Vitamin D insufficiency is a global issue

In a report published on June 19, 2009 in the journal Osteoporosis International, the International Osteoporosis Foundation's expert working group on nutrition revealed the global extent of vitamin D insufficiency. They found that suboptimal vitamin D levels are common in most areas of the world, and appear to be on the rise.

The committee, chaired by Ambrish Mithal of Indraprastha Apollo Hospitals in New Delhi, India, reviewed published literature concerning the vitamin D levels of people residing in Asia, Europe, Latin America, the Middle East and Africa, North America and Oceania. Although there was some of variance in assay methodology and in the definition of vitamin D deficiency and insufficiency, 25-hydroxyvitamin levels below 75 nanomoles per liter, which are generally considered insufficient, were found to be widespread in every region studied. Older age, female gender, higher latitude, winter season, dark skin pigmentation, decreased sun exposure, dietary habits, and a lack of vitamin D fortification were identified as factors contributing to low vitamin D levels. Levels below 25 nanomoles per liter, indicating deficiency, were prevalent in South Asia and the Middle East, where increased urbanization and the wearing of clothing that covers most of the skin are major contributors.

Adequate vitamin D levels are critical to maintain optimal calcium levels in the body, and are essential for normal bone mineralization and growth. Inadequate vitamin D increases the risk of osteoporosis and hip fracture in older individuals, and rickets in children, which can cause deformity and fractures.

"Reports from across the world indicate that hypovitaminosis D is widespread and is re-emerging as a major health problem globally," the authors conclude. The findings indicate that preventive measures, including the encouragement of limited sun exposure, improved dietary intake and food fortification, must be initiated at the national level.