Asthma burden and its impact on health-related quality of life among school adolescents in Anuradhapura district, Sri Lanka

Abstract

BACKGROUND

Asthma is a common chronic airway disease in adolescents, causing respiratory symptoms such as wheeze, shortness of breath, chest tightness, and cough. Asthma significantly impacts health-related quality of life (HRQoL). Its prevalence and symptom patterns in Southeast Asia, particularly among Sri Lankan adolescents, are not well known.

AIM

To assess the prevalence of asthma and its impact on the quality of life in Sri Lankan adolescents.

METHODS

A cross-sectional survey was conducted among 1099 adolescents aged 13-15 years in mixed-gender schools in the Anuradhapura district, Sri Lanka (46.4% boys, mean age 14.03 years). The International Study of Asthma and Allergies in Childhood questionnaire was used to assess asthma prevalence. Students with physician-diagnosed asthma and wheezing in the previous 12 months were categorized as having current asthma. The PedsQL inventory was used to assess HRQoL.

RESULTS

The prevalence of current asthma, physician-diagnosed asthma, and severe asthma was 13.8% [95% confidence interval (CI): 11.8-15.8], 20.2% (95%CI: 17.8-22.5), and 4.6% (95%CI: 3.4-5.8), respectively. Exercise-induced wheeze, sleep, and speech disturbances were significantly associated with asthma (P < 0.001). Overall, HRQoL was consistently reduced across all asthma diagnostic categories (current asthma, physician-diagnosed asthma, and severe asthma) compared with adolescents without asthma (P < 0.001).

CONCLUSION

There is a significant burden of asthma among adolescents, with 13.8% having current asthma and 4.6% having severe asthma. Adolescents with current asthma have reduced HRQoL compared to non-asthmatics, highlighting the need for comprehensive management strategies beyond symptom control.

Key Words: Adolescents; Asthma; Health-related quality of life; Quality of life; Wheeze

Core Tip: This population-based study among 1099 Sri Lankan adolescents revealed a substantial burden of asthma, with prevalences of current asthma, physician-diagnosed asthma, and severe asthma of 13.8%, 20.2%, and 4.6%, respectively. Wheezing during play or exercise, sleep disturbance, and speech disturbance were significantly more common among adolescents with asthma. Importantly, asthma was consistently associated with reduced health-related quality of life across all asthma diagnostic categories, highlighting its wider physical and psychosocial impact. These findings emphasize the need for early identification, regular monitoring, and comprehensive asthma management strategies that address not only symptom control but also the overall well-being of affected adolescents.

INTRODUCTION

Asthma is a chronic inflammatory disease of the airways characterized by airway hyper-responsiveness and airflow limitation[1]. The International Study of Asthma and Allergies in Childhood (ISAAC) demonstrated a high prevalence of asthma among adolescents across several regions worldwide, including Asia[2]. In Southeast Asia, the reported prevalence of asthma ranges from 29% to 32%[3]. The age-related burden of asthma, measured in disability-adjusted life years, peaks in the age ranges of 10-14 years and 75-79 years, while the lowest burden is seen in the 30-34 years age group[4]. A previous study conducted in Sri Lanka reported a 10.7% prevalence of asthma among school-aged adolescents[5]. According to the Global Initiative for Asthma, asthma is characterized by having respiratory symptoms such as wheeze, shortness of breath, chest tightness, and cough[1]. Wheeze is the cardinal symptom of asthma[6]. A systematic survey reported a prevalence of wheezing ranging from 13.2% to 13.7% among adolescents with asthma[2]. Several factors are associated with the development of asthma, including both environmental and genetic influences[5,7]. However, these factors alone do not fully explain the wide variation in asthma prevalence among populations with similar genetic backgrounds or environmental influences[8]. Therefore, it is important to assess the epidemiology of asthma to better understand its burden and determinants among adolescents, a group often overlooked in routine epidemiological surveys.

Asthma can significantly impair health-related quality of life (HRQoL) in adolescents, affecting sleep, speech, and overall well-being[7,9]. Recurrent respiratory symptoms, activity limitations, sleep disturbances, and the need for long-term treatment can significantly affect adolescents’ overall HRQoL. As a result, assessing HRQoL has become an integral part of asthma evaluation, providing valuable insights into the disease burden that are not captured by clinical measurements alone. Therefore, this study aimed to determine the prevalence of asthma among adolescents and evaluate its impact on their HRQoL.

