Vitamin D status and nutrition in Europe and Asia

Abstract

Vitamin D status is highly different in various countries of Europe, the Middle East and Asia. For this review, vitamin D deficiency is defined as serum 25-hydroxyvitamin D (25(OH)D) <25 nmol/l. Within European countries, serum 25(OH)D is <25 nmol/l in 2-30% of adults, increasing in the elderly and institutionalized to more than 80% in some studies. A north-south gradient was observed for serum 25(OH)D in the Euronut and MORE studies with higher levels in Scandinavia and lower levels in Italy and Spain and some Eastern European countries. This points to other determinants than sunshine, e.g. nutrition, food fortification and supplement use. Mean vitamin D intake in Scandinavia is 200-400IU/d, twice that in other European countries. Very low serum 25(OH)D levels have been reported in the Middle East, e.g. Turkey, Lebanon, Jordan and Iran. In these countries serum 25(OH)D was lower in women than in men and associated with clothing habits. In a Lebanese survey, vitamin D deficiency was observed in the majority and occurred mainly in veiled women. In India, vitamin D deficiency was observed in more than 30%, vitamin D status being poor in school children, pregnant women and large cities. Vitamin D status was much better in Malaysia and Singapore, but lower serum 25(OH)D was observed in Japan and China. Rickets and osteomalacia appear quite common in India, but precise data are lacking. Immigrants in Europe from the Middle East and Asia carry a high risk for vitamin D deficiency, pregnant women being especially at risk. Comparison of vitamin D status between countries is hampered by interlaboratory variation of serum 25(OH)D measurement. In addition, there is a need of population-based data. In conclusion, vitamin D deficiency is common in Southern Europe, the Middle East, India, China and Japan. It is less common in Northern Europe and Southeast Asia. Risk groups are young children, the elderly, pregnant women and non-western immigrants in Europe. Important determinants are skin type, sex, clothing, nutrition, food fortification, supplement use, BMI and degree of urbanization.