Today the International Osteoporosis Foundation (IOF) has launched a new interactive map which provides a graphical illustration of vitamin D (25OHD) levels around the world. The map, which includes accompanying tables with data from each country, is available at
IOF CEO Judy Stenmark, stated, “IOF has developed the map in order to meet several needs. Aside from being a useful tool for researchers, this map will help health care professionals and health authorities understand the scale of suboptimal levels of vitamin D worldwide. The map has also revealed the urgent need for more research as incredibly large gaps in data exist, both in terms of countries and population groups.”
A systematic review of worldwide published data from 1990 to 2011 identified 200 studies from 46 countries, mostly coming from Europe. The map color codes levels of vitamin D status, with green indicating an optimal vitamin D status (75+nmol/l) and yellow indicating sub-optimal status (50-75 nmol/l). Orange highlights vitamin D blood levels between 25-50 nmol/l which are considered insufficient, and red indicates vitamin D deficiency (below 25nmol/l).
Key findings include:
- In children, gaps in data were identified in large parts of Africa, Central and South America, Europe and most of the Asia-Pacific region.
- In adults, there was lack of information in Central America, much of South America and Africa.
- Vitamin D insufficiencies affect both the developing world and industrialized countries
- Low levels of vitamin D are more often found amongst women than men
- Eighty-eight (88.1%) per cent of the included populations had mean 25(OH)D values below 75 nmol/l, 37.3% below 50 nmol/l and 6.7% below 25 nmol/l, respectively.
- Overall, more than one third of the population identified in the worldwide study had insufficient levels below 50nmol/l and 6.7% were vitamin D deficient (below 25nmol/l)
- Only a minority (approximately 10%) of the populations included in the map had optimal levels of vitamin D (above 75nmol/l).
Vitamin D levels are a concern worldwide because insufficient intake has been shown to have serious health implications. In the elderly, low levels of vitamin D are linked to decreased muscle strength and increased risk of falls and fractures. In children, severe vitamin D deficiency can lead to bone deformities known as rickets. As well, there is evidence that children born to mothers who are vitamin D deficient during pregnancy may have reduced bone mass, which could be a risk factor for osteoporosis later in life. Although further research is needed, observational studies also suggest that vitamin D may play a role in other non-musculoskeletal disorders.
Vitamin D is primarily made in the skin when it is exposed to sunlight, with only limited amounts obtainable from food sources. Whether an individual has adequate vitamin D is dependent on a multitude of factors, including age, gender, skin pigmentation, sunlight exposure, geographical latitude, the use of sunscreen, dietary habits and supplement intake. The map shows that the degree of vitamin D insufficiency varies widely and affects all parts of the world– both at northern latitudes, where winters are long and dark, as well as at sunny southern latitudes, where people may avoid direct sun exposure.
Professor Bess Dawson-Hughes, general secretary of IOF and member of the IOF Nutrition Working Group stated, “The map identifies vitamin D insufficiency in many regions and different population groups. Given the growing numbers of seniors in both the developed and developing world, the issue of suboptimal vitamin D levels takes on a critical health economic significance. We must spread the urgent message that the implementation of low-cost and effective strategies to ensure optimal levels of vitamin D, particularly in high risk groups and seniors, can make a dramatic difference to health and quality of life, as well as potentially reduce a significant disease burden on healthcare systems worldwide.”
About the IOF Vitamin D Map
The map, which will be updated annually, is available on https://www.iofbonehealth.org/facts-and-statistics/vitamin-d-studies-map. It will provide researchers, medical practitioners and policymakers with an invaluable resource in the fight against vitamin D deficiency.
The map was developed in association with DSM.
The research protocol and data is outlined in the paper ‘A global representation of vitamin D status in healthy populations’, published in the online journal Archives of Osteoporosis at http://www.springerlink.com/content/0j47t1552v068j71/?MUD=MP
IOF individual members (free registration here) have free access to Archives of Osteoporosis.