Wheeze and risk: Unpacking the environmental and social factors in young children

INTRODUCTION

Wheezing in early childhood is a common concern in paediatric practice, with studies indicating that approximately one-third of children experience wheezing episodes by the age of three. There is a paucity of Indian studies on wheezing; however, a recent study reported an incidence of recurrent wheezing of 43% among children under 5 years of age.^[1] The underlying causes of wheezing are multifaceted and may include genetic, anatomical, immunological and environmental factors. Many children with early-life wheezing are at increased risk for developing persistent respiratory conditions such as asthma, although only a subset progresses to chronic wheeze, underscoring the need for effective identification of high-risk individuals.^[2]

According to the Global Initiative for Asthma 2025 guidelines, wheezing in children under 5 years of age is classified using the modified asthma predictive index into categories of low, moderate and high probability of developing asthma.^[3] Transient early wheezing is often associated with viral infections and resolves as the child ages and airways enlarge. Persistent wheezing, by contrast, is frequently linked with atopic predisposition and may progress to asthma or other chronic respiratory diseases.^[4] The interaction of environmental exposures, such as tobacco smoke, indoor air pollution and socio-economic status (SES), plays a critical role in the prevalence and severity of wheezing episodes.^[5]

In India, there is limited data on the clinic-social and environmental factors that contribute to wheezing among children under 5. Given the paucity of research on risk factors in the Indian context, this study aims to bridge this gap by exploring the environmental risk factors and clinic-social profile of under-5 wheezers admitted to a tertiary care centre.

MATERIAL AND METHODS

This retrospective case-control study was conducted at the Karnataka Medical College and Research Institute. Data were collected from September 2022 to August 2023.

The study included children aged <5 years. Cases were defined as children admitted for recurrent wheezing episodes, i.e., recurrent wheezing has been defined by the National Asthma Education and Prevention Program Expert Panel as more than three episodes of wheezing in the past year that lasted more than 1 day and affected sleep,^[6] while controls comprised children of the same age group who attended the clinic for routine immunisation during the study period and also with no prior history of wheezing.

RESULTS

Figure 1 depicts the study flow chart. Thirty-four children initially met the criteria for recurrent wheezing, but four were excluded due to chronic conditions. The mean age at presentation was 30 months (median - 29.5 months; interquartile range 23.5–36 months), and all cases in the study were found to be more than 6 months old. The male-to-female ratio was 1.5:1, with a male preponderance of 60% (n = 18) in the study group and 1.3:1, with a male preponderance of 56% (n = 17) in the control group, consistent with other studies indicating a higher incidence of wheezing among males.^[10,11] The most common clinical presentation among the cases was cough (100%) followed by hurried breathing (80%) and chest indrawing (80%).

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Figure 1:

Selection of cases for the study.

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DISCUSSION

The findings from this study emphasise the significance of socio-economic and nutritional factors in the aetiology of wheezing among children under 5. Low SES emerged as a strong predictor, underscoring the role of poverty-related exposures such as overcrowding, poor ventilation and increased risk of respiratory infections.^[12] Similar associations between low SES and respiratory morbidity have been documented in both high-income and low-middle-income countries.^[13]

Children from lower SES backgrounds often faced challenges such as poor indoor air quality, crowding and limited access to healthcare, all contributing to higher wheezing prevalence.^[14] In addition, malnutrition and anaemia are prevalent among low SES populations and can impair immune function, increasing vulnerability to respiratory infections.^[15]

Anaemia, a common condition in this demographic, further compounded the risk. Iron deficiency can weaken immune responses, making children more susceptible to respiratory infections that could exacerbate wheezing. Poor nutritional status in low SES households can contribute indirectly to recurrent wheezing by weakening the body’s defences against infections.^[16] Preventive measures, including nutritional support and addressing household-level environmental risks, could be beneficial in this population.

CONCLUSION

In conclusion, this study identifies low SES and anaemia as significant risk factors for recurrent wheezing in children under 5. The findings highlight the importance of addressing social determinants of health, including poverty and nutritional deficiencies, in mitigating respiratory issues in young children.