The Association of Vitamin D Binding Protein Gene Polymorphism and Adult Height

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 257-280-Disorders of Vitamin D Metabolism & Action
Basic/Translational
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-274
Hataikarn Nimitphong*1, Piyamitr Sritara1, La-or Chailurkit1, Suwannee Chanprasertyothin1, Sukit Yamwong1, Wipa Ratanachaiwong2 and Boonsong Ongphiphadhanakul1
1Ramathibodi Hospital, Bangkok, Thailand, 2Medical and Health Office, Electricity Generating Authority of Thailand, Nonthaburi, Thailand
Background:Vitamin D binding protein (DBP) is the major carrier protein of circulating vitamin D and its metabolites. Besides its role in vitamin D transport, DBP possesses a number of biological functions including fatty acid transport and macrophage activation. To date, DBP polymorphism has been associated with a number of disorders such as osteoporosis, autoimmune thyroid disease and multiple sclerosis. It is unknown at present if DBP plays any role in bone growth. In the present study, we investigated the association between DBP gene polymorphism and adult height in Thais.

Materials and Methods:Subjects consisted of 2,042 individual aged 25-54 years. The study population was a cross-sectional cohort of employees of the Electricity Generating Authority of Thailand (EGAT). The study was approved by the Committee on Human Rights Related to Research Involving Human Subjects, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, prior to the commencement of the study. All subjects gave written informed consent. Genomic DNA was isolated from peripheral blood leukocytes using phenol-chloroform method. The DBP rs2282679 polymorphism was genotyped using a TaqMan assay with allele-specific probes on an ABI Prism 7500 real-time PCR system (Applied Biosystems, Foster City, CA).Serum 25-hydroxyvitamin D [25(OH)D] was measure by liquid chromatography/tandem mass spectrometry. Vitamin D deficiency was defined as the 25(OH)D concentration of less than 20 ng/mL. Data was expressed as mean±SD.

Results: There were 2,042 subjects with the mean age of 40.4±6.9 years (74% of subjects were male) and mean BMI of 24.2±3.7kg/m2 in this study. The mean 25(OH)D levels were 24.9±6.2 ng/mL. Twenty-one percent of subjects had vitamin D deficiency (49% of subjects were male). The genotype distribution of the DBP rs2282679 polymorphism was 129 CC, 733 CA and 1,180 AA which conformed to Hardy-Weinberg equilibrium. Total 25(OH)D levels increased progressively with the number of the A (major) allele. 25(OH)D levels according to genotype were 21.2±4.2, 23.8±5.8 and 26±6.3 ng/mL for the CC, CA and AA genotype, respectively (p<0.001). Body height, however, was significantly lower in subjects having the A allele (CA or AA, n=1,913) as compared to those without the A allele (CC, n=129) (166.2±7.6 vs. 167.9±7.8 cm, p= 0.019). Other factors associated with body height included gender (male = 169.2±6 cm and female = 157.9±5.4 cm, p<0.001), age (r=-0.158, p<0.001) and circulating 25(OH)D (r=0.171, p<0.001). In a multiple linear regression analysis, it was found that the absence of DBP A allele was associated with taller body status (β=0.045, p< 0.01) independent of age and gender. No effect of total 25(OH)D was found after controlling for the DBP polymorphism, age and gender (p = 0.44).

Conclusion: Vitamin D binding protein gene polymorphism rs2282679 is associated with adult height independent of vitamin D status.

Nothing to Disclose: HN, PS, LOC, SC, SY, WR, BO

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