Role of Serum Magnesium levels in Asthmatic with children

Asthma is a chronic disease of the airways which requires maintenance of long term control. In addition to the given standard treatments, mineral-supplementation therapies, such as magnesium, are being tried to maintain asthma control. Improvement in bronchial responsiveness and quality of life were reported with oral magnesium therapy in patients with asthma [1,2]. The basis of which lies on the important role that magnesium plays in the activity of smooth muscles. Magnesium is the cofactor of more than 300 enzymes and is involved in many physiological functions including protein synthesis, intracellular signal distribution and enzyme catalysis [3]. Since it is the natural antagonist of calcium, it brings about smooth muscle relaxation [4]. In addition, magnesium suppresses the excitability of muscle ibers by reduction of acetylcholine secretion from motor nerve terminals. It also inhibits production of in lammatory mediators by helping stabilization of T-cells and inhibiting mast cell degranulation. Further, it reduces the severity of in lammation in asthma by stimulating nitric oxide and prostacyclin syntheses [5]. The above actions of magnesium suggests a possible role of magnesium de iciency and poor asthma control.


Introduction
Asthma is a chronic disease of the airways which requires maintenance of long term control. In addition to the given standard treatments, mineral-supplementation therapies, such as magnesium, are being tried to maintain asthma control. Improvement in bronchial responsiveness and quality of life were reported with oral magnesium therapy in patients with asthma [1,2]. The basis of which lies on the important role that magnesium plays in the activity of smooth muscles. Magnesium is the cofactor of more than 300 enzymes and is involved in many physiological functions including protein synthesis, intracellular signal distribution and enzyme catalysis [3]. Since it is the natural antagonist of calcium, it brings about smooth muscle relaxation [4]. In addition, magnesium suppresses the excitability of muscle ibers by reduction of acetylcholine secretion from motor nerve terminals. It also inhibits production of in lammatory mediators by helping stabilization of T-cells and inhibiting mast cell degranulation. Further, it reduces the severity of in lammation in asthma by stimulating nitric oxide and prostacyclin syntheses [5]. The above actions of magnesium suggests a possible role of magnesium de iciency and poor asthma control.
However studies conducted to establish this relationship have yielded con licting results. Therefore, there is a need for a study to assess whether magnesium de iciency exists in asthmatic children.

Materials and Methods
This case control study was conducted over a period of 6 months in Ramaiah teaching hospital on a sample of 88 children aged between 6 to 16 years, 44 cases and 44 controls. The cases were children with established asthma visiting the outpatient department and the controls were healthy age and sex matched children. Children with co-existing cardio-pulmonary co morbidities and nutrional de iciencies were excluded from the study.
Informed consent was taken from all the care givers of the patients. Spirometry was performed to determine asthma control. 0.5 mL of heparinized whole blood samples of patients with broncho constriction and healthy children who met the inclusion criteria was drawn before using any medication and was immediately sent to the laboratory. Serum magnesium levels were quanti ied by colorimetric method with chlorophosphonazo.
Frequency distribution, percentage distribution, mean +/-SD, Pearson's comparison co-ef icient was calculated with 95% con idence intervals for the comparison of the indings of case and control groups.

Results
The data hence collected was systematically tabulated and analyzed with SPSS software. The descriptive statistics for the case and control group. The over all levels of serum magnesium is lower in the case group with the mean among the cases 1.9136±0.44 and 2.0042±0.26 among the controls. Further, 32% of the cases had lower than normal values of serum Magnesium.
On calculation of Pearson's correlation coef icient, the FEV1% of the cases were found to have a positive correlation with serum magnesium levels, r=0.819, P<0.001. This implies that with rise in FEV1%, the serum magnesium levels rise.

Discussion
This study explores the possibility of low serum magnesium level being a factor in the pathogenesis of asthma and its role in maintaining adequate control to prevent exacerbations. Serum magnesium levels of 32 % of cases were lower than normal as opposed to 0% in the control group. Even though, majority of the cases had magnesium levels within the normal range, the mean serum magnesium levels of the case group is statistically lower than that compared to the control group. Pearson's correlation suggests a statistically signi icant positive relationship between serum magnesium levels and FEV%, a inding unique to this study. This suggests that with increase in the serum magnesium levels, lung function tests improve. This strati ies the possible role of magnesium in attaining asthma control. This study is limited by the small sample size. A larger sample size would help draw more statistically accurate conclusion. Moreover, follow up with a direct observation of improvement in disease with increase in serum magnesium levels, would add further value to the aforementioned results.
The indings of this study is similar to that in the study conducted by Haury et al., who reported signi icantly lower level of serum magnesium in asthmatics compared to healthy subjects [6]. This is also in concordance to the indings of the studies conducted by Siebes KD et al., Mohammed NS et al., and Ahmed AA et al. [7][8][9]. Nevin et al., also concluded that the mean serum magnesium levels are lower like the current study [10]. However the study conducted by karkish KS et al., found no such co relation [11]. Other similar studies conducted on adults also report no signi icant co-relation [12,13].
Hence, this study shows that serum magnesium can be an indicator of asthma control and lower levels show poor controls. Further, the indings of the study can be used to study the role of magnesium supplementation therapy in long term treatment of asthma.

Conclusion
This study reveals that the serum magnesium levels even if in normal range are statistically lower amongst asthmatics. It also brings out the relationship between magnesium levels and lung function tests, showing an improvement in the latter with increase in the former.