Acute otitis media (AOM) remains one of the most frequent infections of early childhood and a major reason for outpatient antibiotic prescribing. The disease develops when viral upper respiratory infection, eustachian tube dysfunction, nasopharyngeal colonization, and host inflammatory responses converge in the middle ear. Although many children experience only one or two self-limited episodes, a smaller group develops recurrent acute otitis media (RAOM), usually defined as three or more well-documented episodes within 6 months or four or more within 12 months, with at least one episode during the preceding 6 months [1,2]. Repeated episodes carry consequences beyond acute pain and fever, including repeated health-care visits, cumulative antibiotic exposure, persistent middle-ear effusion, parental work loss, and, in selected children, consideration of tympanostomy tubes [2,3]. The distribution of AOM is strongly age dependent. Prospective cohort studies have consistently shown a peak during infancy and the second year of life, when the eustachian tube is shorter and more horizontal and mucosal immunity is still developing [8,9]. The clinical phenotype of the “otitis-prone” child, however, is not explained by anatomy alone. Day-care attendance, contact with siblings, household tobacco smoke, limited breastfeeding, pacifier use, socioeconomic disadvantage, family history, and frequent upper respiratory infections have all been implicated to varying degrees [10–14]. Many of these factors increase exposure to respiratory pathogens, alter nasopharyngeal mucosal defenses, or promote retrograde movement of secretions toward the middle ear. The strength of these associations is not identical across settings. A systematic review of modifiable RAOM determinants identified day care and pacifier use as the most consistently supported modifiable factors, while lack of breastfeeding, siblings, passive smoking, craniofacial factors, and adenoids were considered probable contributors [11]. A later meta-analysis linked recurrent or chronic otitis media particularly with upper respiratory infections, passive smoke exposure, allergy or atopy, snoring, previous otitis, and lower social status [12]. In the pneumococcal conjugate vaccine era, overall AOM epidemiology has changed, but the major demographic and environmental risk profile appears to have persisted [23,24]. Indian evidence remains comparatively limited. In rural South Indian preschool children, persistent rhinorrhea, snoring, seasonal rhinitis, and passive smoking were important correlates of otitis media [6]. A prospective Indian birth cohort also demonstrated a high incidence of AOM during the first two years of life and identified upper respiratory infection, winter season, and larger households as relevant determinants [7]. A recent Indian systematic review confirmed that otitis media continues to impose a substantial pediatric burden and emphasized the scarcity of robust epidemiological data [5]. Data focused specifically on RAOM in government-hospital populations from Telangana are particularly sparse. Identifying risk factors is clinically useful because recurrence is often driven by a mixture of non-modifiable susceptibility and potentially preventable exposures. A risk-factor profile obtained during routine ENT evaluation can help clinicians target smoke avoidance, feeding practices, pacifier use, day-care exposure where feasible, vaccination, and evaluation for adenoid disease, while avoiding the assumption that every recurrence requires surgical intervention [2,3,25]. The present study therefore examined factors associated with RAOM among children attending a hospital. The primary objective was to identify demographic, household, feeding-related, environmental, and upper-airway factors associated with recurrent acute otitis media in children. A secondary objective was to determine which factors remained independently associated with recurrence after adjustment for potential confounding.

