A new large (n=10.735), cross-sectional study has revealed that despite some of the highest sunlight levels on the globe, 62.65% of females and 40.6% of males in the Kingdom of Saudi Arabia (KSA) are deficient in vitamin D.
The Kingdom of Saudi Arabia (KSA) is a country which has one of the highest number of sunny days on the globe, but despite this, a new cross-sectional study (1) has revealed rampant vitamin D deficiency. Whilst tradition in KSA calls for most of the skin to be covered, it is most likely that the modern trend to spend most of their lives inside is the main culprit. Of the 10,735 participants who took part in the study during the spring/summer of 2013 (all aged 15 years or above), 62.65% of females and 40.6% of males were deficient in vitamin D, i.e., having plasma levels less than 28 ng/mL as defined by the Saudi Ministry of Health.
Humans traditionally obtain much of their vitamin D requirement from exposure of their skin to the sun. Even a relatively short exposure time (15 to 30 minutes) in strong sun can often provide the daily requirement. However, factors such as the degree of skin pigmentation and genetics will cause large variations. Vitamin D deficiency has alarming consequences for bone health and the risk of some autoimmune diseases. However, until recently, the inhabitants of sun-drenched countries such as KSA were not thought to be at risk. Though some recent small studies did appear to indicate a problem of deficiency in a substantial proportion of the population (2). The new study by Tuffaha et al. (1) sought for the first time to evaluate the risk across the population of KSA. They found that females and the obese were most likely to have insufficient levels of vitamin D. Only a few percent of the participants took vitamin D supplements, and these were largely drawn from the educational elite.
Whilst the Saudi authorities define insufficiency as a vitamin D blood plasma level of 28 ng/mL or below, globally there is a considerable lack of consensus on the necessary level. Indeed a recent paper by Alshahrani et al. (3) suggests that insufficiency begins at levels of 32 ng/mL or less.
Unfortunately, processed foods manufactured in KSA are not routinely fortified with vitamin D (4). As the KSA population is only likely to spend more time indoors in the future, it seems prudent for the authorities to advise the population on the risk of vitamin D deficiency and recommend the use of daily supplements to “at risk” groups, such as females over the age of 50 years.