Underweight and early childhood caries among young children in rural Cambodia: a pilot study

The study addresses whether early childhood caries (ECC) is associated with underweight among children aged 1–3 years in rural Cambodia—a critical weaning period marked by rapid growth, eruption of primary teeth, and development of oral functions. Cambodia has high rates of underweight in under-fives, particularly in rural areas, and very high ECC prevalence beginning in infancy. Prior research suggests links between severe dental caries and low weight, and highlights socioeconomic and feeding practice influences. The purpose of this study is to determine associations between underweight and oral health-related factors, especially ECC, in rural Cambodian toddlers, informing integrated nutrition and oral health interventions.

Background literature indicates that underweight peaks during the weaning period in low- and middle-income countries and is influenced by socioeconomic status and feeding practices. Cambodia reports substantial undernutrition and high ECC prevalence starting before age two, with limited treatment access. Studies in Asian settings have reported that severe dental caries in young children is associated with being underweight. Cambodian surveys have documented poor oral health, high ECC prevalence in preschoolers, and links to behavioral and sociodemographic factors. Integrative strategies between oral and general health have been recommended to address ECC in early childhood.

Design and setting: Cross-sectional study conducted May 2018–January 2019 in Steung Trang district, Kampong Cham province, Cambodia. Participants: Children aged 1–3 years with registered births in villages served by Khpob Ta Nguon Health Center. Permissions were obtained from local authorities; caregivers provided written informed consent. Exclusion criteria: children declining participation or with fewer than 8 erupted teeth. Final sample: n=200 (111 males, 89 females; mean age 27.00±9.41 months; median 26.5 months). Sample size calculation: N = Z^2 P(1−P)/d^2 with Z=1.96, P=0.25 (underweight prevalence among 3-year-olds), d=0.06, yielding ≈200. Measurements: Age and birth weight were obtained from birth records and maternal health handbooks. Low birth weight (LBW) defined as <2500 g. Current weight measured using a digital scale (TANITA BC-760) to 0.1 kg, plotted to WHO Child Growth Standards weight-for-age Z-scores. Underweight categories: moderately-underweight <−2SD; severely-underweight <−3SD. Nutritional status assessed via mid-upper arm circumference (MUAC) using UNICEF non-stretch tape; MUAC <12.5 cm indicated malnutrition. ECC assessment: One trained dentist performed visual exams under natural light with child in knee-to-knee position, following WHO Oral Health Surveys Basic Methods. Intra-examiner calibration on 20 subjects yielded kappa=0.87. Questionnaire: Trained local interviewers obtained socio-demographics, child-rearing, diet, and oral hygiene practices. Statistical analysis: Data entered in Excel and analyzed with SPSS v25. Normality checked with Shapiro–Wilk test. Chi-square (and Fisher’s exact where appropriate) tested associations between variables and weight status. Logistic regression identified predictors of underweight, entering variables with P<0.10 at baseline and adjusting for sex, age, and number of erupted primary teeth. Significance set at P<0.05. Ethics: Conducted per Declaration of Helsinki; approved by Niigata University Ethical Committee (2017-0187).

- Prevalence: Moderately-underweight 33.5%; severely-underweight 7.0% among 200 children aged 1–3 years. ECC prevalence 61.5% (all untreated). LBW prevalence 15.2%; MUAC <12.5 cm (malnutrition) 5.1%. - Age trend: Moderate underweight increased with age (43.1% at age 3; P<0.05). - Bivariate associations: LBW associated with both moderate (P<0.05) and severe underweight (P<0.001). MUAC <12.5 cm associated with moderate and severe underweight (both P<0.05). ECC associated with moderate underweight (39.8% vs 23.4%; P=0.016); higher severe underweight in ECC (9.8% vs 2.6%; P=0.054). Sugary beverages more than once weekly associated with moderate underweight (41.2% vs 22.2% in never; P=0.028). - Multivariable logistic regression (adjusted for sex, age, erupted teeth): • Moderate underweight predictors: LBW OR 2.57 (95% CI 1.03–6.40; P=0.043); MUAC ≤12.5 cm OR 4.71 (95% CI 1.08–20.62; P=0.04). ECC showed a non-significant trend OR 2.21 (95% CI 0.97–5.00; P=0.058). Higher sugary beverage intake showed a trend OR 2.15 (95% CI 0.91–5.01; P=0.082). • Severe underweight predictors: LBW OR 10.68 (95% CI 2.95–38.65; P<0.001); ECC OR 6.67 (95% CI 1.02–43.61; P=0.048). MUAC ≤12.5 cm showed a non-significant trend OR 5.41 (95% CI 0.87–33.76; P=0.071).

Findings indicate that underweight status increases during the weaning period and is associated with low birth weight, malnutrition (low MUAC), and ECC. The association of ECC with severe underweight suggests that untreated caries may contribute to poor nutritional intake through pain and infection, compounding growth deficits. The results align with literature from similar settings showing increased undernutrition during weaning and ties between severe dental caries and lower weight. Socioeconomic and maternal education factors prevalent in rural Cambodia likely contribute to higher LBW and undernutrition. Poor access to pediatric dental care and low implementation of early oral hygiene further exacerbate ECC burden. These findings support integrated early interventions combining nutrition, maternal education, age-appropriate weaning, and ECC prevention/treatment to improve growth and oral health outcomes.

Underweight and ECC were highly prevalent among 1–3-year-old children in rural Cambodia and increased with age. Low birth weight, malnutrition as indicated by MUAC, and ECC were predictors of underweight. Comprehensive, integrated health and nutrition programs beginning in the weaning period—incorporating maternal education, age-appropriate feeding, and early oral health prevention and care—are recommended. Future research should include longitudinal studies to clarify causal pathways between ECC and underweight and evaluate the effectiveness of integrated interventions.

- Selection bias: participants were children attending health check-ups; caregivers may have higher health awareness than the general population. - Small sample size from a single rural district limits generalizability. - Cross-sectional design precludes causal inference between ECC and underweight. - Potential unmeasured confounders (e.g., detailed dietary intake, infection burden, socioeconomic gradients) may influence associations.