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Vitamin D Levels and Productivity in Middle-Eastern Countries To the Editor:
W
e read with interest Plotnikoff and colleagues’1 article on vitamin D deficiency and productivity. Obviously, there are many factors that can lead to reduced productivity, and lack of vitamin D may be one contributory factor. If it is a significant causal factor, then the implications for workers in many countries, including those in the Middle East, are considerable. With the abundance of sunshine in the Middle East, it might be assumed that vitamin D deficiency among workers in the desert environment is unlikely. However, there have been several studies2,3 indicating low vitamin D levels especially in women from Arab and other Middle-Eastern countries. We have recently determined 25hydroxyvitamin D levels in a random sample of adolescents (aged between 15 and 18 years) in Al-Ain city in the United Arab Emirates. Thirteen percent of the apparently healthy adolescents had 25-hydroxyvitamin D levels less than 15 ng/mL. There was a substantially higher proportion of female
adolescents (20%) with vitamin D deficiency than their male counterparts (5% with deficiency). Several factors may contribute to this finding, including a lack of outdoor activity, a diet deficient in milk and other foods containing vitamin D,4 and female use of garments that cover the whole body except for the face and hands. Adolescent girls who adhere to this conservative dress code in Israel,5 Jordan,6 and Turkey7 have also been reported to have vitamin D deficiency. The effect of low vitamin D levels on productivity could have an important impact on the pace of economic development in rapidly developing countries such as those in the Middle East. If productivity and performance of school children are also affected, there may be public health and occupational health consequences for future generations. With the changing sociocultural environment in these countries, we have yet to see a progressive improvement in vitamin D levels with widening of dietary choices, more women in the workplace, and an increased interest in outdoor activity. The time trends with regard to vitamin D levels in MiddleEastern populations, and an accompanying assessment of productivity levels, may lend further support to the findings of Plotnikoff et al.1 Tar-Ching Aw, MB, PhD Syed M. Shah, MD, PhD, MPH Faculty of Medicine & Health Sciences
Institute of Public Health UAE University, Al-Ain United Arab Emirates
REFERENCES 1. Plotnikoff GA, Finch MD, Dusek JA. Impact of vitamin D deficiency on the productivity of a health care workforce. J Occup Environ Med. 2012;54:117–121. 2. Saadi HF, Dawodu A, Afridi BO, Zayed R, Benedict S, Nagelkerke N. Efficacy of daily and monthly high-dose calciferol in vitamin D deficient nulliparous and lactating women. Am J Clin Nutr. 2007;85:1565–1571. 3. Gannage-Yared MH, Chemali R, Yaacoub N, Halaby G. Hypovitaminosis D in a sunny country: relation to lifestyle and bone markers. J Bone Miner Res. 2002;15:1856–1862. 4. Laleye LC, Kerkadi AH, Wasesa AA, Rao MV, Aboubacar A. Assessment of vitamin D and vitamin A intake by female students at the United Arab Emirates University based on self-reported dietary and selected fortified food consumption. Int J Food Sci Nutr. 2011;62:370–376. 5. Tsur A, Metzger M, Dresner-Pollak R. Effect of different dress style on vitamin D level in healthy young Orthodox and ultra-Orthodox students in Israel. Osteoporos Int. 2011;11:2895–2898. 6. Mallah EM, Hamad MF, El Manaseer MA, et al. Plasma concentrations of 25-hydroxyvitamin D among Jordanians: effect of biological and habitual factors on vitamin D status. BMC Clin Pathol. 2011;11:8. 7. Hatun S, Islam O, Cizmecioglu F, et al. Subclinical vitamin D deficiency is increased in adolescent girls who wear concealing clothing. J Nutr. 2005;135:218–222.
