Premium
Exploration of the determinants of seasonal Vitamin D
Author(s) -
Kimlin Michael G.
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.996.13
Subject(s) - percentile , vitamin d and neurology , medicine , vitamin , seasonality , demography , epidemiology , ambulatory , environmental health , biology , mathematics , statistics , ecology , sociology
A fundamental assumption when undertaking studies into Vitamin D and populations is that the relative “ranking” of an individual remains constant with respect to time. That is, an individual with the lowest percentile of Vitamin D status in summer will also have the lowest percentile)= of Vitamin D in summer, even though the Vitamin D status may have increased from summer to winter. This work investigates if such relative ranking exists in populations. Most individual‐level epidemiological studies examining vitamin D status in relation to disease risk measure serum 25(OH)D levels at a single time point, statistically “adjusting” for seasonal effects based on the mean seasonal variation in 25(OH)D levels. In longitudinal studies, more than one pre‐existing blood sample may be used, but in comparing either intra‐individually or inter‐individually, adjustment for season is still usually required. The 25(OH)D levels of 60 healthy ambulatory adults (42 female) aged 18 to 87 (median 49) years, in southeast Queensland, Australia (27°S) were tracked from winter to summer. After informed consent, participants were administered a questionnaire surveying past (previous 30 days) sun exposure, timing of sun exposure, sun protection used and dietary Vitamin D intakes. From this collected data, exploration of the determinants of seasonal Vitamin D status was undertaken.