Factors affecting the morbidity of vitamin D deficiency rickets and primary protection. Rickets in very-low-birth-weight infants born at Baragwanath Hospital. Double blind study on the need for vitamin D supplementation in prepubertal children.
Rickets was investigated in 860 children in the 3 to 36 month age group in 21 villages attached to Sinik Health Centre, in northeastern Turkey. The blood calcium, phosphorus and alkaline phosphatase levels of suspect cases were determined following examination and wrist x-rays taken. The prevalence of cross-sectional rickets was determined, in the cohort group formed by removing the rickets cases (to the first group, advice was not given; to the second, 400 IU of vitamin D) and its incidence determined. The prevalence of rickets was calculated as 9.8% with no distinction observed between males and females (P > 0.05). It is higher in children in the 3-6 month group (23.97%) (P < 0.05); exposed rarely to the sun (P < 0.001); without fish in diet (P < 0.01); born to mother under 18 years old (P < 0.001); with a mother not using contraception (P < 0.01). The prevalence of acute respiratory infections (ARI) was calculated as 47.62% and 35.70% (P < 0.05) in children with and without rickets, respectively. The prevalence of enteritis was calculated as 29.76% and 18.43% (P < 0.05) in children with rickets and without rickets, respectively. Rickets was not seen where 400 IU of vitamin D was administered, while incidence for the twelve-month period was calculated as 3.8% in the other group. Combatting rickets is important in developing countries where deaths under five years are largely due to ARI and enteritis. Disturbed mineral and bone metabolism has been reported to occur frequently in very-low-birth-weight infants fed breast-milk during the first 3 months of life. This study was designed to assess the prevalence of disturbed mineral homeostasis in a breast-milk-fed very-low-birth-weight population at Baragwanath Hospital and to determine whether the addition of a preterm infant formula to the feeds would reduce this prevalence and increase the rate of weight gain. Fifty-three neonates weighing less than 1 200 g at birth were monitored for weight gain, growth and biochemical and radiological evidence of metabolic bone disease at 2-weekly intervals during hospitalisation and for 18 weeks after discharge. The infants were randomised at 2 weeks of age to receive either breast-milk only, or a combination of breast-milk and a premature formula containing 550 mg calcium and 300 mg phosphorus. All infants received 800 IU vitamin D daily from day 14. Weight gain and growth were similar in both groups. Calcium and phosphorus intakes were higher in the mixed feeding group, but did not affect serum mineral levels. Radiological rickets was uncommon in both groups although periosteal reactions and osteopenia occurred frequently and with similar prevalences. Vitamin D deficiency was not found to be a problem. In conclusion, overt rickets is not a major problem in very-low-birth-weight infants born at Baragwanath Hospital, although biochemical abnormalities occur frequently.(ABSTRACT TRUNCATED AT 250 WORDS) Fifty-one healthy prepubertal schoolchildren were followed for 13 months in a double blind study. Twenty-four of them were supplemented with 400 IU of vitamin D2 5-7 times weekly, while 27 received a placebo. The children were examined in winter both at the beginning and at the end of the study, and in the middle of the study in autumn. Mean 25-hydroxyvitamin D levels in the supplemented group were significantly higher than those in the placebo group both in autumn and in winter, when the study ended. The vitamin D supplementation did not, however, affect other vitamin D metabolites, serum calcium, albumin, inorganic phosphorus, parathyroid hormone concentrations or alkaline phosphatase activity. Moreover, the supplementation caused no alterations in the weight or height gain or bone mineral content of the distal radius of the children, and thus subclinical rickets could not be shown.
There a only few studies on the prevention of nutritional rickets in term born children. Until new data become available, it appears sound to offer preventive measures (vitamin D or calcium) to groups of high risk, like infants and toddlers; children living in Africa, Asia or the Middle East or migrated children from these regions into areas where rickets is not frequent. Due to a marked clinical heterogeneity and the scarcity of data, the main and adverse effects of preventive measures against nutritional rickets should be investigated in different countries, different age groups and in children of different ethnic origin.