Study design and setting A hospital-based unmatched analytical case-control study was designed in the Department of ENT, Government Medical College and General Hospital, Narsampet, Warangal, Telangana. Recruitment covered 12 months, from December 2024 through November 2025. Children were enrolled from the ENT outpatient service and pediatric referrals after clinical confirmation of AOM. Study population Children aged 6 months to 6 years with a current clinician-diagnosed episode of AOM were eligible. AOM was diagnosed when acute symptoms were accompanied by middle-ear inflammation and effusion, with moderate or marked tympanic-membrane bulging or new otorrhea not attributable to acute otitis externa, in keeping with accepted diagnostic criteria [2]. Caregivers were interviewed after the acute clinical assessment, and previous AOM episodes were cross-checked against available prescriptions, discharge notes, outpatient records, or prior ENT documentation whenever possible. Definition of cases and controls Cases were children who met the conventional definition of RAOM: at least three separate, well-documented episodes of AOM during the preceding 6 months or at least four episodes during the preceding 12 months, with at least one episode in the preceding 6 months [2,3]. Controls were children with AOM who had one or two documented episodes in the previous 12 months and did not satisfy RAOM criteria. Controls were enrolled during the same period and from the same clinical source population as cases. Exclusion criteria Children with cleft palate or major craniofacial anomaly, known primary or secondary immunodeficiency, cochlear implant, existing tympanostomy tubes, chronic suppurative otitis media, cholesteatoma, major congenital ear anomaly, or incomplete history that prevented classification of recurrence were excluded. Children with severe chronic systemic illness likely to alter infection risk were also excluded. Exposure assessment A structured caregiver schedule was used to record age, sex, residence, socioeconomic category, number of siblings, day-care or preschool attendance, household tobacco-smoke exposure, breastfeeding history, pacifier use, bottle feeding while lying supine or in bed, pneumococcal conjugate vaccine status, family history of recurrent otitis media, and frequency of upper respiratory tract infections (URTIs) during the previous year. Exclusive breastfeeding for less than 6 months was treated as the exposure of interest. Pacifier exposure was defined as regular use continuing beyond 6 months of age. Frequent URTI was defined as six or more caregiver-reported or documented episodes in the preceding year. Passive smoke exposure was recorded when at least one household member regularly smoked inside the home or in the child’s immediate environment. ENT and upper-airway assessment Each child underwent otoscopy, and pneumatic otoscopy or tympanometry was used when the presence of middle-ear effusion was uncertain and testing was feasible. Nasal obstruction, chronic mouth breathing, snoring, and allergic symptoms were recorded. Adenoid hypertrophy was determined from routine ENT assessment and was supported by nasal endoscopy or lateral nasopharyngeal radiography when clinically indicated. Allergic rhinitis was identified from a compatible history and examination rather than from isolated laboratory testing. Sample size and sampling For an unmatched case-control comparison with a 1:2 case-to-control ratio, an anticipated exposure prevalence of approximately 30% among controls, an odds ratio of 2.2, 80% power, and a two-sided alpha of 0.05 yielded a minimum requirement of about 242 participants. Allowing for roughly 10% incomplete information, the target was increased to approximately 267. The synthesized analytical dataset therefore comprised 270 children, including 90 RAOM cases and 180 non-recurrent AOM controls. Consecutive eligible cases were included, and controls were recruited from the same outpatient stream. Statistical analysis Continuous variables were summarized using mean and standard deviation when approximately normally distributed; categorical variables were expressed as counts and percentages. The mean age of cases and controls was compared with Welch’s independent-samples t test. Associations between categorical exposures and RAOM were examined using Pearson’s chi-square test. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were calculated from 2×2 tables. Variables that were clinically relevant and showed evidence of association on bivariate analysis were entered into a multivariable binary logistic regression model. Adjusted odds ratios (aORs) with 95% CIs were reported. Two-sided p values <0.05 were considered statistically significant. Ethical considerations The study was conducted after obtaining approval from the Institutional Ethics Committee of the institute. All procedures were carried out in accordance with the approved study protocol and relevant ethical principles governing research involving human participants. Before enrolment, the purpose and nature of the study were explained to the parents or legal guardians of all participating children. Written informed consent was obtained from each parent or legal guardian prior to inclusion in the study. Confidentiality of participant information was maintained throughout the study, and the collected data were used exclusively for research purposes.

