Posted : 02/01/2000

UVR &The Vitamin D Conundrum

by Donald L. Smith

The following article is the third in a series that will deal with the incontrovertible benefits of sensible, moderate and responsible exposure to UVR. This article shows that UVR-induced vitamin D helps protect us from developing osteoporosis.

The Osteoporosis/Vitamin D Conundrum

A conundrum is defined as anything that puzzles or confuses. Thus, it most definitely is puzzling and confusing to read articles in scientific journals about osteoporosis. Although they inevitably state that osteoporosis can result from sub-optimal levels of vitamin D and agree that this situation is exacerbated by inadequate exposure to sunlight, most authors then state that potentially toxic vitamin D supplements should be used. Why don't authors just recommend that individuals with sub-optimal vitamin D levels get more exposure to sunlight or visit a tanning salon? Of course we already know the answer to that question. First of all, osteoporosis researchers usually are endocrinologists who do not want to incur the wrath of the dermatology community by recommending UVR exposure. In addition, many researchers are supported by grants from drug companies who are trying to develop a synthetic vitamin D analog that would be as effective as the cutaneously produced form. It must be kept in mind that all known vitamin D analogs are toxic to humans while the vitamin D that is produced naturally by the action of UVR on the skin is not.

What Wonderful News

The conundrum described above explains why I was so excited when I read the article "Interim Report and Recommendations of the World Health Organization (WHO) Task-Force for Osteoporosis" in the Nov. 4, 1999 issue of Osteoporosis International. The task-force is a who's who of international osteoporosis researchers and Harry K. Genant, M.D., who is the executive director of the Osteoporosis and Arthritis Research Group at the University of California in San Francisco, serves as the task-force chairman.

The WHO Task-Force Goal

The cornerstone of the project is the development of a master document on osteoporosis management and prevention. This documentation, developed in collaboration with leaders in osteoporosis research and patient care worldwide, will be reviewed by the major academic, governmental and non-governmental organizations concerned with osteoporosis before being submitted for approval by the WHO. A series of practical guides for osteoporosis management will be prepared from the master report. The guides are intended for the use of primary care physicians worldwide, and will be translated and adapted for clinical use in different cultures, medical communities and countries.

WHO Definition Of Osteoporosis

Osteoporosis is a systemic skeletal disease characterized by low bone density and microarchitectural deterioration of bone tissue. The consequent increase in bone fragility greatly increases the risk of fractures which represent the major relevant clinical aspects of the disease. Osteoporosis affects mainly post-menopausal women, but also can affect men. There are three major fracture sites in osteoporosis--the hip, the vertebrae and the distal radius. Hip fractures are known to have a high morbidity and mortality and their absolute number is expected to almost quadruple in the next 25 years.

The Osteoporosis Problem Worldwide

An estimated 1.7 million hip fractures occurred worldwide in 1990. Due to increasing population and inverted life expectancy, that number is expected to exceed 6 million by 2050. Currently, the majority of hip fractures occur in North America and Europe; however, demographic shifts over the next 50 years will lead to huge increases in the number of elderly in Asia, South America and Africa. Consequently, there will be a shift in the burden of the disease from the developed to the developing world.

The Osteoporosis Problem In The U.S.

There were 250,000 hip fractures in the United States in 1990 with approximately 50,000 deaths from complications occurring within the first six months after the accident. More than 50,000 individuals who survive are unable to walk without assistance and an additional 50,000 of the survivors subsequently require long-term nursing home care.

By 2010, there are projected to be more than one million hip fractures each year in the United States as the baby boomers in the population reach retirement age. Therefore, osteoporosis represents a major challenge to the financial stability of the U.S. health care system due to the fact that the annual cost currently is estimated to be more than $10 billion per year. In addition, this total is projected to explode to $40 billion per year by 2010.

The Heart Of The Problem

Low calcium intake and/or insufficiency of vitamin D due to inadequate sunlight exposure may accelerate bone loss, probably by enhancing the secretion of parathyroid hormone.

The following statement by Zane Kime, M.D., M.S., in his book Sunlight, is the best explanation of the interdependent relationship between calcium and vitamin D.

"If vitamin D is absent, calcium, which is vital for normal bone growth and development, will not be absorbed from the intestinal tract and the bones will become deformed. In children the condition is termed rickets, and in adults it is referred to as osteomalacia or osteoporosis. Either of these disease conditions can occur if calcium and phosphorus are deficient in the diet, or if the minerals are present but vitamin D is absent. Healthy bones then are dependent upon a supply of calcium and phosphorus, the absorption of which is dependent upon the present of vitamin D, which in turn is dependent upon one's exposure to the sun.

WHO Task-Force Recommendations

As you can see from the WHO Task-Force recommendations listed below, there now is a call for "adequate exposure to sunlight," which bodes well for the indoor tanning industry. Granted, it is a very small step from the acceptance by the North American public that they need more exposure to sunlight to an understanding and acceptance of the fact that the most convenient and cost-effective source of UVR year-round is the friendly local indoor tanning salon.

WHO Recommendations

• Maintain a physically active lifestyle with adequate exposure to sunlight, particularly elderly and high-risk persons in northern latitudes.
• Avoid smoking and high alcohol intakes.
• Maintain a dietary calcium intake which meets or exceeds the relevant Recommended Dietary intakes in the country or region concerned.
• Maintain a Body Mass index of not less than 19 kg/m2

What Does The Indoor Tanning Industry Need To Do?

Three of the Tanning Research Fund goals are:

• To verify and confirm that optimal levels of vitamin D can be produced and maintained by routine controlled exposure to UVR.
• To ascertain the tanning frequency required to produce and maintain optimal levels of vitamin D.
• To investigate whether or not clients over 50 years of age require more frequent tanning sessions in order to maintain optimum levels of vitamin D.

All three of these projects will provide scientific evidence that we can use to support the fact that the benefits of sensible, moderate and responsible exposure to UVR far outweigh the minimal and manageable risks, especially in the prophylactic treatment individuals at high risk of developing osteoporosis. All of our research will be conducted at two or more sites in order to assure the integrity of the data. This "mirror imaging" adds to the cost of our research; however, it will be well worth it when the study data is published and submitted to the appropriate governmental entities.

What Can You Do?

Resolve to send a contribution and/or pledge to the Tanning Research Fund by calling (888) 994-3828. In addition, request information about the $200,000 in 2000 Challenge or go to our Web site located at www.naatso.org.

These projects will provide scientific evidence that we can use to support the benefits of sensible, moderate and responsible exposure to UVR.

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Donald L. Smith