevertheless, as the cost of high-volume genotyping plummets and haplotype tagging information from the International HapMap project [Gibbs et al., 2003; Nature 426:789-796] rapidly accumulates in public databases, such two-stage designs may soon become unnecessary.

Case-Control Studies↗