Submitted to: Archives of Osteoporosis
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/6/2012
Publication Date: 12/12/2012
Citation: Wahl, D.A., Cooper, C., Ebeling, P.R., Eggersdorfer, M., Hilger, J., Hoffman, K., Josse, R., Kanis, J.A., Mithal, A., Pierroz, D.D., Stenmark, J., Stocklin, E., Dawson-Hughes, B. 2012. A global representation of vitamin D status in healthy populations. Archives of Osteoporosis. 7:155-172. Interpretive Summary: Vitamin D plays an important role in the development of bone and its preservation throughout life and may also reduce the burden of infections and many common chronic diseases. The International Osteoporosis Foundation (IOF) took the initiative to describe the vitamin D status in the general population in different countries based on a systematic review. The aims of the study were to provide a general overview of vitamin D status in countries for which data were available, examine the existing heterogeneities in vitamin D status, and identify research gaps. A systematic search performed by the Mannheim Institute revealed 2556 articles. Each was reviewed and 200 articles met study inclusion criteria for this analysis. Blood levels of vitamin D (25OHD) levels were divided into four categories: >74 nmol/L, 50-74, 25-50, and <25. Two age groups were considered: 1-18 yrs and 19 years and older. This investigation revealed that for children, very few data exist outside of the US, Canada, and the Pacific Rim countries and among those with available data, 25OHD levels were generally in the range of 25-50 nmol/L. Among adults, most regions offer some data and their 25OHD ranges are approximately evenly split between 25 to 49 and 50 to 74 nmol/L. This analysis provides a snap shot or summary of 25OHD levels around the globe and reveals large areas where data are absent and large areas in which 25OHD levels fall well below those currently recommended for bone health. This analysis may increase awareness of the scope of vitamin D insufficiency worldwide and prompt action to correct it.
Technical Abstract: This paper provides an overview of vitamin D status in countries for which data were available, examines the existing heterogeneities in vitamin D status and identifies research gaps. A graphical illustration of global vitamin D status was developed based on a systematic review of the world wide literature published between 1990 and 2011. Studies were eligible if they included samples of randomly selected males and females from the general population and assessed circulating 25-hydroxyvitamin D (25OHD) levels. Two different age categories were selected: children and adolescents (1-18 years) and adults (>18 years). Studies were chosen to represent a country based on a hierarchical set of criteria. In total, 200 studies from 46 countries met the inclusion criteria, most coming from Europe. Forty-two of these studies (21%) were classified as representative. 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. Large regions were identified for which mean 25OHD levels were below 50 nmol/L. This study provides an overview of 25OHD levels around the globe. It reveals large gaps in information in children and adolescents and smaller but important gaps in adults. In view of the importance of vitamin D to musculoskeletal growth, development, and preservation, and of its potential importance in other tissues, we strongly encourage new research to clearly define 25OHD status around the world.