title: Plasma phylloquinone (vitamin K1) concentration and its relationship to intake in British adults aged 19-64 years.
abstract: Plasma phylloquinone (vitamin K1) concentration from non-fasted blood samples was examined by season, smoking status, socio-demographic factors and phylloquinone intake in a nationally representative sample of 1154 British individuals aged 19-64 years from the 2000-1 National Diet and Nutrition Survey. Geometric mean plasma phylloquinone concentration was 0.94 (95% CI 0.88, 1.00) nmol/l, with 95% of values in the range 0.10-8.72 nmol/l. Plasma phylloquinone concentrations of 530 men were significantly higher than those of 624 women (1.13 (95% CI 1.04, 1.22) v. 0.81 (95% CI 0.74, 0.88) nmol/l; P<0.001), independent of other factors. Women aged 19-34 years had significantly lower plasma phylloquinone concentration than their older counterparts. Women were also found to have lower plasma phylloquinone concentrations during summer compared with winter and spring (each P<0.01). In contrast, plasma phylloquinone concentration in men did not vary significantly by season or any of the socio-demographic or lifestyle factors. Plasma phylloquinone concentrations were positively correlated with phylloquinone intake in men and women (r 0.26 and 0.32 respectively; each P<0.001). Overall, forward stepwise multiple regression analysis revealed that 8% of the variation in plasma phylloquinone concentration was explained by phylloquinone intake, with a further 10% of its variation explained by plasma concentrations of gamma-tocopherol (6%) and retinyl palmitate (4%). After adjustment for age and corresponding nutrient intakes, plasma phylloquinone concentration was significantly associated (each P<0.01) with plasma concentrations of total and LDL-cholesterol, alpha- and gamma-tocopherols, retinyl palmitate, beta-carotene, lycopene and lutein plus zeaxanthin in men and women.
authors.affiliation: MRC Human Nutrition Research, Elsie Widdowson Laboratory, Fulbourn Road, Cambridge CB1 9NL, UK.
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Thane
authors.forename: Laura Y
authors.initials: LY
authors.lastname: Wang
authors.forename: W Andy
authors.initials: WA
authors.lastname: Coward
mesh_terms: D050154:Adiposity; D000328:Adult; D000367:Age Factors; D002784:Cholesterol / Q000097:blood; D004032:Diet; D004034:Diet Surveys; D005260:Female; D006801:Humans; D008019:Life Style; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D012621:Seasons; D012737:Sex Factors; D012907:Smoking; D012923:Social Class; D010837:Vitamin K 1 / Q000008:administration & dosage* / Q000097:blood*; D014815:Vitamins / Q000097:blood
chemical_list: D014815:Vitamins; D010837:Vitamin K 1; D002784:Cholesterol