MATERIALS AND METHODS

Study design, setting, and participants

A cross-sectional study was conducted among 13- to 15-year-old adolescents in Sinhala-medium mixed-gender schools in the Anuradhapura district, Sri Lanka.

Sample size and sampling technique

The minimum sample size (n) required to determine the prevalence of asthma was calculated using the following formula: n = Z²_{(1- α/2)} P (1-P)/d².

The expected prevalence of asthma among adolescents was estimated at 15%[5]. A 95% confidence level (Z = 1.96) and 5% precision were used: n = 1.96² × 15 (100-15)/5² = 195.92, ≈ 196.

A design effect of 2.5 was applied to account for multistage sampling. With an average class size of 31, the sample size was 465. After adding a 10% nonresponse adjustment, the final sample size was 544 adolescents.

A multistage sampling technique was used to select the study population. Mixed-gender schools of Type 1AB, Type 1C, and Type 2 in the Anuradhapura district were considered. Two schools from each type were randomly selected, representing all five educational zones. From each selected school, six classes (two from Grades 8, 9, and 10) were randomly chosen, and all students present were included. Children with learning and physical disabilities were excluded.

Data collection

The school administration was informed prior to the distribution of the questionnaire, and approval was obtained from the school principal and the director of the provincial educational department in Anuradhapura. A group of research assistants with medical backgrounds (MBBS graduates) was present, and they provided explanations as participants completed the questionnaire. In this survey, physical examination was not performed on the children.

Study instruments: Data were collected using a three-part, self-administered, validated questionnaire. Part I includes socio-demographic and family characteristics, while Part II evaluates asthma prevalence using the validated ISAAC questionnaire[10]. It has been used worldwide in many studies across different languages[11]. The questionnaire had been translated, pretested, and used in prior Sri Lankan studies[7,12,13].

Part III was the Pediatric Quality of Life Inventory (PedsQL 4.0, self-report form for teens - Generic Core Scales), which assessed the quality of life of affected adolescents[14,15]. This questionnaire had been previously translated into the main local language (Sinhala), had undergone linguistic validation by Mapi Research Trust, and had been used in previous Sri Lankan studies[9].

Identification of adolescents with asthma: The prevalence of asthma was estimated using the ISAAC tool[10]. In accordance with ISAAC, participants who reported wheezing during the past 12 months were identified as having current wheezing (CW). Participants who had been diagnosed with asthma by a physician and had wheezing in the previous 12 months were categorized as having current asthma (CA). Symptoms of severe asthma (SA) are defined as current wheeze in the past 12 months, 4 or more wheeze attacks, or > 1 night per week of sleep disturbance from wheeze. Reported ‘‘Physician-diagnosed asthma’’ (PDA) was defined from the question ‘‘Have you ever had asthma?”.

Computation of total HRQoL: The Pediatric Quality of Life Inventory (PedsQL 4.0, selfreport form for teens) assessed 23 items across four domains: Physical, emotional, social, and school functioning. A 5-point response scale was used (0 = never a problem; 1 = almost never a problem; 2 = sometimes a problem; 3 = often a problem; 4 = almost always a problem). Items were reverse-scored and linearly transformed to a 0-100 scale (0 = 100, 1 = 75, 2 = 50, 3 = 25, 4 = 0). Total HRQoL scores were computed out of 100, with higher scores indicating better HRQoL[14].

Statistical analysis

Asthma prevalence was calculated as the proportion of asthmatic children among all participants. Binary logistic regression identified socio-demographic correlates and compared respiratory symptoms between asthmatics and non-asthmatics, adjusting for age and sex, while non-parametric tests compared HRQoL scores between the groups. A P value < 0.05 was considered significant.

RESULTS

A total of 1113 questionnaires were distributed, and all of them were returned. Of them, 1099 (98.9%) properly filled questionnaires were included in the final analysis. The study population consisted of 510 boys (46.4%), with a mean age of 14.03 years (range 13-15 years, standard deviation 0.8 years).

