The effect of sunlight upon the concentration of calcium and of inorganic phosphorus of the serum of rachitic children

Recent studies have shown that the bone lesions of rickets may be healed by a variety of measures (administration of a proper diet, or of cod liver oil, radiation with mercury vapor quartz lamp, carbon arc lamp, cadmium open spark, etc.) Hess and Unger 1 claim to have obtained a similar result by exposing children suffering with rickets to direct sunlight.

Howland and Kramer 2 have demonstrated that with active rickets, unassociated with tetany, there occurs regularly a marked reduction of the concentration of inorganic phosphorus in the serum. In some instances there was also a moderate reduction of the calcium concentration. With active rickets the reduction is such that when the concentration of calcium expressed in mg. per 100 c.c. of serum is multiplied by that of inorganic phosphorus similarly expressed, the product does not exceed the value 30. When healing takes place the concentration of each element approaches the normal so that the value of the product is 40 or above. Since the calcium concentration in normal serum rarely exceeds 11 mg. per 100 c.c. of serum and that of inorganic phosphorus does not go beyond the upper limit of 6 mg. in the same volume of serum the product practically never exceeds the value 66.

The present study was undertaken:

1. To test the curative action of direct sunlight upon rachitic changes in the bones of children.

2. To determine whether the pigmented skin of the negro interfered with the therapeutic action of the sun's rays.

3. To deinonstrate whether direct sunlight is capable of producing as definite an increase in the concentration of calcium and inorganic phosphorus in the serum as occurs with the agents above named.

Although Hess and Unger 1 claim to have produced healing of the rachitic prccess in the bones in from four to six weeks, Hess and Gutman 3 failed to find any significant changes of the inorganic phosphorus of the whole blood when children were exposed to sunlight for the same period.