Plasma magnesium in adult asthmatics at the Lagos University Teaching Hospital, Nigeria

Objective: To determine the plasma magnesium levels in adult asthmatics. Design: Case control study. Setting: Lagos University Teaching Hospital, Lagos, Nigeria. Subjects: Forty stable asthmatics and thirty five apparently healthy controls. Methods: Detailed history including drug history was obtained from patients and controls. Fasting venous blood was collected into heparinized tubes from both patients and controls. Plasma magnesium, albumin, calcium and phosphorus were measured using spectrophotometric end point methods. Results: Mean (SD) plasma magnesium concentration of 0.93(0.24) mmol/L in the asthmatics was significantly lower compared to the controls which was 1.15(0.28) mmol/L, p<0.001. There was no significant difference in the plasma albumin, calcium and phosphorus levels between the patients and controls. Plasma magnesium levels correlated with the plasma albumin level (r=0.62) but did not correlate with the duration of disease, peak flow rate and age of patients. There was no gender difference in plasma magnesium levels in the asthmatics. Conclusion: Adult Nigerian asthmatics have lower plasma magnesium concentrations compared to healthy controls. This may be of use in future therapeutic management of asthma. A large scale multi-centre study needs to be carried out since this study was done in one hospital.