The prevalence of asthma and its socio-demographic correlates

The prevalence of CA, PDA, and SA among school adolescents was 13.8% [95% confidence interval (CI): 11.8-15.8], 20.2% (95%CI: 17.8-22.5), and 4.6% (95%CI: 3.4-5.8), respectively (Table 1). CA (14.9%), PDA (21.2%), and SA (5.7%) were more prevalent among males, but this was not statistically significant. Table 2 shows socio-demographic correlates of asthma. Being the third child in the family [adjusted odds ratio (OR) 0.41, 95%CI: 0.19-0.88, P = 0.02, logistic regression adjusted for age and sex] and being a member of a family with 4 or more children (adjusted OR 0.33, 95%CI: 0.13-0.80, P = 0.01, logistic regression adjusted for age and sex) was associated with a significantly lower risk of asthma.

Table 1 Prevalence of asthma, according to gender distribution, n (%).

Asthma categories	Male (n = 510)	Female (n = 589)	Total (n = 1099)	Adjusted OR (95%CI)	P value1
Current asthma	76 (14.9)	76 (12.9)	152 (13.8)	0.84 (0.60-1.19)	0.3
Current wheeze	128 (25.1)	127 (21.6)	255 (23.2)	0.82 (0.62-1.1)	0.1
Physician- diagnosed asthma	108 (21.2)	114 (19.4)	222 (20.2)	0.89 (0.66-1.20)	0.4
Severe asthma	29 (5.7)	22 (3.7)	51 (4.6)	0.64 (0.36-1.13)	0.1

¹Logistic regression analysis. CI: Confidence interval; OR: Odds ratio.

Table 2 Socio-demographic factors associated with current asthma, n (%).

Variable	Category	Current asthma (n = 152)	Non asthmatics (n = 947)	Adjusted OR (95%CI)	P value1
Sex	Male	76 (50.0)	434 (45.8)
	Female	76 (50.0)	513 (54.2)	0.8 (0.6-1.1)	0.3
Family size	Only child	16 (10.5)	60 (6.3)
	2-3 children	127 (83.6)	785 (82.9)	0.6 (0.3-1.0)	0.08
	4 or more children	9 (5.9)	102 (10.8)	0.3 (0.1-0.8)	0.01
Birth order	Eldest	86 (56.6)	486 (51.3)
	2nd child	55 (36.2)	328 (34.6)	0.9 (0.6-1.3)	0.7
	3rd child	8 (5.3)	109 (11.5)	0.4 (0.1-0.8)	0.02
	4th child or more	3 (2.0)	24 (2.5)	0.7 (0.2-2.4)	0.6
Maternal employment	Employed	25 (16.4)	163 (17.2)
	Unemployed	127 (83.6)	784 (82.8)	1.0 (0.6-1.6)	0.7
Father’s employment	Employed	147 (97.4)	910 (97.7)
	Unemployed	4 (2.6)	21 (2.3)	1.2 (0.4-3.5)	0.7
	No response	1	16

¹Logistic regression analysis. Non asthmatics: Criteria for current asthma not fulfilled; CI: Confidence interval; OR: Odds ratio.

Symptomatology of current asthma

Table 3 demonstrates the symptomatology of CA. 59% of adolescents with CA reported a dry cough at night, while 32% of asthmatics had 4 or more wheezing episodes in the past 12 months. One-third of the population had wheezing during play/exercise. Furthermore, wheezing during play/exercise was significantly more prevalent among adolescents with asthma (73%) than among non-asthmatics (25%; P < 0.001). Sleep disturbance (8%) and speech disturbance (17%) were significantly associated with asthma (P < 0.001).

Table 3 Symptoms associated with current asthma, n (%).

Symptoms during the past 12 months	Prevalence among current asthmatics (n = 152)	Prevalence among non-asthmatics (n = 947)	Adjusted OR (95%CI)	P value1
Dry cough at night	89 (58.6)	223 (23.5)	4.74 (3.31-6.79)	< 0.001
Wheezing (4 or more episodes)	48 (31.6)	24 (2.5)	17.88 (10.45-30.57)	< 0.001
Exercise-induced wheeze	111 (73.0)	245 (25.9)	7.98 (5.41-11.78)	< 0.001
Speech disturbance	26 (17.1)	14 (1.5)	13.97 (7.09-27.53)	< 0.001
Sleep disturbance (one or more nights per week)	12 (7.9)	4 (0.4)	20.41 (6.46-64.46)	< 0.001

¹Logistic regression analysis. Non asthmatics: Criteria for current asthma not fulfilled; CI: Confidence interval; OR: Odds ratio.

HRQoL in adolescents with asthma

The mean HRQoL scores were noted as 79.09 in adolescents with CA, 78.82 in CW, 79.67 in PDA, and 77.27 in SA (Figure 1). Overall, the HRQoL score was consistently lower across all asthma diagnostic categories (CA, CW, PDA & SA) compared with that of adolescents without asthma (P < 0.001).

Figure 1 Health-related quality of life in adolescents according to different diagnostic criteria for asthma and wheezing. 95%CI and P values were calculated for the mean difference; Unpaired t-test. CI: Confidence interval.

DISCUSSION

The study population consisted of over 1000 adolescents aged 13-15 years, of whom 46% were male. The prevalence of CA, PDA, and SA were 13.8%, 20.2%, and 4.6%, respectively. The presence of asthma was not significantly associated with gender, but with birth order, as being the third child in the family of asthma and family size; 4 or more children in the family were associated with a reduced risk. Seventy-three percent of adolescents with asthma complained of wheezing during play/exercise, which was significantly higher in adolescents with CA. Sleep disturbance and speech disturbance were significantly associated with asthma compared to non-asthmatics. Overall, HRQoL scores were consistently lower across all asthma-related categories (CA, CW, PDA, and SA) than in adolescents without asthma.

In this study, the prevalence of PDA exceeded that of CA and SA, indicating that while many adolescents had received a diagnosis of asthma at some point, only a smaller proportion had active disease at the time of the survey, and an even smaller subgroup experienced severe asthma. Comparable findings were observed in a cross-sectional study conducted among adolescents aged 12-14 years in a district of Sri Lanka, which reported a prevalence of 10.7% for current asthma and 14.5% for physician-diagnosed asthma[5]. Another study conducted among adolescents aged 13-14 years in the Anuradhapura municipal council area reported that the prevalence of physician-diagnosed asthma and severe asthma was 19.0% and 15.3%, respectively[3]. Although these findings are broadly comparable, variations in prevalence across studies are evident. These differences may largely reflect variations in geographical coverage and participant characteristics. The previous study conducted in Anuradhapura was restricted to a single municipal council area representing a predominantly urban population[3], whereas the present study was conducted across the entire Anuradhapura district using a district-wide multistage sampling strategy that included a representative sample of adolescents from both urban and rural schools. Consequently, the current study provides a wider representation of adolescents in the district and may better capture geographical variation in asthma burden. In addition, differences in age range, sampling strategies, environmental exposures, socioeconomic characteristics, healthcare access, and diagnostic practices may have contributed to the observed variation in prevalence across studies. Comparable patterns have also been reported internationally. A study conducted in Taiwan among adolescents aged 13-14 years reported a higher prevalence of physician-diagnosed asthma (12.4%) than of current wheeze (9.2%) and severe asthma (3.3%)[16]. These variations in prevalence may reflect differences in study settings, population characteristics, environmental exposures, or definitions and instruments used to identify asthma.

In this study, asthma prevalence did not significantly differ between males and females. In contrast, a study conducted among adolescents aged 12-14 years in Sri Lanka showed a significant difference in the prevalence of asthma between genders, with a higher prevalence among males[5]. Similar to our results, a study conducted among school adolescents aged 12-16 years in India reported no significant gender difference in the prevalence of asthma[17]. These variations may be explained by the heterogeneous nature of asthma, which varies by age, sex, genetic and epigenetic factors, and environmental exposures[18]. Generally, boys tend to have a higher prevalence of asthma during childhood, while adult women show increased prevalence and severity, likely influenced by fluctuations in sex hormone levels during puberty, the menstrual cycle, and pregnancy[18].

The current study reported birth order; being the third child in the family was significantly associated with a reduced risk of asthma. Furthermore, the risk of asthma was inversely associated with larger family size. Similarly, a study conducted in Israel reported an inverse relationship between family size and asthma prevalence, suggesting that children from larger families have a lower risk of developing asthma[19]. This observation could be explained by the hygiene hypothesis, which proposes that greater exposure to infectious agents and microbial diversity promotes immune maturation and reduces the likelihood of allergic diseases, including asthma[19]. There may be differences in early-life environmental exposures among children of different birth orders. Later-born children may have greater exposure to microorganisms through increased contact with older siblings, potentially influencing immune-system maturation and promoting immune tolerance. In agreement, another study from Sri Lanka has reported that the first child of the family was significantly more likely to have current asthma[5].

In the current study, 73% of adolescents with asthma reported wheezing during play/exercise. The finding is consistent with a study conducted in Sri Lanka, which reported that more than half of adolescents with asthma complained of wheeze during exercise. Furthermore, several studies have shown a higher burden of exercise-induced wheezing among asthmatics[20,21]. These studies support the well-established concept of exercise-induced bronchoconstriction, which is particularly common among individuals with asthma. Interestingly, in the present study, one-third of the population experienced wheeze during play/exercise, which may be attributable to the dusty environment in the dry zone; however, this warrants further investigation.

The current study reported that sleep disturbance and speech disturbance were significantly more common among adolescents with asthma compared to non-asthmatic adolescents. This finding aligns with a study conducted in the Western Province of Sri Lanka, which reported that sleep and speech disturbance were more prevalent among children and adolescents with asthma[7]. Moreover, several previous studies reported that adolescents with asthma experienced significantly higher sleep disturbance than those without asthma, and also exhibited significantly reduced memory tasks of delayed recall than adolescents without asthma[22,23]. These findings highlight that asthma affects not only respiratory health but also sleep quality, communication ability, and potentially psychological well-being among adolescents.

The findings of this study indicate that asthma has a broad and significant negative impact on adolescents’ quality of life. The consistently lower HRQoL scores across all asthma diagnostic categories (CA, CW, PDA, and SA) compared with adolescents without asthma suggest that asthma affects multiple aspects of daily functioning, including symptoms, activity limitations, and overall well-being. A study conducted in Sri Lanka among adolescents aged 12-14 years reported that adolescents with asthma had significantly impaired quality of life compared with healthy students[9]. Further, studies conducted worldwide among adolescents reported that quality of life was significantly impaired among adolescents with asthma compared to healthy controls[24,25]. These findings suggest that asthma affects not only respiratory function but also substantially impacts the physical, psychological, and social domains of life. This emphasizes the importance of comprehensive asthma management strategies that address the psychosocial and functional well-being of adolescents.

This study has several strengths. The large sample size, multistage sampling techniques and using validated tools in data collection have increased the validity of the results. Furthermore, this study enrolled adolescents across the entire district, including both urban and rural areas, thereby increasing the generalizability of the findings. More importantly, understanding the prevalence of asthma, its associated factors, and its impact on quality of life is essential for identifying high-risk groups, planning evidence-based interventions, and guiding public health strategies. Assessing these aspects among adolescents can provide a comprehensive picture of the burden of asthma, help prioritize healthcare resources, and support the development of targeted prevention and management programs aimed at improving both clinical outcomes and overall well-being. The main limitation of this study is that spirometry and bronchodilator reversibility testing were not performed to confirm the diagnosis of asthma. Logistically, these procedures were not feasible in the school setting where the study was conducted, particularly given the large sample size. Therefore, asthma was diagnosed using the ISAAC questionnaire, which is a country-validated tool. Furthermore, clinical physical examinations were not performed, which may have limited the ability to identify asthma-related clinical signs. Additionally, potential environmental risk factors, including exposure to air pollution, which may influence the development and severity of asthma, were not assessed. A further limitation of this study is that stratified analyses comparing asthma prevalence between urban and rural adolescents were not performed. Although the survey included schools across the Anuradhapura district, information on participants’ residential urban or rural status was not collected. In the Sri Lankan educational system, many adolescents attend schools outside their area of residence, particularly those enrolled in national or popular schools located in urban centers. Consequently, classifying participants solely by schools’ location would have resulted in substantial misclassification bias, as school location may not accurately reflect students’ residential environments. Therefore, an urban-rural comparison was not considered methodologically appropriate in the present study.

CONCLUSION

There is a substantial burden of asthma among adolescents, with 13.8% having current asthma and 4.6% having severe asthma, as assessed using the ISAAC questionnaire. Adolescents with asthma experienced a significantly higher rate of exercise-induced wheezing, sleep and speech disturbances and had lower quality-of-life scores compared to non-asthmatics. These findings highlight that asthma affects not only physical health but also overall well-being, underscoring the need for comprehensive management strategies beyond symptom control.

ACKNOWLEDGEMENTS

The authors wish to thank the provincial director of education of North Central Province, as well as the principals and teachers of the selected schools in the Anuradhapura district, for their administrative support.