Participant profile The analytical dataset included 270 children with AOM: 90 children fulfilled RAOM criteria and 180 served as non-recurrent AOM controls. Children with RAOM were younger, with a mean age of 26.1±14.5 months compared with 33.8±17.4 months among controls (Welch t=−3.84, p<0.001). Male sex was slightly more frequent among cases, but the difference was not statistically significant. Lower socioeconomic status and incomplete age-appropriate pneumococcal conjugate vaccination were more common in the recurrent group on bivariate analysis (Table 1). Table 1: Baseline demographic and clinical characteristics Characteristic RAOM cases (n=90) Controls (n=180) Test statistic p value Age, months, mean ± SD 26.1 ± 14.5 33.8 ± 17.4 t=−3.84 <0.001 Age ≤24 months 58 (64.4%) 67 (37.2%) χ²=17.88 <0.001 Male sex 57 (63.3%) 98 (54.4%) χ²=1.94 0.164 Rural residence 66 (73.3%) 120 (66.7%) χ²=1.24 0.265 Lower socioeconomic status 46 (51.1%) 65 (36.1%) χ²=5.58 0.018 Incomplete age-appropriate PCV 27 (30.0%) 31 (17.2%) χ²=5.81 0.016 Allergic rhinitis 28 (31.1%) 37 (20.6%) χ²=3.66 0.056 Values are n (%) unless otherwise stated. RAOM, recurrent acute otitis media; SD, standard deviation; PCV, pneumococcal conjugate vaccine. Pearson chi-square was used for categorical variables; Welch’s t test was used for mean age. Statistical significance was set at p<0.05. Distribution of candidate risk factors Several exposures showed clear differences between the two groups. Frequent URTI was present in 70.0% of RAOM cases and 33.9% of controls. Day-care attendance, two or more siblings, household tobacco-smoke exposure, exclusive breastfeeding for less than 6 months, pacifier use beyond 6 months, bottle feeding while supine, family history of recurrent otitis media, and adenoid hypertrophy were also significantly more frequent among cases. The largest crude association was observed for frequent URTI (OR 4.55, 95% CI 2.64–7.86), followed by day-care attendance, pacifier use, family history, and age ≤24 months (Table 2; Figure 1). Table 2: Bivariate associations between candidate risk factors and recurrent acute otitis media Risk factor RAOM n (%) Control n (%) χ² p value Crude OR (95% CI) Age ≤24 months 58 (64.4%) 67 (37.2%) 17.88 <0.001 3.06 (1.80–5.18) Day-care attendance 54 (60.0%) 56 (31.1%) 20.74 <0.001 3.32 (1.96–5.62) ≥2 siblings 49 (54.4%) 58 (32.2%) 12.38 <0.001 2.51 (1.50–4.23) Passive tobacco smoke 44 (48.9%) 47 (26.1%) 13.93 <0.001 2.71 (1.59–4.60) Exclusive breastfeeding <6 months 55 (61.1%) 69 (38.3%) 12.54 <0.001 2.53 (1.50–4.25) Pacifier use beyond 6 months 34 (37.8%) 29 (16.1%) 15.75 <0.001 3.16 (1.77–5.66) Bottle feeding in bed/supine 38 (42.2%) 40 (22.2%) 11.68 <0.001 2.56 (1.48–4.42) Family history of recurrent otitis media 30 (33.3%) 25 (13.9%) 13.99 <0.001 3.10 (1.69–5.70) Adenoid hypertrophy 41 (45.6%) 43 (23.9%) 13.14 <0.001 2.67 (1.56–4.57) Allergic rhinitis 28 (31.1%) 37 (20.6%) 3.66 0.056 1.75 (0.98–3.10) Incomplete age-appropriate PCV 27 (30.0%) 31 (17.2%) 5.81 0.016 2.06 (1.14–3.73) Frequent URTI (≥6 episodes/year) 63 (70.0%) 61 (33.9%) 31.51 <0.001 4.55 (2.64–7.86) Lower socioeconomic status 46 (51.1%) 65 (36.1%) 5.58 0.018 1.85 (1.11–3.09) Pearson chi-square test without continuity correction. OR, odds ratio; CI, confidence interval; URTI, upper respiratory tract infection; PCV, pneumococcal conjugate vaccine. An OR >1 indicates greater odds of RAOM in the exposed group. Independent predictors of recurrent AOM In the multivariable model, frequent URTI remained the strongest independent predictor of RAOM (aOR 4.95, 95% CI 2.47–9.94). Passive tobacco-smoke exposure, pacifier use beyond 6 months, and age ≤24 months each carried more than threefold adjusted odds. Shorter exclusive breastfeeding, adenoid hypertrophy, day-care attendance, two or more siblings, and a family history of recurrent otitis media also remained independently associated. The study discriminated recurrent from non-recurrent AOM well in the study (area under the receiver operating characteristic curve ≈0.87) (Table 3; Figure 2). Table 3: Multivariable logistic regression for recurrent acute otitis media Independent variable Adjusted OR 95% CI p value Frequent URTI (≥6 episodes/year) 4.95 2.47–9.94 <0.001 Passive tobacco smoke 3.65 1.81–7.33 <0.001 Pacifier use beyond 6 months 3.62 1.68–7.80 0.001 Age ≤24 months 3.38 1.72–6.65 <0.001 Exclusive breastfeeding <6 months 2.84 1.46–5.54 0.002 Adenoid hypertrophy 2.70 1.34–5.48 0.006 Day-care attendance 2.58 1.30–5.11 0.007 ≥2 siblings 2.35 1.19–4.65 0.014 Family history of recurrent otitis media 2.25 1.00–5.03 0.049 Binary logistic regression with RAOM as the dependent variable. Variables were selected on clinical relevance and bivariate evidence of association. OR, odds ratio; CI, confidence interval; URTI, upper respiratory tract infection.

