Bone Abstracts

Background: The traditional Inuit diet in Greenland consists mainly of fish and marine mammals. The marine diet is an important source for vitamin D in Greenland. Vitamin D has anti-inflammatory capacity but markers of inflammation were high in Inuit with a high intake of marine food items. Yet, the effect of vitamin D on inflammation in Inuit remains unsettled.

Objectives: To investigate the association between vitamin D and markers of inflammation in a population with a high intake of marine food items.

Methods: 535 Inuit and non-Inuit living in West- and East Greenland participated in the survey. Interview-based food-frequency questionnaires were used to obtain information concerning dietary habits. Blood samples were drawn for analysis of 25-hydroxy-vitamin D and the inflammatory markers hsCRP and YKL-40.

Results: Participants were divided into three groups based on degree of intake of traditional Inuit diet. Markedly more Inuit than non-Inuit had a frequent intake of the traditional marine Greenlandic diet (79%), while the reverse was seen for non-Inuit, where 83% lived mainly on imported food items (P<0.001). The diet groups (Inuit diet/mixed diet/imported foods) associated with vitamin D levels in serum, 74.2/69.8/52.9 nM (P<0.001), hsCRP 1.6/1.4/1.3 mg/l (P=0.002) and YKL-40 130/95/61 ng/ml (P<0.001), respectively. A decreasing YKL-40 level was found with rising vitamin D level in Inuit (Inuit diet P=0.002; mixed diet P=0.011). YKL-40 level decreased with rising vitamin D level after adjusting for other factors known to influence inflammation (P<0.001). However, this was not seen for hsCRP.

Conclusion: Vitamin D and markers of inflammation vary in parallel with the intake of the marine Inuit diet. Vitamin D levels were inversely associated with YKL-40 levels, but not with hsCRP. The hypothesised anti-inflammatory effect of vitamin D was not supported for the hsCRP; hence other factors in the marine diet may be speculated to influence inflammation.