Neither latitude , region of the world , nor laboratory methodology were found to be associated with the prevalence of hypovitaminosis
BACKGROUND Hypovitaminosis D is considered a global public health issue .
Knowledge of its true dimensions will allow us to design interventions and plan preventive measures that can have a significant impact on human health .
OBJECTIVES The aim of this study was to evaluate the prevalence of hypovitaminosis D , defined as a serum 25-hydroxyvitamin D concentration < 30 ng/ml , in postmenopausal women around the world , as well as to identify the potential associated factors .
Vitamin D and skin physiology: a D-lightful story.
Throughout evolution , exposure to sunlight and the photo synthesis of vitamin D(3 ) in the skin has been critically important for the evolution of l and vertebrates . During exposure to sunlight , the solar UVB photons with energies 290 - 315 nm are absorbed by 7-dehydrocholesterol in the skin and converted to previtamin D(3 ) . Previtamin D(3 ) undergoes a rapid transformation within the plasma membrane to vitamin D(3 ) . Excessive exposure to sunlight will not result in vitamin D intoxication because both previtamin D(3 ) and vitamin D(3 ) are photolyzed to several noncalcemic photoproducts . During the winter at latitudes above approximately 35 degrees , there is minimal , if any , previtamin D(3 ) production in the skin . Altitude also has a significant effect on vitamin D(3 ) production . At 27 degrees N in November , very little ( approximately 0.5 % ) previtamin D(3 ) synthesis was detected in Agra ( 169 m ) and Katm and u ( 1400 m ) . There was an approximately 2- and 4-fold increase in previtamin D(3 ) production at approximately 3400 m and at Everest base camp ( 5300 m ) , respectively . Increased skin pigmentation , application of a sunscreen , aging , and clothing have a dramatic effect on previtamin D(3 ) production in the skin . It is estimated that exposure in a bathing suit to 1 minimal erythemal dose ( MED ) is equivalent to ingesting between 10,000 and 25,000 IU of vitamin D(2 ) . The importance of sunlight for providing most humans with their vitamin D requirement is well documented by the seasonal variation in circulating levels of 25-hydroxyvitamin D [ 25(OH)D ] . Vitamin D deficiency [ i.e. , 25(OH)D < 20 ng/ml ] is common in both children and adults worldwide . Exposure to lamps that produce UVB radiation is an excellent source for producing vitamin D(3 ) in the skin and is especially efficacious in patients with fat malabsorption syndromes . The major cause of vitamin D deficiency globally is an underappreciation of sunlight 's role in providing humans with their vitamin D(3 ) requirement . Very few foods naturally contain vitamin D , and those that do have a very variable vitamin D content . Recently it was observed that wild caught salmon had between 75 % and 90 % more vitamin D(3 ) compared with farmed salmon . The associations regarding increased risk of common deadly cancers , autoimmune diseases , infectious diseases , and cardiovascular disease with living at higher latitudes and being prone to vitamin D deficiency should alert all health care professionals about the importance of vitamin D for overall health and well being
Neither latitude , region of the world , nor laboratory methodology were found to be associated with the prevalence of hypovitaminosis
BACKGROUND Hypovitaminosis D is considered a global public health issue .
Knowledge of its true dimensions will allow us to design interventions and plan preventive measures that can have a significant impact on human health .
OBJECTIVES The aim of this study was to evaluate the prevalence of hypovitaminosis D , defined as a serum 25-hydroxyvitamin D concentration < 30 ng/ml , in postmenopausal women around the world , as well as to identify the potential associated factors .