Asthma is one of the most common chronic diseases in children and adults worldwide, and its incidence has increased steadily over recent decades. It affected around 262 million people globally in 2019, resulting in approximately 461,000 deaths, with the majority occurring in low- and middle-income countries due to underdiagnosis and inadequate treatment.1 In India, about 6% of children and 2% of adults suffer from asthma2. The condition is characterized by airway inflammation leading to narrowing of the air passages, causing recurrent episodes of cough, wheeze, shortness of breath, and chest tightness, often aggravated by triggers such as viral infections, dust, smoke, pollen, animal dander, and weather changes. Asthma is a multifactorial disease influenced by genetic, environmental, and nutritional factors3. Family history of asthma or allergies such as eczema and rhinitis increases susceptibility. Urbanization, exposure to air pollution, low birth weight, prematurity, and tobacco smoke also contribute to its prevalence.Pathophysiologically, asthma involves chronic airway inflammation with infiltration of inflammatory cells like eosinophils, mast cells, lymphocytes, and neutrophils.4 These cells release pro-inflammatory mediators that lead to bronchoconstriction, mucus hypersecretion, airway edema, and remodeling. A key mechanism underlying this inflammation is oxidative stress, which results from an imbalance between the production of reactive oxygen species (ROS) and the body’s antioxidant defense systems5. Increased oxidative stress leads to damage of airway epithelial cells, mitochondrial dysfunction, and activation of inflammatory pathways, further aggravating airway hyper-responsiveness. Antioxidant enzymes such as superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) play critical roles in neutralizing ROS, and their function depends on trace elements like zinc, copper, and selenium.Zinc, in particular, is an essential trace element that plays multiple physiological roles, including antioxidant, anti-inflammatory, and immune-modulatory functions6. It is a structural component of more than 100 enzymes and is essential for DNA synthesis, protein production, wound healing, and cell division. Zinc deficiency leads to impaired immune function, delayed growth, and increased susceptibility to infections and inflammatory diseases7. In the respiratory system, zinc maintains epithelial integrity, prevents apoptosis of airway cells, and reduces eosinophilic inflammation. Low dietary intake of zinc and other antioxidants has been associated with increased risk and severity of asthma. Studies show that children with asthma often have reduced serum zinc levels compared to healthy controls.8 This deficiency may contribute to the inflammatory response in asthma by promoting a shift from T-helper 1 (Th1) to T-helper 2 (Th2) immune responses, favoring the production of pro-inflammatory cytokines such as interleukin-4 and interleukin-5, which exacerbate allergic inflammation.Moreover, in inflammatory diseases like asthma, redistribution of zinc occurs from plasma to the liver, reducing its bioavailability for immune cells. Several observational studies suggest that diets rich in zinc, selenium, magnesium, vitamins C and A, and omega-3 fatty acids may lower asthma risk by enhancing antioxidant defense mechanisms9. Understanding this relationship can provide valuable insights into the role of micronutrients in asthma pathogenesis and management, highlighting the potential benefit of zinc supplementation in improving outcomes for asthmatic children.

AIM

To assess and compare serum zinc levels between asthmatic and non-asthmatic children aged 2–14 years.

This hospital-based observational study was conducted in the Department of Paediatrics Medicine, Sardar Patel Medical College and P.B.M. Hospital, Bikaner, from November 2020 to October 2021. The study included children aged 2–14 years attending OPD or admitted indoors who met inclusion criteria. The calculated sample size was 157 using the formula N = Z² × P × Q / D², with P = 0.18, Z = 1.96, and D = 0.06. Due to the COVID-19 pandemic, 100 children were enrolled, including 78 asthmatic and 22 non-asthmatic controls. Asthma was defined as per GINA guidelines (cough, shortness of breath, wheeze, and chest tightness). Children with previously diagnosed asthma were included. Those with congenital lung lesions, GERD, cardiac or chest diseases, severe systemic illness, PEM, vasculitis, UTI, or malignancies were excluded.

