Alarm at sunshine vitamin shortfalls

Friday September 6th, 2013

More than one third of the world’s population are deficient in vitamin D, the substance created by exposure to sunshine, a new systematic review has revealed.

Dr Kristina Hoffmann of the Mannheim Institute of Public Health, Heidelberg University, Germany, examined almost 200 population-based vitamin D studies from 44 countries across the globe and found that people in North America have the highest vitamin D values.

But just over 37% of those studied were found to be deficient in vitamin D. Using 25(OH)D blood test to measure the values, they found mean serum values were below 50 nmol/l, which is considered inadequate by health authorities worldwide.

Low levels of vitamin D can have a potentially serious impact on health, particularly on bone and muscle health.

It can cause rickets in children, while adults are at risk of osteomalacia, osteopenia, osteoporosis and fracture. There is also growing evidence that points to low vitamin D levels being associated with cancer and heart disease risks.

Despite this growing body of evidence and its importance to public health, data about vitamin D status at the population level are limited and studies are hampered by lack of consensus and consistency, writes Dr Hoffmann in the British Journal of Nutrition.

This review is the first to focus on patterns of vitamin D levels worldwide and in key population subgroups, using continuous values for 25(OH)D as a way of improving comparisons.

The lack of similarity between the studies within each region meant it was difficult to draw conclusions on overall vitamin D levels per population, said Dr Hoffmann.

There is also a need for research designs that minimise potential sources of bias, which will then help to reinforce understanding of vitamin D status.

Judy Stenmark, of the International Osteoporosis Foundation (IOF), said vitamin D deficiency had to be addressed as a matter of urgency.

“Given the global increase in the number of seniors and the almost fourfold increase in hip fractures due to osteoporosis since 1990, public health officials must address the impact of inadequate vitamin D status on fracture risk and overall health in their ageing populations as well as on children and adolescents,” she said.

Hilger J, Friedel A et al. A systematic review of vitamin D status in populations worldwide. Br J Nutr 4 September 2013; doi: 10.1017/s0007114513001840.

Tags: Europe | General Health | North America

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