Martha M. Eliot

A study of the comparative value of cod liver oil, viosterol, and vitamin D milks in the prevention of rickets and of certain basic factors influencing their efficacy

Summary 1. This paper reports an investigation of the relative efficacy of several different forms of vitamin D at different dosage levels. The study was carried out in Detroit, Mich., during the winter months of 1933–36. Five hundred sixty-seven full-term infants were observed from approximately one through six and one-half months of age. They were given either cod liver oil or viosterol or some form of vitamin D milk at different dosage levels. The dosage administered varied considerably, from approximately 150 through 3,000 U.S.P. units. Diagnosis was based on x-ray films of the bones of both forearms, taken at approximately monthly intervals. 2. The results of this study have demonstrated the necessity of consideringsuch factors as color, sex, rate of growth in length, period of observation, and interval between examinations as basic when attempting to evaluate the efficacy of certain types of antirachitic substances administered at different dosage levels in the prevention of rickets. 3. The evidence presented referes almost exclusively to the incidenceof slight rickets as the dosage level was sufficiently high to prevent the development of moderate or marked rickets except in a few infants. 4. The incidence of rickets was significantly less among the colored infants than among the white. The same tendency was found consistently among infants given the different antirachitic agents both when all dosage levels were combined and, with few exceptions, at the different dosage levels. 5. When pertinent basic factors were taken into consideration, it became apparent that, in spite of their lower dosage level, the milks, especially those at the 400 unit level, tended to be more effective in the prevention of rickets than cod liver oil. There is also evidence that viosterol is at least as effective as cod liver oil, and no evidence that cod liver oil is superior to viosterol, unit for unit, in the prevention of rickets. 6. There is no definite evidence from this study that one type ofmilk at the 400 unit level is superior to another in the prevention of rickets. For the lower dosage levels no clear-cut conclusions with regard to comparative efficacy can be drawn. 7. Within the dosage range used for each type of antirachitic, the higher dosage levels appear to be more effective, provided the basic factors mentioned above are taken into consideration. 8. Advance in the rachitic process occurred most frequently in infants receiving cod liver oil, least frequently in those given vitamin D milk. 9. Regression or healing of the slight degrees of rickets discussedin this paper tended to occur more promptly in infants receiving vitamin D milk of the higher (400 units) dosage level than in those receiving that of the lower level (150 units). Of the different types of vitamin D milk containing 400 units, that to which viosterol was added appeared to be the most efficient. This form also tended to be more efficient than viosterol alone even when the latter was given at a somewhat higher level. When given at a dosage level of approximately 675 units, viosterol tends to bring about regression of slight rickets more promptly than cod liver oil at the same dosage level. 10. The incidence of slight rickets has been shown to be closely and consistently related to growth in length when the dosage of the antirachitic is relatively high, whereas for infants in the lower dosage group there is no consistent difference in the incidence of rickets. These findings indicate that at the higher level the balance between rickets-producing and rickets-preventing factors has been stabilized to such an extent as to allow rate of growth in length to become evident. On the other hand, when a smaller amount is given, the effect of the growth in length is lost in the stronger influence of the inadequate amount of vitamin D. 11. It would appear that if rickets is to be prevented or promptly controlled an amount of vitamin D must be given that will assure stability in the metabolic processes providing for normal bone growth and allow an adequate margin of safety for the rapidly growing infant. From the data here presented, this amount would appear to be at least as high as that contained in the usual dose of cod liver oil; namely, two to three teaspoonfuls. Finally in evaluating the results of such a study as this one, it should be borne in mind that from the public health point of view, as well as that of the individual infant, the value of a substance containing vitamin D should be measured first in terms of success in the prevention of rickets under practical conditions and second in terms of economy, and that such economic considerations must include not only the cost of the vitamin but also the need and cost of other nutrients supplied by the vehicle carrying vitamin D.

The Control of Rickets

THAT ANIMALS CAN BE protected against rickets by the use of cod liver oil and ultraviolet rays is an established fact. It has also been clearly shown that cod liver oil and sunlight exert a great influence in the cure of rickets. Whether these measures are sufficient to prevent rickets in infants in a community is the problem on which we are working in the demonstration in New Haven. It is my purpose to set forth briefly the plan of the study and to offer a preliminary discussion of the results.