Table:1 Distribution according to age

The mean age of Asthmatic cases was 6.83 years with majority of cases was in age group 3-5 years (42.31%). The mean age of Non-Asthmatic control was 7.14years with majority in age group 6-10 years (50%).

Table 2:Distribution according to social status

Asthmatic cases 57.69% were from lower middle & Lower Class followed by 42.31% were from upper middle& Upper Class. Similarly, in non-asthmatic control 54.55% were from lower middle & Lower Class followed by 45.45% were from upper middle& Upper Class.

Table 3:Distribution according to personal history regarding allergic tendency

Here in asthmatic cases History of allergy in family contacts was present in 21.79%, Any drug intake in 21.79%, Exposure to smoking in 19.23%, and History regarding travel was 11.54%. Similarly, in non-asthmatic control History of allergy in family contacts was present in 18.18%,Any drug intake in 18.18%, Exposure to smoking in

9.09%, and History regarding travel was present in 9.09%.

Table 4:Distribution according to immunization history

In asthmatic cases Complete Immunization was present in 98.71% and incomplete immunization was present in 1.29%. Similarly, In non-asthmatic control Complete Immunization was present in 100%.

Table 5:distribution according to pulmonary index score

In asthmatic group 51.28% had mild pulmonary index score, 43.59% had moderate and 5.1% had severe pulmonary index score.

Figure 1:             PFT (>6-year age)

In asthmatic children above 6 years of age PFT was calculated.  Here, in the group of normal zinc level of mean Force vital capacity, Force Expiratory volume, Fev1/Fvc, and PEFR(%predicted) were 89.50, 92.28, 89.44 and 96.11. Similarly, in the group of abnormal zinc level mean Force vital capacity, Force Expiratory volume, Fev1/Fvc, and PEFR(%predicted) were103.75, 98.00, 90.50 and 92.25.

Table 6:correlation between serum zinc and age

Mean Serum Zinc in Asthmatic cases having age <5 years was 106.6433.91µg/dl, in age group 6-10 years it was 98.5032.27µg/dl, in age group 11-15 years it was 71.8049.30µg/dl. Mean serum zinc in control having age <5 years was 111.6339.71µg/dl, in age group 6-10 years it was 133.8278.57µg/dl, in age group 11-15 years it was 132.0072.83µg/dl. Statistically there was significant difference in age group of 11-14 years  (P-value <0.05).

Table:7 Distribution according to nutritional status with serum zinc level

In asthmatic cases mean serum zinc level of underweight was 10749.27µg/ml, in well nourished was 10948.08µg/dl and in overweight was 9835.55µg/dl. Similarly, in non-asthmatic cases mean serum zinc level of underweight was 10453.63µg/dl, in well nourished was 10748.20µg/dl and in overweight was1150µg/dl

Table 8:correlation between serum zinc and asthma severity

Mean serum zinc level of mild cases was 114.8349.28µg/dl and in moderate cases was 98.9434.39µg/dl and in severe cases was 99.0025.62µg/dl.

Table 9:correlation between serum zinc level and type of therapy used

Mean serum values were found to be lower in the group on continuous inhaled therapy (105.242.6µg/dl) as compared to the group on intermittent inhaled therapy (10742.88µg/dl).

Asthma is a chronic inflammatory airway disease marked by reversible obstruction and bronchial hyper-responsiveness. Trace elements like zinc play vital roles in inflammation and antioxidant defense. Zinc is a key component of antioxidant enzymes that neutralize harmful oxygen free radicals; its deficiency leads to oxidative stress, airway inflammation, and hyperreactivity. Reduced zinc disturbs oxidant–antioxidant balance, contributing to pulmonary damage. Zinc also modulates immune responses by maintaining the Th1/Th2 cell balance and promoting regulatory T-cell activity. Thus, zinc deficiency is linked to asthma pathogenesis, severity, and poor control, though studies show conflicting results.

In the present study the mean age of Asthmatic cases was 6.83 years with the majority of cases being in the age group 3-5 years (42.31%). The mean age of NonAsthmatic control was 7.14years with majority in age group 6-10 years (50%).

