Vitamin D Reference Values for a Global Medical System

Laboratory and Field Study

Vitamin D - also known as the sunshine vitamin - plays an important role in regulating the calcium level in blood and bone metabolism. Most vertebrates, including humans, synthesize vitamin D in their bodies when the skin is exposed to ultra violet b-rays (UV-B). Only small amounts are associated and covered by dietary intake. Hence, sun exposure plays an important role in vitamin D levels, which depends on cultural and religious traditions (e.g., clothing, sunscreen use), and complexion. Many studies have examined how certain factors affect the levels of vitamin D in the blood. However, only a few of these studies have specifically looked at Arab and Mediterranean societies in relation to vitamin D levels. One factor that can impact vitamin D levels in these societies is a dress code where the skin is barely exposed to sunlight. Since sunlight is a key source of vitamin D synthesis in the body, this reduced exposure can lead to lower levels of vitamin D in the blood

Establishing vitamin D standard values for Palestine and neighboring countries

It has been observed that many residents in Palestine are supposedly suffering from vitamin D deficiency and given vitamin D supplements as part of their treatment for diverse health problems. So far, vitamin D reference values have been established focusing on Western societies and do not necessarily suit the Palestinian population. These studies already revealed the need for different standard values in different societies and populations because a single reference value is not sufficient in a global medical system. Hence, the establishment of a vitamin D standard value for Palestine will be valuable and a great benefit for neighboring countries such as Jordan, Lebanon, or Syria, too. Furthermore, these standards require a deep understanding of the controlling parameters and factors on these values.

Investigating the controlling factors on vitamin D levels

In this tandem project, AGYA members Prof. Dr. Ahmad Amro and Dr. Ahmed Hegazy aimed to establish reference values for vitamin D levels for residents in Palestine, taking into account genetic and cultural factors that influence vitamin D metabolism and were compared with reference ranges in Europe (Germany, France, U.K.). In order to prevent misinterpretation of vitamin D deficiencies in these societies, the AGYA members collected and analyzed the vitamin D levels from blood samples of 300 healthy Palestinian residents from the West Bank. Simultaneously, the participants took part in a survey focusing on the demographic and socioeconomic background, cultural behavior and traditions, and the medical condition and diet of each participant. Whereas the questionnaire was conducted and analyzed by the team of Ahmad Amro at Al-Quds University, the comparing study of vitamin D levels in Palestine, Germany, France, and U.K. had been done by Ahmed Hegazy in the laboratories at the Charité – Universitätsmedizin Berlin. A commonly referenced optimal range for serum vitamin D levels in Western European societies is typically considered to be between 20-30 ng/ml. However, this study revealed that a serum level close to 14 ng/ml of vitamin D as an optimal value, at least for the general population of the West Bank. Fluctuations of this value should be considered according to individual health status including skeletal and non-skeletal conditions, solar radiation exposure, and dietary intake.