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Vitamin D and Health in the 21st Century

October 9-10, 2003
NIH Conference
Bethesda, Maryland

Background

Vitamin D is an essential nutrient that is unique, both in terms of its metabolism/physiology, and the human reliance on both endogenous production and exogenous sources to meet biological requirements. It is the interaction between the two primary sources of biologically active vitamin D that has historically been the focal point of public policy aimed at meeting the population requirements and the amelioration of environmentally mediated epidemics of vitamin D deficiency, i.e., vitamin D-related rickets.

Recently, evidence has been published indicating a re-emergence of vitamin D-deficient rickets and an alarming prevalence of low circulating levels of vitamin D in the United States population. Until the revelation of these data, it had been assumed that vitamin D deficiency had been eliminated as a significant problem, and that the strategies used to achieve this success (i.e., food fortification) served as role models of successful public health interventions. Speculation about factors that may be contributing to the rise in vitamin D deficiency (i.e., significantly reduced levels of circulating vitamin D) and vitamin D-related rickets in the United States and internationally) has included the following:

A perception, unsubstantiated by population-based surveillance data, of a high prevalence of lactose intolerance leading to undesirable effects from consumption of milk and dairy foods, particularly among African Americans
Lower intake of vitamin D-fortified foods, particularly fluid mild and fortified cereals
Concerns about fat intake contributing to reduced intake of vitamin D-fortified foods, such as milk
Reduced intake of calcium-rich foods, including milk in adolescents and young women of reproductive age, contributing to decreased concentrations of vitamin D and calcium in those populations
An increase in the use of sun block and decreased exposure to sunlight to reduce the risk of skin cancer due to exposure to ultraviolet (UV) radiation
Increased prevalence and duration of exclusive breastfeeding; the combination of human milk being a poor source of vitamin D and the high prevalence of low circulating vitamin D levels in U.S. women, particularly African American mothers, resulting in an increased risk of vitamin D deficiency
Indications of decreased vitamin D status associated with decreased UV exposure due to increased air pollution in newly emerging industrialized countries in the developing world
Impact of food insecurity (i.e., limited access and availability to calcium-rich and/or vitamin D-fortified foods) in resource-poor settings in the developing world

The current situation regarding vitamin D status and the development of effective policies to address problems associated with vitamin D insufficiency in the United States and internationally reflects data needs regarding several key issues, including:

Lack of biological data to develop meaningful, racially relevant dietary requirements to achieve vitamin D nutritional/dietary adequacy;
Inadequate knowledge about the functional impact of low circulating levels of vitamin D throughout the life cycle;
The impact of the environment on vitamin D status; and
An understanding of the impact of the unique confluence of influences from several public health policies that has resulted in an unintended adverse health outcome (i.e., efforts to decrease risk of skin cancer from exposure to radiation, attempts to increase prevalence and duration of exclusive breastfeeding, etc.).

A number of outstanding issues create a hindrance to the promulgation of meaningful public health policy in this regard. Many of these issues were identified by an Expert Panel convened by the Centers for Disease Control and Prevention (CDC) and include:

Epidemiology/Demographics

Adequacy of data regarding prevalence of vitamin D deficiency in the United States/internationally
Methodology for assessing vitamin D status
Biomarkers of vitamin D status

Biological Issues

The need for a sound knowledge base to determine vitamin D needs of various segments of the population and factors capable of making an impact
The lack of data on the functional consequences of low circulating concentrations of vitamin D throughout the life cycle, but particularly in women, infants, and children
Identification of essential data needs to establish realistic, meaningful dietary requirements for vitamin D with particular reference to different ethnic/racial group, such data needs might include consideration of potential genetic polymorphisms in vitamin D metabolism and racial differences in vitamin D requirements
Particular attention should be paid to specific ethnic groups and practitioners of specific cultural practices to determine whether and how ethnicity and practices may impact vitamin D status, and perhaps contribute to documented health disparities among these groups and the general population
The adequacy of the evidence base to support a decision regarding food sources of vitamin D, and the need for supplementation of selected target groups both domestically and internationally
Data needs to allow decisions about whether high-dose supplementation of mothers, infants, or both will work to prevent vitamin D deficiency in infants, and for which groups it is feasible; among the considerations is that, if supplementation found to be warranted, what would be the best dose and method; this topic would include discussions of efficacy and safety both domestically and internationally

Public Health Implications

How to best achieve the goals of existing public health messages, e.g., reduction of exposure to UV radiation, and still achieve adequate vitamin D status
How to best ensure vitamin D adequacy of lactating mothers and their infants in the context of current public health policy regarding breastfeeding both in the United States and internationally
An examination of the impact of changes in public policy in the United States on international food and nutrition policy related to infant feeding practices

The two-day conference is organized to achieve the following goals:

To present current data/research about the prevalence of vitamin D deficiency
To determine the critical research needs in the evaluation of vitamin D biology
To determine data needs for establishing dietary requirements across the full developmental spectrum but with particular attention to women, infants, and children
To assess factors affecting and current options for improving vitamin D status of women, infants, and children in the United States and internationally

By addressing these goals, the organizers will develop a focused research program that will provide data essential for the promulgation of evidence-based public policy about achieving vitamin D adequacy in the United States and elsewhere.

The opening session of the conference will include: overview presentations about the epidemiology of vitamin D deficiency in the United States and internationally; an overview of vitamin D biology; and current policies and how they may be impacting on the vitamin D status of women and infants in the United States.

Consistent with themes developed during previous NIH workshops on dietary supplement use, the agenda of this conference will include discussions of four key topical areas from a developmental and methodological perspective. The thematic topics include

Monitoring and data needs;
Developmental physiology;
Critical examination of data implicating vitamin D in a variety of adverse health outcomes including osteoporosis, cancer, and other disorders of public health significance; and
Behavioral, cultural, and public-policy factors influencing choice of intervention to address potential vitamin D insufficiency in women, infants, and children.
In addition to the plenary papers, each session will include a panel of experts charged with addressing a predetermined set of core questions regarding research needs.

The session panel discussions are intended to be interactive opportunities for cross-fertilization of ideas between a panel of experts on the subjects covered in the plenary session, and the audience. Panels will consist of plenary speakers, additional members as identified by session chairs, and the session chair. Panels will be charged with reaching some conclusions with regard to pre-assigned questions. To encourage active dialogue and a productive group dynamic, each panel member will be provided a brief opportunity to present current thinking on the subject topic.

At the end of each session, session chairs will summarize the results of the deliberations and identify three-to-five future research priorities. The summaries will become part of the official meeting record and will be used by the conference organizers for program-planning activities and compilation of the conference proceedings.

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This conference will be of interest to policy makers, consumers, clinicians, and academics with a background and/or interest in vitamin D.

The NIH/FAES is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The NIH/FAES designates this educational activity for a maximum of 12 category 1 credits toward the AMA Physician's Recognition Award. Each physician should claim only those credits that he/she actually spent in the activity.

Application has been made for 11.5 Continuing Professional Education Units from the American Dietetic Association (ADA).