Calcium and Albumin Blood Tests, Ethnicity, and Cancer Incidence in Primary Care in the UK

Objectives: This study aimed to assess any ethnic differences in blood calcium and albumin levels for patients receiving these tests in primary care, and to investigate how this affects the use of these markers in assessing cancer risk. Methods: The analysis was based on a primary care dataset comprising patients in England. Multilevel logistic regression was used to investigate the relationship between blood test results and cancer risk by ethnic group. Results: A total of 4,632,856 patients were eligible for the albumin analysis, and 1,979,763 for the calcium analysis. Raised calcium levels were indicative of an increased risk of cancer, with diagnostic odds ratios (ORs) ranging from 2.0 to 2.7 for the different ethnic groups. ORs for myeloma were between 6.6 and 13.6. Similarly, low albumin was associated with an increased risk of cancer with an OR of between 3.2 and 3.8, myeloma (OR between 8.7 and 10.0), and liver cancer (OR between 9.2 and 15.7). Conclusions: Albumin and corrected calcium were effective indicators of cancer risk, and more specifically of risk of myeloma. Albumin levels were also linked with liver cancer risk. While there are some differences in typical corrected calcium and albumin levels between ethnic groups, there was no evidence that this had an effect on the usefulness of these markers to infer cancer risk.