Vitamin D deficiency in Tasmania: A whole of life perspective.
Intern Med J. 2012 Apr 5. doi: 10.1111/j.1445-5994.2012.02788.x
van der Mei IA, Dore D, Winzenberg T, Blizzard L, Jones G.
Qualifications: PhD Position: Senior Research Fellow Institution or Affiliation: Menzies Research Institute Address: 17 Liverpool St, Hobart, TAS 7000 Email: Ingrid.vanderMei at utas.edu.au
Qualifications: BBiotech(Hons) Position: PhD student Institution or Affiliation: Menzies Research Institute Address: 17 Liverpool St, Hobart, TAS 7000 Email: Dawn.Dore at utas.edu.au
Qualifications: MD Position: Senior Research Fellow Institution or Affiliation: Menzies Research Institute Address: 17 Liverpool St, Hobart, TAS 7000 Email: Tania.Winzenberg at utas.edu.au
Qualifications: PhD Position: Senior Biostatistician Institution or Affiliation: Menzies Research Institute Address: 17 Liverpool St, Hobart, TAS 7000 Email: Leigh.Blizzard at utas.edu.au
Qualifications: MD Position: Professor Institution or Affiliation: Menzies Research Institute Address: 17 Liverpool St, Hobart, TAS 7000 Email: G.Jones at utas.edu.au.
Objective:? This study aims to describe the life-time picture of vitamin D deficiency, as measured by serum 25(OH)D concentration, in Tasmania (latitude 43°S).
Methods:? Five cross-sectional studies were used: A sample of primary school children (n=201, aged 7-8 years), two samples of adolescents (sample 1: n=374, aged 15-18 years; sample 2: n=136, aged 16-19 years), a sample of young to middle aged adults (n=262, aged 19-59 years), and a sample of older adults (n=1092, aged 50-80 years).
Results:? In winter/spring, approximately two third of the adolescents and adults (young, middle-aged and older) had 25(OH)D levels ?50 nmol/L and around 10% had 25(OH)D levels ?25 nmol/L. The prevalence of vitamin D deficiency was much lower for primary school children (11.5% <50 nmol/L, 0.5% ?25 nmol/L). In summer/autumn, approximately one third of the adolescents and adults had 25(OH)D levels ?50 nmol/L, and very few had 25(OH)D levels ?25 nmol/L. For the adolescents and adults, even among those who reported the highest category of sun exposure, approximately 45% had 25(OH)D levels ?50 nmol/L in winter/spring.
Conclusions:? Vitamin D deficiency was uncommon among our sample of primary school children, but increased substantially during the teenage years, and seemed to remain high throughout the rest of life suggesting mild vitamin D deficiency is endemic in Tasmania apart from in the very young.
© 2012 Menzies Research Institute, University of Tasmania. Internal Medicine Journal © 2012 Royal Australasian College of Physicians.
PMID: 22487197
Vitamin D decreases with how old the child is in school
In the US (and perhaps Tasmania) children the first years of school get many recess hours outdoors - thus getting lots of vitamin D
As the child gets older the # of outdoor hours decrease, so less vitamin D