Vitamin D deficiency in the United States: a growing epidemic with serious health consequences.

Until recently, the importance of vitamin D deficiency has focused on the incidence of rickets occurring in children and on osteomalacia occurring in the adult population. In addition, past research efforts focusing on vitamin D deficiency has linked suboptimal serum levels to heart disease, cancer, infection, and poor health overall. Over the past 20 years serum levels of vitamin D (25)(OH) have dropped significantly in the US population. A research team lead by Dr Adit Ginde at the University of Colorado Denver School of Medicine examined serum vitamin D levels in a large group of individuals who resided in the United States. Different races were included. All participants’ data came from the Third National Health and Nutrition Examination Survey (NHANES 111). These investigators collected data from 18,883 individuals from 1988 through 1994 and from an additional group of 13,369 individuals whose date collection started in 2001 ending in 2004. Results were interesting. Dr Ginde stated that the team discovered ‘‘a marked increase in vitamin D deficiency’’ and that ‘‘three out of every 4 adult and adolescent individuals are deficient. Americans now have levels below what are believed to be necessary for optimal health’’ African Americans and Hispanics are at a particularly high risk. Nearly all have ‘‘suboptimal levels.’’ Additional findings revealed that the mean vitamin D levels averaged 30 ng/mL (95% CI) from 1988 through 1994 but dropped to an average of 24 ng/mL between 2001 and 2004. Current recommended daily intake set forth by the Institute of Health are as follows: 200 IU/d from birth to age 50, 400 IU/d for those aged 51 to 70 years, and 600 IU/d for those aged 71 years and over. At present acceptable optimal serum levels for vitamin D are 50 to 80 mg/mL. Dr Ginde states that ‘‘vitamin D is an important and unappreciated public health issue and may be responsible for some racial differences in health outcome.’’ Factors that contribute to lower serum levels are; the use of sun blocks, the age of an individual, body weight, percentage of body fat, skin color, season of the year, and the variation in sun exposure. In addition, Dr Ginde adds ‘‘ more Americans could use more vitamin D; and higher doses of supplementation than currently recommended’’ Ginde feels that 1000 to 2000 IU daily are like needed to raise the serum levels in many individuals. Obese individuals may require a higher intake because fat sequesters vitamin D. Equally important is to realize that those living at higher altitudes and in certain other geographic locations have limited exposure to sunlight; especially during winter months and need to be considered. Comment: Additional large, controlled randomized trials with eventual meta-analysis need to be done. Trials involving increase oral intake of vitamin D need to be conducted to look for changes in morbidity and mortality rates in the US population possibly attributed to suboptimal levels of this important vitamin. From the Cardiovascular Research Institute, University of California at San Francisco, San Francisco, CA Address for correspondence: Donna J. Drown, RN, MSN, Cardiovascular Research Institute, University of California at San Francisco, 505 Parnassus Avenue, L-1337, San Francisco, CA 94143-0130 E-mail: ddrown@pacific.net September 2009 Progress in Cardiovascular Nursing