C 2014 by American College of OccupaCopyright tional and Environmental Medicine DOI: 10.1097/JOM.0b013e31825cb6ce
JOEM r Volume 56, Number 4, April 2014 Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
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Vitamin D Levels and Productivity in Middle-Eastern Countries To the Editor:
W
e read with interest Plotnikoff and colleagues’1 article on vitamin D deficiency and productivity. Obviously, there are many factors that can lead to reduced productivity, and lack of vitamin D may be one contributory factor. If it is a significant causal factor, then the implications for workers in many countries, including those in the Middle East, are considerable. With the abundance of sunshine in the Middle East, it might be assumed that vitamin D deficiency among workers in the desert environment is unlikely. However, there have been several studies2,3 indicating low vitamin D levels especially in women from Arab and other Middle-Eastern countries. We have recently determined 25hydroxyvitamin D levels in a random sample of adolescents (aged between 15 and 18 years) in Al-Ain city in the United Arab Emirates. Thirteen percent of the apparently healthy adolescents had 25-hydroxyvitamin D levels less than 15 ng/mL. There was a substantially higher proportion of female
adolescents (20%) with vitamin D deficiency than their male counterparts (5% with deficiency). Several factors may contribute to this finding, including a lack of outdoor activity, a diet deficient in milk and other foods containing vitamin D,4 and female use of garments that cover the whole body except for the face and hands. Adolescent girls who adhere to this conservative dress code in Israel,5 Jordan,6 and Turkey7 have also been reported to have vitamin D deficiency. The effect of low vitamin D levels on productivity could have an important impact on the pace of economic development in rapidly developing countries such as those in the Middle East. If productivity and performance of school children are also affected, there may be public health and occupational health consequences for future generations. With the changing sociocultural environment in these countries, we have yet to see a progressive improvement in vitamin D levels with widening of dietary choices, more women in the workplace, and an increased interest in outdoor activity. The time trends with regard to vitamin D levels in MiddleEastern populations, and an accompanying assessment of productivity levels, may lend further support to the findings of Plotnikoff et al.1 Tar-Ching Aw, MB, PhD Syed M. Shah, MD, PhD, MPH Faculty of Medicine & Health Sciences
Institute of Public Health UAE University, Al-Ain United Arab Emirates
REFERENCES 1. Plotnikoff GA, Finch MD, Dusek JA. Impact of vitamin D deficiency on the productivity of a health care workforce. J Occup Environ Med. 2012;54:117–121. 2. Saadi HF, Dawodu A, Afridi BO, Zayed R, Benedict S, Nagelkerke N. Efficacy of daily and monthly high-dose calciferol in vitamin D deficient nulliparous and lactating women. Am J Clin Nutr. 2007;85:1565–1571. 3. Gannage-Yared MH, Chemali R, Yaacoub N, Halaby G. Hypovitaminosis D in a sunny country: relation to lifestyle and bone markers. J Bone Miner Res. 2002;15:1856–1862. 4. Laleye LC, Kerkadi AH, Wasesa AA, Rao MV, Aboubacar A. Assessment of vitamin D and vitamin A intake by female students at the United Arab Emirates University based on self-reported dietary and selected fortified food consumption. Int J Food Sci Nutr. 2011;62:370–376. 5. Tsur A, Metzger M, Dresner-Pollak R. Effect of different dress style on vitamin D level in healthy young Orthodox and ultra-Orthodox students in Israel. Osteoporos Int. 2011;11:2895–2898. 6. Mallah EM, Hamad MF, El Manaseer MA, et al. Plasma concentrations of 25-hydroxyvitamin D among Jordanians: effect of biological and habitual factors on vitamin D status. BMC Clin Pathol. 2011;11:8. 7. Hatun S, Islam O, Cizmecioglu F, et al. Subclinical vitamin D deficiency is increased in adolescent girls who wear concealing clothing. J Nutr. 2005;135:218–222.
C 2014 by American College of OccupaCopyright tional and Environmental Medicine DOI: 10.1097/JOM.0b013e31825cb6ce
JOEM r Volume 56, Number 4, April 2014 Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
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