Low serum calcium levels occur in Nigerian adults with type 2 diabetes and correlates negatively with their glycosylated hemoglobin levels: A case-control study

Background: The prevalence of diabetes mellitus (DM) has increased globally making it a major public health concern. Serum calcium levels, together with other minerals, play an important role in the regulation of plasma glucose. The aim of this study was to determine the serum calcium levels in individuals with Type 2 DM (T2DM) as well as its relationship with their clinical characteristics and glycemic control. Materials and Methods: This was a cross-sectional study carried out at the University of Nigeria Teaching Hospital, Enugu State. A total of 300 participants were recruited, comprising 150 participants with DM and 150 age- and gender-matched normal participants as control. A questionnaire was administered to obtain clinical characteristics. Serum calcium and glycosylated hemoglobin (HbA1c) were measured. Mean ± standard deviation was calculated, and an independent t-test was used to determine the mean difference. Pearson's correlation was done to establish the correlation between serum calcium and HbA1c. Data were analyzed with SPSS version 23. Results: This study showed that the mean serum calcium level for the T2DM participants was significantly reduced (2.16 ± 0.17) when compared to that of the controls (2.21 ± 0.17)(P= 0.02). Furthermore, individuals with T2DM showed a significant negative correlation between serum calcium levels and HbA1c-a long-term measure of glycemic control (r = 0.273; P = 0.001). Conclusion: Participants with T2DM were found to have a lower mean level of serum calcium. In addition, T2DM participants who had poor glycemic control were more likely to have hypocalcemia.