Trends and determinants of acute respiratory infection symptoms among under-five children in Cambodia: Analysis of 2000 to 2014 Cambodia demographic and health surveys

**Background:** Acute respiratory infections (ARIs) are the leading cause of mortality and morbidity among children under 5 years worldwide, accounting for approximately 1.3 million deaths annually and 33% of under-5 deaths in developing countries. In Cambodia, reported ARI prevalence in children under 5 years was 20% in 2000 and declined to 6% in 2014. Despite this global burden, limited data existed evaluating trends and determinants of ARI symptoms among Cambodian children over time. This study aimed to describe trends in ARI symptoms among children aged 0–59 months using four waves of the Cambodia Demographic and Health Survey (CDHS) and to identify socio-demographic, behavioral, and environmental factors associated with ARI symptoms.

**Methods:** The study analyzed existing children's data from the 2000, 2005, 2010, and 2014 CDHS, which used a two-stage stratified cluster sampling design. Analysis was limited to children born in the five years preceding each survey who were alive and living in households at the time of interview. Data were pooled across the four survey years, yielding 29,171 children aged 0–59 months. ARI symptoms were defined as the occurrence of cough accompanied by short, rapid breathing in the two weeks preceding the survey. Independent variables included maternal age, education, employment, smoking status, child age, sex, birth order, birth weight, BCG vaccination, vitamin A intake, breastfeeding, place of delivery, place of residence, household wealth quintile, source of drinking water, toilet facility type, and survey year. All analyses were performed using STATA version 16 with survey weights accounting for the complex survey design. Bivariate chi-square tests were used to assess associations, and multiple logistic regression was used to determine independent predictors of ARI symptoms, reported as adjusted odds ratios (AOR) with 95% confidence intervals (CI).

**Key Results:** The prevalence of ARI symptoms in the previous two weeks among children aged 0–59 months declined significantly from 19.9% [95% CI: 18.4–21.5] in 2000 to 8.6% [95% CI: 7.7–9.6] in 2005, 6.4% [95% CI: 5.6–7.4] in 2010, and 5.5% [95% CI: 4.8–6.3] in 2014 (p < 0.001). Factors independently associated with increased odds of ARI symptoms included: child age 6–11 months [AOR = 1.91; 95% CI: 1.53–2.38], 12–23 months [AOR = 1.79; 95% CI: 1.46–2.20], and 24–35 months [AOR = 1.41; 95% CI: 1.13–1.76] compared to children aged 0–5 months; maternal smoking [AOR = 1.61; 95% CI: 1.27–2.05]; and using non-improved toilet facilities [AOR = 1.20; 95% CI: 0.99–1.46; p = 0.064]. Factors associated with decreased odds of ARI symptoms included: mothers with higher education [AOR = 0.45; 95% CI: 0.21–0.94], breastfeeding [AOR = 0.87; 95% CI: 0.77–0.98], children in the richest wealth quintile [AOR = 0.73; 95% CI: 0.56–0.95], and later survey years (2005 [AOR = 0.36; 95% CI: 0.31–0.42], 2010 [AOR = 0.27; 95% CI: 0.22–0.33], 2014 [AOR = 0.24; 95% CI: 0.19–0.30]).

**Clinical Implications:** The substantial decline in ARI symptom prevalence from 19.9% in 2000 to 5.5% in 2014 represents a significant public health achievement for Cambodia, likely attributable to improved immunization coverage (including introduction of pentavalent vaccine in 2006 and BCG vaccination increasing from 40% in 2000 to 96% in 2014), socioeconomic development, and improved access to healthcare. The study identifies modifiable risk factors that should be targeted by interventions: maternal smoking cessation programs, promotion of breastfeeding, improved sanitation facilities, and maternal education. Children aged 6–35 months represent a particularly vulnerable group requiring focused attention. The findings support the need for government and child family programs to promote maternal education and infant breastfeeding. However, the study acknowledges limitations including the cross-sectional design preventing assessment of temporal associations, reliance on self-reported ARI symptoms introducing potential recall bias, and the data being from 2000–2014 which may not reflect the current situation. The authors recommend further evaluation using CDHS 2020–21 data when available.