Ethnicity and social deprivation contribute to vitamin D deficiency in an urban UK population

Abstract

We receive a large number of 25 hydroxyvitamin D (25OHD) assay requests from General Medical Practitioners (GPs) in primary care. We have investigated whether this rate of requesting is related to the ethnicity of the local urban population based in Central Manchester or Trafford areas with very different ethnic populations. Data on assay requesting was collected from January-December 2013. Samples were assayed using an ABSciex 5500 tandem mass spectrophotometer and the Chromsystems 25OHD kit for LC-MS/MS. 11,291 requests for 25OHD measurement received from Central Manchester GPs and 5176 requests from Trafford GPs. Overall 29% of patients were profoundly deficient (<25nmol/L) and a further 32% were insufficient (25-50nmol/L). Using the 2011 Census data we have analysed our data by ethnicity (categorized here as white, Asian, black, Chinese, other) based on patient's home postcode and related this to the Index of Multiple Deprivation (IMD). In areas where >70% of the population were non-white (NW), 69% had 25OHD <50nmol/L. Areas where <5% of patients were NW, 42% of patients were still insufficient. There was a significant correlation between the Index of Social Deprivation (IMD) and the percentage of patients with 25OHD <50nmol/L (p<0.0001). Areas with the highest Index of Social Deprivation (IMD ranking <16,000) showed no association between ethnicity and IMD (p=0.69). We have shown that over 61% of all patients in these urban areas of Manchester and Trafford showed increased risk of bone, and potentially other diseases, based on their 25OHD assay results alone and that social deprivation, as well as ethnicity, contribute to the poor 25OHD levels seen in these patients.

Keywords: Assay requesting; Ethnicity; Social deprivation; Vitamin D.