Genetic influence on serum 25-hydroxyvitamin D concentration in Korean men: a cross-sectional study

Abstract Background Hypovitaminosis D is prevalent worldwide. It is more prevalent in Eastern Asia region, including Korea. In addition to various environmental factors that influence serum 25-hydroxyvitamin D (25(OH)D) concentration, genetic influence also plays a significant role based on studies estimating the heritability of 25(OH)D in non-Asian populations. The objective of this study was to determine the genetic influence on serum 25(OH)D concentration in Korean men using the twin and family data. Methods A total of 1126 Korean male adult twins and family members from the Healthy Twin Study with serum 25(OH)D measurement were included in this cross-sectional study. Intraclass correlation coefficients (ICCs) and heritability were calculated by mixed linear regression analysis and quantitative genetic analysis after adjusting for environmental and lifestyle factors. Results Mean (± standard deviation; SD) of serum 25(OH)D concentration was 15.34 ± 6.18 ng/ml. The prevalence of vitamin D insufficiency was 19.8% and that of vitamin D deficiency was 77.9%. After adjusting for age, the highest ICC (0.61) was observed for monozygotic twin pairs while the lowest ICC (0.31) was found for father-son pairs. Age-adjusted heritability was estimated to be 58%. When physical activity, multivitamin intake and season of blood sampling were further considered, the ICC and heritability did not materially change. In the sensitivity analysis after excluding known multivitamin users, age-adjusted heritability was reduced to 44%. Conclusions In our study of Korean male twins and family members, heritability of 25(OH)D was moderately high. This supports the finding that genetic factors have significant influence on vitamin D status

Validation study for the Korean version of Fear of Cancer Recurrence Inventory

Fear of cancer recurrence (FCR) is one of the most prevalent unmet psychosocial needs. This study aimed to confirm the cultural equivalence, reliability, and validity of the Korean version of Fear of Cancer Recurrence Inventory (K-FCRI). We conducted a forward–backward translation of the English version FCRI to Korean version through meticulous process including transcultural equivalence test. The psychometric property of the K-FCRI was then validated in 444 survivors from cancers at various sites. The Korean translation was accepted well by participants. There was a good cultural equivalence between the Korean version and the English version of FCRI. Confirmatory factor analysis supported the original seven-factor structure with slightly insufficient level of goodness-of-fit indices (comparative fit index = 0.900, non-normed fit index = 0.893, root mean square error of approximation = 0.060). The K-FCRI had high internal consistency (α = 0.85 for total scale and α = 0.77–0.87 for subscales) and test-retest reliability (r = 0.90 for total scale and r = 0.54–0.84 for subscales). The K-FCRI had significant correlations with the Korean version of Fear of Progression Questionnaire, European Organization for Research and Treatment of Cancer Quality of Life questionnaire Version 3.0, Hospital Anxiety and Depression Scale, and Fatigue Severity Score, supporting the good construct validity and psychometric properties of K-FCRI. The K-FCRI was confirmed as a valid and reliable psychometric test for measuring FCR of Korean survivors from cancers at various sites

Heritability of the morphology of optic nerve head and surrounding structures: The Healthy Twin Study.

Optic nerve head (ONH) and surrounding structures such as β-zone peripapillary atrophy (PPA) are important structures in glaucomatous pathogenesis. Thus, for understanding genetic components in glaucoma pathogenesis, it is necessary to evaluate the heritability of ONH and surrounding structures. The present study investigated the genetic influences on ONH and surrounding structures such as β-zone PPA and retinal vessels.A total of 1,205 adult twins and their family members (362 monozygotic (MZ) twin subjects (181 pairs), 64 dizygotic (DZ) twin subjects (32 pairs), and 779 singletons from 261 families), were part of the Korean Healthy Twin Study. ONH parameters including the vertical cup-to-disc ratio, the presence, the area and the location of β-zone PPA and the angular location of retinal vein were measured. The genetic influences on the structures were evaluated using variance-component methods.The intraclass correlation coefficient (ICC) values of axial length were highest among the parameters. The ICCs of the area and location of PPA were similar to those of vertical cup-to-disc ratio. However, retinal vessel angular locations showed low ICC values even in MZ twins. After age and sex adjustment, for axial length, vertical cup-to-disc ratio, the presence, area and location of PPA, the estimated narrow-sense heritability was 0.85, 0.48, 0.76, 0.50 and 0.65 in the right eye and 0.84, 0.47, 0.72, 0.46 and 0.72 in the left eye, respectively. The estimated narrow-sense heritability of angular location of the superior and inferior vein was 0.17 and 0.12 in the right eye and 0.13 and 0.05 in the left eye, respectively.ONH and surrounding structures such as vertical cup-to-disc ratio and the presence, the area and the location of β-zone PPA seemed to be determined by the substantial genetic influence, whereas the venous angular location did not

Additional file 1: Table S1. of Comparison of the association of mammographic density and clinical factors with ductal carcinoma in situ versus invasive ductal breast cancer in Korean women

Influence of the method of subjects recruitment on the association of the clinical, reproductive, and mammographic density characteristics with invasive ductal carcinoma and ductal carcinoma in situ. Table S2 Association of body mass index with breast cancer according to menopausal status. (DOCX 23 kb

Correlations between axial length (AL) and peripapillary atrophy (PPA)-to-disc ratio and angular location of retinal vein.

<p>(A), (B) Positively linear correlations were shown between AL and PPA-to-disc ratio. (C-F) Negatively linear correlations were shown between AL and angular locations of retinal vessels, but the correlations seemed weak.</p

Correlations of fundus parameters between family members.

<p>Correlations of fundus parameters between family members.</p

Intraobserver and interobserver reliability in fundus parameters.

<p>Intraobserver and interobserver reliability in fundus parameters.</p