Calcium and Phosphorus Metabolism in Osteomalacia Ix. Metabolic Behavior of Infants Fed on Breast Milk from Mothers Showing Various States of Vitamin D Nutrition.

It is generally recognized that the nutritional state of the mother has an important influence upon that of the infant. This influence is exerted during the antenatal period as well as during infancy when breast feeding constitutes the only or main source of nutrients. Among the numerous nutritive factors, those concerned in bone metabolism, namely, calcium, phosphorus and vitamin D, have recently received considerable attention. It has long been suspected that mothers with osteomalacia may give birth to children showing evidence of disturbed calcium and phosphorus metabolism in utero or in early infancy. In 1930 Maxwell and Turnbull (16) reported 2 cases of fetal rickets. The mothers of both children were suffering from advanced osteomalacia with marked pelvic deformities necessitating cesarean section. The infants showed evidence of rickets by x-ray, and one of them, on histological examination of the bones, exhibited deficiency in provisional calcification, irregularity of endochondral ossification from the diaphysis and slight fibrosis in the metaphysis characteristic of rickets. This is the first demonstration of the existence of fetal rickets in infants born of osteomalacic mothers. Subsequent collections of Maxwell and co-workers (17, 18, 19) have added 15 more such cases, establishing beyond doubt the causal relationship between osteomalacia in the mother and rickets in the newborn. In fact, Maxwell (18) says that fetal rickets is certainly to be looked for where the product of serum calcium and phosphorus in the mother is below 20, especially if the calcium factor is distinctly low. Tetany, another manifestation of vitamin D deficiency, tends to occur early in infancy among the cases observed here. In Chu and Sung's analysis (3) of 45 cases of infantile tetany, 30 cases or 66.7 per cent appeared within the first three months of life. In view of the fact that in Europe and America spasmophilia, the identity of which with infantile tetany has been controversial, is more frequently seen after the age of six months, the much earlier age incidence of this condition in North China is probably significant. In looking for an explanation of this unusual observation, they investigated the diet, mode of living and health condition of the mothers, and found that the majority of these women subsisted on diets deficient, among other things, in calcium and vitamin D, or had frank osteomalacia or tetany. This finding suggests to Chu and Sung that the high incidence of tetany in the early months of infancy may be accounted for by a congenital deficiency of vitamin D and calcium. While the importance of antenatal deficiency in the manifestation of the disease cannot be denied, neonatal nutrition as influenced by the condition of the milk of the mother probably also has a significant bearing on the problem. In order to determine how the state of vitamin D nutrition of the mother during lactation affects that of the infant, opportunity has been taken to study the calcium, phosphorus and nitrogen metabolism of both the mother and the infant simultaneously in four instances. The results from the four sets of cases, though similar in demonstrating the intimate relationship between infantile and maternal metabolism during the nursing period, are sufficiently varied to be useful in illustrating the different aspects of the problem: