Adolescent health

Prevalence, symptomatology and factors associated with asthma in adolescents aged 13–14 years from rural Sri Lanka: an analytical cross-sectional study

Abstract

Background Asthma is the most common chronic disease affecting children. However, the epidemiology of asthma in adolescents from rural geographies is lacking.

Methods An analytical cross-sectional study was conducted in secondary schools located in the municipal council area of the rural district of Anuradhapura, Sri Lanka. Random sampling was used to select 32 grade 8 classes from 6 out of 9 schools. The prevalence and symptomatology of asthma were determined using the validated International Study of Asthma and Allergy in Childhood (ISAAC) questionnaire and asthma symptom control using the asthma control test (ACT) translated into Sinhalese.

Results The study sample consisted of 1029 participants aged 13–14 years, including 528 (51.3%) boys and 501 (48.7%) girls. The prevalence of wheeze ever, current wheeze and wheeze while playing was 32.6% (n=335), 23.7% (n=244) and 25.2% (n=259), respectively. The prevalence of parent-reported physician-diagnosed asthma was 19.0% (n=196; 95% CI 16.7 to 21.6). Severe asthma was reported by 157 (15.3%; 95% CI 13.1 to 17.6) adolescents. The independent factors associated with severe asthma were sleeping on a cloth laid on the floor instead of a bed (p<0.02, adjusted-OR 9.72; 95% CI 1.56 to 60.78), cooking using sawdust (p=0.04, adjusted-OR 8.71; 95% CI 1.10 to 68.69) eczema (p<0.01; adjusted-OR 7.39; 95% CI 3.34 to 16.39) and allergic rhinitis (p<0.01; adjusted-OR 5.50; 95% CI 3.80 to 7.98). While having a cemented floor in the house (p<0.04; adjusted-OR 0.68; 95% CI 0.47 to 0.99) was a protective factor. Poor control of asthma symptoms was detected in 29 (29.9%) adolescents which was associated with comorbid allergic rhinitis (p<0.01; unadjusted-OR 5.40; 95% CI 1.84 to 15.82).

Conclusion Almost one in four adolescents had current wheeze, and 15.3% had severe asthma. Severe asthma was independently associated with allergic rhinitis, eczema, cooking using sawdust as fuel and sleeping on a cloth on the floor instead of a bed. Poor symptom control was found in 29.9% of severe asthmatics which was associated with comorbid allergic rhinitis.

What is already known on this topic

  • Asthma is highly prevalent in children and adolescents.

What this study adds

  • The prevalence of severe asthma (15.3%) among adolescents from rural Sri Lanka is comparatively high.

  • Unique factors (cooking using sawdust as fuel and sleeping on a cloth laid on the floor instead of a mattress) were independently associated with severe asthma in rural populations.

How this study might affect research, practice or policy

  • Poor symptom control among asthmatics was significantly associated with comorbid allergic rhinitis necessitating targeted strategies to identify and treat allergic rhinitis.

Introduction

Asthma is a chronic inflammatory disease of the airways that affects over 300 million people worldwide and is the most prevalent chronic condition in children.1 2 Asthma manifests in varying degrees of severity ranging from mild to severe. The severe form of asthma accounts for a substantial proportion of the overall disease burden and half of the asthma-related costs.1 The International Study of Asthma and Allergies in Childhood (ISAAC) study revealed a rise in asthma symptoms in various regions globally, including Asia.3 Southeast Asian countries have been identified as having a prevalence of asthma ranging between 29% and 32%.4 Despite the higher prevalence of asthma symptoms in many high-income countries, severe asthma is more prevalent in low-income and middle-income countries.2 The lower prevalence of asthma in developing countries is probably attributable to underdiagnosis than a true low prevalence.5 Insufficient awareness of the symptoms of asthma, even in asthmatics with frequent episodes, poor health-seeking behaviour and inadequate diagnostic facilities for asthma may contribute to the underdiagnosis.6 In the absence of a cure, asthma management is based on achieving optimal control of asthma symptoms and minimising future risk of adverse outcomes.7 Asthma control is defined as the extent to which asthma symptoms have been reduced by treatment. It depends on the availability of appropriate healthcare, adherence to treatment, environmental conditions and socioeconomic factors.8 9 Uncontrolled asthma decreases the quality of life and adversely affects healthcare utilisation.10

Adolescence is a transition period with significant physical, emotional and social changes. Asthma and its management affect adolescents in specific ways different from children and adults.11 Adolescents have to balance their academic demands, relationships and the desire for autonomy within the context of illness management, and adolescents with asthma have a greater risk of having anxiety or depression compared with healthy peers.12

Asthma is one of the most identified illnesses among school students in Sri Lanka and it causes significant school absenteeism.13 Despite the challenges adolescents with asthma face, the epidemiology and the impact of asthma on adolescents are inadequately discussed in the Sri Lankan context. Therefore, this study was conducted to assess the prevalence, associated factors and symptomatology of asthma among 13–14 year-old adolescents from a town in rural Sri Lanka.

Methodology

A government secondary schools-based, cross-sectional study was conducted from January to April 2023 to assess the epidemiology of asthma among children aged 13–14 years from the municipal council area of Anuradhapura, Sri Lanka. Nine government secondary schools registered in the Department of Education of the North Central Province are in the Anuradhapura municipal council area. Thirty-two grade 8 classes from six schools were randomly selected using multistage sampling. A prevalence of 11.9%, a precision of 2% and a dropout rate of 10% were used for sample size calculation.14 Students from grade 8 classes were recruited until the minimum sample size of 932 was achieved. Ethical approval was obtained from the Ethics Review Committee, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka (ERC/2022/42), and administrative approval was obtained from the Provincial Department of Education of the North Central Province, Zonal Education office of Anuradhapura and principals of each school.

Participant information sheets, consent forms and assent forms in the native languages (Sinhalese and Tamil) were provided to the parent(s) or guardian(s) and informed written consent was obtained. Validated native language translations of the ISAAC questionnaire for 13–14 years of children were provided to assess the prevalence of asthma and associated factors.15 The standard definitions recommended by the steering committee of the ISAAC study were used.15 Wheeze ever was defined as a positive response to the question ‘Have you ever had wheezing or whistling in the chest at any time in the past’. The current wheeze was a positive response to the question ‘Have you ever had wheezing or whistling in the chest in the past 12 months’. Current asthma was defined as having a current wheeze in participants with self-reported physician-diagnosed asthma. Severe asthma was defined as having four or more wheezing episodes, wheezing affecting speech (recurrent wheeze) or sleep disturbance due to wheezing for one or more nights per week in the preceding year.16 In addition, demographic data and information on known household, dietary and environmental factors associated with asthma were collected. The χ2 test was used to determine the statistical significance (p less than 0.05) of factors associated with asthma. Factors associated with asthma with a p value less than 0.20 were included in a multivariate binary logistic regression to identify independently associated factors.

Asthma control was assessed in children with severe asthma using native-language translations (Sinhalese) of the asthma control test (ACT) questionnaire for children aged 12–14 years.17 An independent panel conducted forward translations to Sinhalese and back translations to English with each panel of experts including clinical and language experts. Another panel of experts rated and selected the best translations. The final translated items were decided on the consensus of the panels of experts and investigators according to the Sumathipala and Murray method (online supplemental information 1).18 ACT questionnaire was used to categorise children with poorly controlled (score of 19 or less) and well-controlled asthma.

Patient and public involvement

The conceptualisation of the research idea was based on the respiratory issues routinely encountered in clinical practice. Discussions were held with adolescents who were not part of the current study, school teachers and parents of adolescents before the implementation to improve the study and also to minimise the discomfort and burden of questionnaire filling.

Results

The study sample consisted of 1029 participants with 528 (51.3%) boys and 501 (48.7%) girls. The mean age was 13.2 years with 826 (80.3%) aged 13 years and 203 (19.7%) aged 14 years. Most of the study participants (931, 90.5%) were born in Anuradhapura district, Sri Lanka. The prevalence of wheeze ever and current wheeze was 32.6% (n=335) and 23.7% (n=244), respectively (table 1). Dry cough at night and wheezing during playing were reported by 345 (33.5%) and 259 (25.2%) adolescents, respectively. The prevalence of parent-reported physician-diagnosed asthma was 19.0% (n=196; 95% CI 16.7 to 21.6). Severe asthma was reported by 157 (15.3%; 95% CI 13.1 to 17.6) adolescents.

Table 1
|
Symptomatology of asthma in 13–14 year-old adolescents from Anuradhapura, Sri Lanka (n=1029)

The association of demographic factors, housing conditions, dietary habits and playing habits with severe asthma is shown in table 2. The independent factors associated with severe asthma were sleeping on cloth on the floor (p<0.02, adjusted OR 9.72; 95% CI 1.56 to 60.78) (n=4 out of 6), cooking using sawdust (p=0.04, adjusted OR 8.71; 95% CI 1.10 to 68.69) (n=3 out of 5), eczema (p<0.01; adjusted OR 7.39; 95% CI 3.34 to 16.39) (n=18 out of 33) and allergic rhinitis (p<0.01; adjusted OR 5.50; 95% CI 3.80 to 7.98) (n=91 out of 266). Having a cemented floor in the house (p<0.04; adjusted OR 0.68; 95% CI 0.47 to 0.99) was a protective factor. The most common roofing material used was asbestos sheets in this population (n=752, 74.7%). However, roofing was not associated with severe asthma (p>0.26). The frequent use of incense burners or mosquito coils inside the house was not associated with severe asthma (p>0.46).

Table 2
|
Factors associated with severe asthma among 13–14 year-old adolescents in Anuradhapura, Sri Lanka (n=1029)

The ACT was completed by 97 (61.8%) severe asthmatics (table 3). The mean asthma control score was 20.5 (±3.3), ranging from 13 to 25 (figure 1). Poor control of asthma symptoms was detected in 29 (29.9%) adolescents. Comorbid allergic rhinitis was associated with poor control of asthma symptoms (p<0.01; unadjusted OR 5.40; 95% CI 1.84 to 15.82). Other evaluated demographic, housing, domestic, activity and dietary factors were not significantly associated with poor control of asthma symptoms (p>0.05).