In our study asthmatic cases 57.69% were from lower middle & lower class followed by 42.31% were from upper middle& upper class. Similarly, in non-asthmatic control 54.55% were from lower middle & lower class followed by 45.45% from upper middle & upper class. According to a study of Xavier Basagaña ¹⁰Asthma prevalence was higher in lower socioeconomic groups.

In the present study here in asthmatic cases History of allergy in family contacts was present in 21.79%, Any drug intake in 21.79%, Exposure to smoking in 19.23%, and History regarding travel was present in 11.54%. Similarly, in non-asthmatic cases History of allergy in family contacts was present in 18.18%, Any drug intake in 18.18%, Exposure to smoking in 9.09%, and History regarding travel was present in 9.09%. Strachan and Cook¹¹ in their study found out the relation between parental smoking and childhood asthma, parental smoking lead to more wheezing attacks among children with already diagnosed asthma while non-atopic children had more episodes of wheezy bronchitis.

In the present study, among 78 asthmatic children, 77 (98.71%) had a complete immunization history, while only 1 child (1.29%) had incomplete immunization. In comparison, all 22 (100%) non-asthmatic children were completely immunized. This indicates a high rate of immunization coverage in both groups. The slight difference observed was not statistically significant. Overall, immunization compliance was excellent among both asthmatic and non-asthmatic children.

In the present study, out of 78 asthmatic children, 40 (51.28%) had mild asthma with a Pulmonary Index Score of less than 7. Moderate asthma (score 7–11) was observed in 34 children (43.59%). Only 4 children (5.13%) had severe asthma with a score of 12 or more. This shows that the majority of cases were mild to moderate in severity. Overall, mild asthma was the most common presentation among the study subjects.

In our study (table no 13) we found that mean serum Zinc level in asthmatic and nonasthmatic children was statistically significantly different in age group 6-10 years (Pvalue 0.0021) and in age group 11-14 years (P-value 0.0001). El-Kholy et al¹² at the Department of Pediatric diseases in Ain Shams University, Cairo, Egypt, it was concluded that Zinc play vital roles in protein synthesis and enzyme activity and serum levels of Zinc was lower in children with asthma than normal people.

In present study  mean serum Zinc level in asthmatic underweight cases was 10749.27 µg/dl, in well nourished was 10948.08µg/dl and in over weight was 9835.55µg/dl. Similarly, in non-asthmatic serum Zinc level of underweight cases was 10453.63 µg/dl, in well nourished was 10748.20 µg/dl and in overweight was 1150µg/dl. According to the study of Annabelle Bédard¹³ aside from the complex interrelations between diet, physical activity, body composition and asthma, nutritional factors may also interact with genetic, environmental, lifestyle and social factors. Obesity is now a well-known risk factor for asthma.

In the present study, the mean serum zinc level among mild asthmatics was 114.88 ± 49.28 µg/dl, while in moderate cases it was 98.94 ± 34.39 µg/dl. Severe asthmatics had a mean zinc level of 99 ± 25.62 µg/dl. A decreasing trend in serum zinc concentration was observed with increasing asthma severity. This suggests a possible association between lower zinc levels and greater disease severity.

In our study  the mean serum Zinc level in asthmatic children which was on Intermittent Inhaled group was107µg/dl and on the Continuous Inhaled group was 105.2µg/dl. All of the asthmatic school children were taking inhaled steroids.AbdulWahab et al¹⁴ found no significant association between Zinc levels and the dose of inhaled steroids.

Serum Zinc may play a major role in asthma control but in our study this was inconclusive However, further multicenter studies with greater sample sizes and adequate statistical power are required to prove the findings of the present study. Measurement of Zinc level could be recommended in asthmatic patient. Proper supplementation of Zinc can be useful in the management of asthmatic patients by increasing the effect of antioxidant defence system and thereby, decreasing the airway inflammation. However, further multicenter studies with greater number of patient are needed to warrant the result of this study.

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