RT Journal Article SR Electronic T1 Nutritional rickets in Norway: a nationwide register-based cohort study JF BMJ Open JO BMJ Open FD British Medical Journal Publishing Group SP e015289 DO 10.1136/bmjopen-2016-015289 VO 7 IS 5 A1 Haakon E Meyer A1 Kristina Skram A1 Ingvill Almås Berge A1 Ahmed A Madar A1 Hilde Johanne Bjørndalen YR 2017 UL http://bmjopen.bmj.com/content/7/5/e015289.abstract AB Objectives Poor vitamin D status has been reported to be highly prevalent in many non-western immigrant groups living in Norway and other western countries. However, data on rickets are scarce, and the aim of the current study was to identify new cases of nutritional rickets in Norway in the period 2008–2012 among children under the age of 5 years.Design Register-based cohort study.Setting The Norwegian population from 2008 to 2012.Participants Children with nutritional rickets under the age of 5 years.Main outcome measure Nutritional rickets. Patients with ICD10 (International Statistical Classification of Diseases and Related Health Problems, 10th revision) diagnosis code E55.0 (active rickets) treated at all Norwegian hospitals were identified in the Norwegian Patient Registry. We were able to review 85% of the medical records for diagnosis confirmation. In addition, we identified patients with the diagnoses E55.9, E64.3 and E83.3 to identify individuals with rickets who had been given other diagnoses.Results Nutritional rickets was confirmed in 39 children aged 0–4 years with the diagnosis of E55.0. In addition, three patients with the diagnosis of unspecified vitamin D deficiency (E55.9) were classified as having nutritional rickets, giving a total of 42 patients. Mean age at diagnosis was 1.40 years (range 0.1–3.5 years), and 93% had a non-western immigrant background. The incidence rate of rickets was estimated to be 0.3 per 10 000 person-years in the total Norwegian child population under the age of 5 years and 3.1 per 10 000 person-years in those with an immigrant background from Asia or Africa.Conclusion The number of children with nutritional rickets in Norway remained low in the period 2008–2012. Nearly all children had a non-western immigrant background.