Table 3
|
Asthma control of 13–14 year-old adolescents from Anuradhapura, Sri Lanka (n=97)
Figure 1
Figure 1

Distribution of asthma control test total scores among 13–14 year-old adolescents with symptoms of severe asthma (n=97).

Discussion

This study found that almost one out of the four adolescents aged 13–14 years in the Anuradhapura municipal council area (23.7%) had current wheeze, and 15.3% had severe asthma. Severe asthma was independently associated with allergic rhinitis, eczema, cooking using sawdust as fuel and sleeping on a cloth instead of a mattress. Living in a house with a cemented floor was a protective factor. Poor asthma control was found in 29.9% of severe asthmatics with an independent association with comorbid allergic rhinitis.

The current wheeze prevalence reported in Kandy (15.3%) and Anuradhapura (14.9%) districts among 13–14 year-old adolescents was significantly lower (p<0.01) than the current study.19 The current study was conducted in schools located in the municipal council area which may be reflected in the higher prevalence of current wheeze. However, the prevalence of current wheeze and current asthma in the Gampaha district—the second most populous district in Sri Lanka consisting of highly urbanised, moderately urbanised and rural sections—were significantly lower than the present study (16.7% (p<0.001) and 10.7% (p=0.049), respectively).9 This significantly higher prevalence warrants further exploration of contributory factors. The Global Asthma Network Phase I study conducted in the urban areas of India including 25 887 adolescents aged 13–14 years reported a significantly lower prevalence of current wheeze (3.63%, p<0.001) and severe asthma prevalence (1.60%, p<0.001).20 Similarly, the self-reported physician-diagnosed asthma prevalence in the present study is significantly higher compared with the previously known prevalence in the Gampaha district (14.5%, p=0.002) and urban centres in India (2.32%, p<0.001). According to phase III of the ISAAC study conducted among 13–14 year-old adolescents, the global, Indian subcontinent and Sri Lankan prevalence of current wheeze were detected to be 13.7%, 6.4% and 23.0%, respectively.21 22 The 23.7% prevalence of current wheeze noted in this study was comparable with the national reports of the ISAAC study.

The well-known independent association of asthma with allergic rhinitis and eczema was also observed in this study. The other independently associated factors were cooking using sawdust as a fuel and sleeping on a cloth on the floor. There is ample evidence demonstrating the occupational hazard of exposure to sawdust.23 Therefore, adolescents exposed to sawdust used as a cooking fuel are more likely to develop severe asthma. The number of adolescents from households using sawdust for cooking is limited in the current study. This association should be further investigated in communities where using sawdust as a cooking fuel is a common practice. The association of sleeping on a cloth on the floor with allergic rhinitis was observed in preschool children from the Anuradhapura district.24 Sleeping on the floor increases the risk of exposure to dust and house dust mites, a known risk factor for asthma.25 However, the confounding effect of factors associated with poor economic conditions cannot be excluded. Having cemented flooring was a protective factor against severe asthma, probably attributable to the easily cleanable nature preventing dust accumulation.26

ACT is a widely used tool to assess asthma control and poor control of asthma was found in almost one-third of the adolescents with severe asthma (29.9%). A study conducted in Italy showed that 23.2% of asthmatic children and adolescents had uncontrolled asthma.27 The poor control of symptoms highlights the need to provide tailored care to adolescents with severe asthma to improve their symptom control and quality of life, especially in children with comorbid allergic rhinitis.7 Current guidelines advocate achieving well-controlled asthma to have less frequent and less severe exacerbations, minimal use of rescue therapy and a better quality of life.

Strengths and limitations

This study was conducted in a representative sample of 1029 adolescents aged 13–14 years with generalisable results. The study highlighted the high prevalence of wheezing and asthma in a rural district of Sri Lanka with minimal attention given to asthma. This study uncovered that almost one-third of the adolescents with severe asthma had poorly controlled symptoms necessitating better targeted healthcare and increased awareness. This study followed the extensively used ISAAC methodology for identifying asthma and its symptoms. However, spirometry was not conducted to confirm the diagnosis. This cross-sectional study only assessed the association of factors with asthma and not their causative effect. The current study did not assess the level and duration of exposure, and age at the initial exposure of domestic, dietary and pet allergens. Furthermore, the current study did not assess the control of symptoms in adolescents undergoing treatment.

Conclusion

This study showed that almost one out of the four adolescents (23.7%) in this population had current wheeze, and 15.3% had severe asthma. Severe asthma was independently associated with allergic rhinitis, eczema, cooking using sawdust as fuel and sleeping on a cloth instead of a mattress. Living in a house with a cemented floor was a protective factor. Poor asthma control was found in 29.9% of severe asthmatics with an independent association with comorbid allergic rhinitis.