Ethnic differences in osteocalcin γ-carboxylation, plasma phylloquinone (vitamin K1) and apolipoprotein E genotype

• Published in: European journal of clinical nutrition Vol. 59; no. 1; pp. 72 - 81
• Main Authors: Beavan, S.R, Prentice, A, Stirling, D.M, Dibba, B, Yan, L, Harrington, D.J, Shearer, M.J
• Format: Journal Article
• Language: English
• Published: Basingstoke Nature Publishing 2005; Nature Publishing Group
• Subjects: Adult; Aged; Antifibrinolytic Agents - blood; apolipoproteins; Apolipoproteins E - genetics; Biological and medical sciences; Blood; blood serum; carboxylation; China - ethnology; Clinical nutrition; Comparative analysis; Cross-Sectional Studies; Diseases of the osteoarticular system; England - ethnology; Epidemiology; Ethnicity; Female; Gambia - ethnology; Genotype; Humans; Medical sciences; menopause; Middle Aged; Minority & ethnic groups; nationalities and ethnic groups; nutritional status; osteocalcin; Osteocalcin - blood; Osteocalcin - metabolism; osteoporosis; Osteoporosis, Postmenopausal - epidemiology; Osteoporosis, Postmenopausal - ethnology; Osteoporosis, Postmenopausal - metabolism; Osteoporosis. Osteomalacia. Paget disease; phylloquinone; Plasma; Postmenopause - ethnology; Postmenopause - metabolism; Premenopause - ethnology; Premenopause - metabolism; Proteins; Risk Factors; Vitamin K 1 - administration & dosage; Vitamin K 1 - blood; Vitamins; Women; China; England; Gambia; Human; Osteocalcin; apoE genotype; ethnic; Nutrition; Diseases of the osteoarticular system; Genotype; E-Vitamins; γ-carboxylation; Ethnic group; Blood plasma; Osteoporosis; Apolipoprotein E; Carboxylation; Female; Phylloquinone; Public health; Comparative study; Vitamin K
• ISSN: 0954-3007; 1476-5640
• DOI: 10.1038/sj.ejcn.1602037

Objective: To investigate plasma osteocalcin gamma-carboxylation and its relationship to plasma phylloquinone concentration and apolipoprotein E (apoE) genotype in women from three ethnic groups with differing osteoporotic fracture risk. Design and subjects: Fasted blood samples were collected from postmenopausal Gambian (n=50), British (n=31) and Chinese women (n=23), and 11 premenopausal women in each group from three cross-sectional studies. Results: After adjustment for total osteocalcin, plasma undercarboxylated osteocalcin (adjusted ucOC) was lowest in Chinese and highest in British women postmenopause (British vs Chinese 103% higher, P<0.0001; Gambian vs Chinese 66% higher, P<0.01). No differences were observed premenopause. Within each ethnic group, adjusted ucOC was similar pre- and postmenopause. Postmenopause, plasma phylloquinone was higher in Chinese women (1.0 ng/ml) than in British (0.31 ng/ml) and Gambian women (0.36 ng/ml) (P<0.0001). Premenopause, plasma phylloquinone was higher in Gambian and Chinese women (0.6 ng/ml) than in British women (0.3 ng/ml; P=0.01). Plasma phylloquinone and adjusted ucOC were inversely related in postmenopausal British women (R2=32.4%; P=0.0008). ApoE4 frequency was Gambian 32.6%, British 13.8% and Chinese 6%. A lower adjusted ucOC was associated with apoE2 genotype in British and Chinese women. Ethnic differences in adjusted ucOC persisted after adjustment for phylloquinone and apoE genotype. Conclusion: These preliminary data indicate suboptimal vitamin K status in postmenopausal British compared to Chinese and Gambian women. Ethnic differences in apoE genotype may also influence osteocalcin gamma-carboxylation status. The study highlights the need for larger epidemiological investigations of ethnic differences in vitamin K status and the possible implications to bone health.