Elderly individuals exhibit the highest prevalence of vitamin D deficiency. In industrialized western countries approximately 50 percent of elderly persons (65 years and older) have inadequate 25(OH)D levels varying between 40 – 100% in different study populations (1) (Fig. D4). Recent evidence indicates that children and young adults are also at high risk for vitamin D deficiency. Two studies from the USA reported 48 – 52% of preadolescents and adolescents having 25(OH)D levels below 50 nmol/L (2). Other studies in young and middle aged adults found 32 and 42% of individuals with deficient 25(OH)D levels below 50 nmol/L (3). Of note, the frequency of vitamin D deficiency varies between different geographic areas depending from nutritional habits and sunlight exposure. In areas with the highest sun exposure worldwide, such as Australia, Arabic countries, and India, 30 to 50% of children and adults have 25(OH)D levels of less than 50 nmol/L due to clothing covering most of the skin and the use of sun blocker (4).
Pregnant and lactating women are also at high risk for vitamin D deficiency. In an American study 73% of pregnant women and 80% of their infants were vitamin D deficient although they took a multivitamin containing 400 IU vitamin D during pregnancy. In addition, most of them ate fish and drank more than two glasses of milk per day (5).
1. Holick MF. Vitamin D deficiency. N Engl J Med 2007;357:266-81.
2. Gordon CM, DePeter KC, Feldman HA, Grace E, Emans SJ. Prevalence of vitamin D deficiency among healthy adolescents. Arch Pediatr Adolesc Med 2004;158:531-7.
3. Nesby-O'Dell S, Scanlon KS, Cogswell ME, Gillespie C, Hollis BW, Looker AC et al. Hypovitaminosis D prevalence and determinants among African American and white women of reproductive age: third National Health and Nutrition Examination Survey, 1988-1994. Am J Clin Nutr 2002;76:187-92.
4. McGrath JJ, Kimlin MG, Saha S, Eyles DW, Parisi AV. Vitamin D insufficiency in south-east Queensland. Med J Aust 2001;174:150-1.
5. Wagner CL, Taylor SN, Johnson DD, Hollis BW. The role of vitamin D in pregnancy and lactation: emerging concepts. Womens Health (Lond Engl ) 2012;8:323-40.