This abstract was awarded the prize for best Nutrition Society Irish Section poster original communication.

A high proportion of Irish men and women have mean daily vitamin K intakes which are likely inadequate. For example, we had previously shown that 52 % of a nationally representative sample of the adult Irish population from 1997–1999⁽ Reference Duggan, Cashman and Flynn ^{1 )} had vitamin K₁ intakes below the UK recommended 1 µg/kg body weight^{( 2 )}, and 17 % and 27 % of men and women, respectively, met the current US adequate intakes for vitamin K.^{( 3 )} This may have consequences for vitamin K status and associated skeletal and non-skeletal health effects. This analysis explored associations between biochemical measures of vitamin K status and a biomarker of bone turnover and with a metabolic syndrome (MetS) risk score, and its component risk factors as defined by the International Diabetes Federation^{( 4 )}. Data [dietary, lifestyle and risk factor] and serum were accessed from the most recent nationally representative sample of Irish adults (National Adult Nutrition Survey 2008–2010) (www.iuna.net). Vitamin K status measures (undercarboxylated osteocalcin [GLU], carboxylated osteocalcin [GLA], and % osteocalcin undercarboxylated [%ucOC]) and carboxy-terminal collagen crosslinks (CTx; bone resorption marker) were measured in 692 adults by immunoassay.

^*Adjustment for age, sex, serum 25(OH)D, dietary calcium, smoking, HRT/oral contraception, PTH, BMI, total osteocalcin

^**Adjustment for age, sex, smoking and vitamin K intake. NS, non-significant association (P > 0·05)

Serum %ucOC was a significant (P < 0·0001) positive determinant of serum CTx, adjusting for confounders (model explained 48 % variability in serum CTx). Associations with MetS risk factors were driven by age. Surprisingly, in younger adults (<50y), serum %ucOC was significantly (P < 0·05) lower [Median (IQR)38·8 (27·5, 52·5) %] in those with central obesity and an additional MetS risk compared to those with no MetS risk[42·5 (30·4, 59·6) %], accounting for sex, smoking and vitamin K intake.

The pathogenesis for MetS and each of its components is complex and poorly understood. In addition to its role in skeletal health, vitamin K status may influence specific cardio-metabolic risk factors, however, further investigation is warranted to establish a causal relationship.