Effect of apolipoprotein E genotype on vitamin K status in healthy older adults from China and the UK.

The vitamin K concentration in the circulation and the availability of vitamin K to bone may be affected by factors influencing lipoprotein metabolism, such as apoE genotype. The relationships between markers of vitamin K status, bone mineral content and apoE genotype were studied in healthy older men and women aged 60-83 years, 177 from Shenyang, China, and 132 from Cambridge, UK. Fasting plasma was analysed for vitamin K1, triacylglycerol, total osteocalcin, undercarboxylated osteocalcin (ucOC) and apoE genotype. Hip bone mineral content was measured using dual-energy X-ray absorptiometry. Subjects were grouped according to apoE genotype as E2/3, E3/3 and [E3/4+E4/4]. The mean plasma vitamin K1 concentration of the three genotype groups was significantly higher and the percentage ucOC was lower in the Chinese than in the British subjects (P<0.01). A higher vitamin K1 concentration was found in subjects with [E3/4+E4/4] than those with either E2/3 or E3/3 in Cambridge (32.2 (SE 14.6 ) %, P=0.03; 24.6 (SE 10.7 ) %, P=0.02). Similar trends were observed although were not statistically significant in Shenyang (26.5 (18.9) %, P=0.16; 23.1 (13.0) %, P=0.08). Subjects with [E3/4+E4/4] had a lower percentage ucOC (total osteocalcin adjusted) than did those with either E2/3 or E3/3 in Shenyang (65.1 (27.2) %, P=0.02; 49.6 (19.9) %, P=0.01 respectively) but not in Cambridge. This study demonstrates that a superior vitamin K status is associated with the apoE4 genotype in healthy older individuals from China and the UK.