Decrease in vitamin D status in the Greenlandic adult population from 1987-2010.

BACKGROUND:Low vitamin D status may be pronounced in Arctic populations due to limited sun exposure and decreasing intake of traditional food. OBJECTIVE:To investigate serum 25(OH)D3 as a measure of vitamin D status among adult Inuit in Greenland, predictors of low serum 25(OH)D3 concentrations and the trend from 1987 to 2005-2010. DESIGN:A total of 2877 randomly selected Inuit (≥ 18 years) from the Inuit Health in Transition study were included. A sub-sample (n = 330) donated a blood sample in 1987 which allowed assessment of time trends in vitamin D status. RESULTS:The geometric mean serum 25(OH)D3 (25[OH]D2 concentrations were negligible and not reported) in 2005-2010 was lowest among the 18-29 year old individuals (30.7 nmol/L; 95% CI: 29.7; 31.7) and increased with age. In all age-groups it decreased from 1987 to 2005-2010 (32%-58%). Low 25(OH)D3 concentrations (<50 nmol/L) were present in 77% of the 18-29 year old and decreased with age. A characteristic seasonal variation in 25(OH)D3 concentrations was observed (range 33.2-57.1 nmol/L, p