THE REEMERGENCE OF VITAMIN D DEFICIENCY RICKETS-THE NEED FOR VITAMIN D SUPPLEMENTATION

Abstract

Vitamin D deficiency rickets was first described in England around 1650. The Industrial Revolution caused poor people to be concentrated in narrow sunless alleys of crowded factory towns and big city slums and the use of soft coal caused smoke filled skies. In the United States 13,807 deaths in infants under the age of 12 months were attributed to rickets between the years of 1910 and 1961. In 1932, 50% of white children and 88% of black children were found to be rachitic. 1 With the introduction of vitamin D fortified milk and formulas and the routine use of fish liver oils and other forms of vitamin D supplementation, vitamin D deficiency rickets all but disappeared by the 1960's and was deemed a “medical curiosity” in pediatric clinics. 2 In recent years, however, this debilitating disease of infants and children has shown evidence of reemergence. The prevention of rickets has been a triumph of modern science and public health but little is known of the history. The association between rickets and a deficiency in solar radiation was observed in the late 1800's when the seasonal variation of rickets was termed a “sickness of domestication” from “living locked indoors” and that the habitat of a child is “being disturbednamely the outdoors”. The absence of rickets in areas of constant sunshine, in spite of the presence of poor diet and poor sanitation, provided further evidence that lack of sunshine, not diet, was responsible for the development of vitamin D deficient rickets. A brilliant experiment of Jan Raczynski in 1912 pointed to lack of sunlight as the principal causative factor in rickets when newborn puppies fed exclusively on milk of their mother were reared either in sunlight or in deep shade. After six weeks, those puppies kept out of sunlight became markedly rachitic. The discovery by Huldschinsky in 1919 that UV radiation not only cured rickets in the irradiated arm of a rachitic child but in the other arm as well, proved that irradiation of the skin released a chemical into the bloodstream that could induce healing at a distant site-a hormone, by definition. In 1927, Otto Rosenheim and Thomas Webster showed that the plant sterol ergosterol became enormously antirachitic when irradiated with ultraviolet light. With this discovery, it became routine to add ergocalciferol to all milk sold in the U.S. and most European countries. A description of the skin hormone naturally released by irradiated skin was provided in 1936 when it was demonstrated that 7-dehydrocholesterol was the natural prehormone in skin that becomes calciferol on UV irradiation. Rickets is best compared to an endocrine-deficiency disease rather than a vitamin deficiency disease. 3 How then did vitamin D deficiency rickets be