Biomedical subjects

Hae-Hiang Song

Publications and source records attributed to Hae-Hiang Song.

4 recordsLinked to original sources

PubMed2006

Nonparametric trend statistic incorporating dispersion differences in sib pair linkage for quantitative traits.

The Haseman-Elston (HE) regression method and its extensions are widely used in genetic studies for detecting linkage to quantitative trait loci (QTL) using sib pairs. The principle underlying the simple HE regression method is that the similarity in phenotypes between two siblings increases as they share an increasing number of alleles identical by descent (IBD) from their parents at a particular marker locus. In such a procedure, similarity was identified with the locations, that is, means of groups of sib pairs sharing 0, 1, and 2 alleles IBD. A more powerful, rank-based nonparametric test to detect increasing similarity in sib pairs is presented by combining univariate trend statistics not only of locations, but also of dispersions of the squared phenotypic differences of two siblings for three groups. This trend test does not rely on distributional assumptions, and is applicable to the skewed or leptokurtic phenotypic distributions, in addition to normal or near normal phenotypic distributions. The performances of nonparametric trend statistics, including nonparametric regression slope, are compared with the HE regression methods as genetic linkage strategies.

Computer Simulation↗

PubMed2004

Risk factors for falls among the community-dwelling elderly in Korea.

Community-based centres were surveyed to determine the frequency of and risk factors for falls among elderly Koreans. We examined fall-related risk factors, including physiological and physical health, psychosocial functions, self-reported physical capacity and activity, vision, and the use of medication, among 351 elderly people aged 65 years or older, with ambulatory. Forty-two per cent of elderly Korean subjects reported at least one episode of falling in the previous 12 months, 38% of whom had consequences that required either the attention of a physician or hospitalization. Factors significantly associated with an increased risk of falling were a restricted activity during the previous five years (adjusted OR 1.3), use of alternative therapy (adjusted OR 2.7), low knee flexor and extensor-muscle strength (adjusted OR 1.21 and 1.20), and poor balance with closed eyes (adjusted OR 8.32). We conclude that falls among older persons living in the community are common in Korea and that indicator of bad health and frailty or variables directly related to neuromuscular impairment are significant predictors of the risk of falling.

Accidental Falls↗

PubMed2003

Fall prevention exercise program for fall risk factor reduction of the community-dwelling elderly in Korea.

A randomized comparison of pre-and post-experimental design was used to examine the effects of a fall prevention exercise program (FPEP) on muscle strength, ankle flexibility, balance, instrumental activities of daily living (IADLs), and depression for the community-dwelling elderly in Korea. Twenty-two subjects were assigned to an experimental group and twenty-three to a control group. The experimental group participated in a 4-day-per week FPEP of 8 weeks duration, twice a week by direct instruction and twice a week with videotaped instruction by the program instructor at each senior center. The eight-week FPEP turned out to be significantly effective in enhancing muscle strength, ankle flexibility and balance, and in reducing depression, after intervention among community-dwelling elderly in Korea. IADLs, however, was not changed by the intervention. Further research with a larger sample and longer follow up period is needed to expand our understanding about the effects of FPEP. Future study is also recommended to differentiate between the effects of FPEP by direct instruction and by videotaped.

Accidental Falls↗

PubMed2003

Statistical inference methods for detecting altered gene associations.

The higher incidence of liver disease in the Asian population raises a great concern to clinicians. To understand the gene functions involved in different stages of the disease, microarray expression data of histological progressive grades, starting from the dysplastic nodule in cirrhotic liver to hepatocellular carcinoma Edmonson grade III are analyzed. The statistical procedures are divided into two parts: First, microarray data are suitably normalized, including a method of analysis of variance (ANOVA). There are great differences of opinion regarding the currently used normalization methods. In order to proceed to the second part of statistical analyses of gene-pair associations, these normalization methods need first to be compared. Based on the assumption that a union set of significant genes from these normalization methods includes sufficiently general and well-defined, differentially expressed genes, one must carry out the second part of statistical analyses of searching for evidence of altered gene-gene relationships with progression of the disease. Significantly altered gene-pair associations are identified with the ratio of gene-pair correlations. The methods are illustrated with replicated microarray expression data.

Analysis of Variance↗