A Search for Sub-Clinical Rickets in Glasgow Children

Two random samples of Glasgow children aged 12 to 24 months were examined for clinical, biochemical and radiological evidence of subclinical rickets. No cases of florid rickets were discovered. One-third of the first sample studied (202 children) were estimated to be receiving less than 100 i.u. of vitamin D daily from all sources except sunshine. A poor dietary intake was most prevalent in the higher birth ranks and in social classes II and III (non-manual). The mean serum alkaline phosphatase level was 20 K.A. units per 100 ml. (S.D. 8 units) and 11 per cent had levels of 25 K.A. units per 100 ml. or above. No reason, either dietary or clinical, was found which would account for these high levels. Bone changes were observed in the wrist X-rays of about 9 per cent of children. They disappeared gradually with vitamin D therapy and there is some correlation with a raised alkaline phosphatase level and with tallness. They may be due to a relative insufficiency of vitamin D. Serum alkaline phosphatase estimations and wrist radiography do not appear to be useful methods for estimating the prevalence of hypovitaminosis D in the community or as screening procedures in the detection of individual cases of subclinical rickets.