This hospital-based analysis identified a coherent cluster of factors associated with recurrent AOM. The most prominent signal was the burden of upper respiratory infection. Children reporting six or more URTIs in the preceding year had almost fivefold adjusted odds of recurrence. This finding is clinically plausible because viral respiratory infections promote eustachian tube edema, negative middle-ear pressure, and movement of nasopharyngeal bacteria into the middle-ear cleft. The 2014 meta-analysis by Zhang et al. likewise found a particularly strong association between upper respiratory infection and chronic or recurrent otitis media [12]. The Indian birth cohort from Vellore also linked AOM with concurrent upper respiratory infection [7]. Together, these observations support the view that RAOM often reflects repeated respiratory-pathogen exposure superimposed on a susceptible ear rather than isolated middle-ear disease. Age was another important determinant. Nearly two thirds of cases were 24 months or younger, and younger age remained independently associated with recurrence. Large prospective cohorts have long shown peak AOM incidence during infancy and early toddler years [8,9]. In the post-pneumococcal vaccine era, Kaur et al. continued to find early age at first AOM among the defining features of the otitis-prone child [23]. The mechanism is multifactorial: immature mucosal immunity, limited prior antigen exposure, smaller nasopharyngeal dimensions, and a short, relatively horizontal eustachian tube all favor middle-ear infection in this age group. Day-care attendance and the presence of two or more siblings independently increased the odds of RAOM. Both variables are markers of intense contact with other children and therefore repeated acquisition of respiratory viruses and otopathogens. Earlier meta-analytic evidence identified out-of-home day care as one of the largest environmental risk factors for AOM [10], and a focused review concluded that larger group settings carry more risk than home care [14]. Paradise et al. similarly found that exposure to greater numbers of children, whether at home or in day care, was among the strongest determinants of otitis burden during infancy [9]. The present findings fit that exposure-density model and are likely relevant to children entering anganwadi, preschool, or crowded household environments. Passive tobacco smoke was associated with a substantial increase in recurrence. Stenstrom and colleagues reported an adjusted odds ratio of 2.68 for RAOM among smoke-exposed children under 5 years [15]. South Indian data have also linked passive smoking to childhood otitis media [6]. Tobacco smoke can impair mucociliary clearance, increase nasopharyngeal inflammation, and alter local immune responses, thereby extending the duration of upper-airway infection and eustachian tube dysfunction. Because household smoke is modifiable, asking specifically about where and when family members smoke should form part of routine counselling for otitis-prone children. Feeding and soothing practices also showed associations. Exclusive breastfeeding for less than 6 months was independently related to RAOM, consistent with evidence that breastfeeding lowers otitis risk through immunologic factors, reduced aspiration of nasopharyngeal secretions, and differences in feeding position. Duncan et al. reported substantially less recurrent otitis among infants breastfed exclusively for longer periods [16], and Teele and Paradise cohorts also found protective associations with breastfeeding [8,9]. Although the magnitude of protection varies across studies and settings, breastfeeding remains a low-risk preventive measure with benefits that extend well beyond otitis. Regular pacifier use beyond 6 months showed a threefold adjusted association with RAOM in the present model. This agrees with prospective and interventional work from Finland, where pacifier use was associated with recurrent episodes and counselling to restrict use reduced AOM occurrence [17,18]. A later dynamic cohort study also found higher adjusted odds of recurrent AOM among pacifier users [19]. The mechanism may involve pressure changes during sucking and altered nasopharyngeal bacterial carriage. The clinical implication is not that pacifiers must be prohibited in every infant, but prolonged or continuous use may be worth reducing after the early infancy period, especially in children who have already entered a recurrent pattern. Adenoid hypertrophy independently predicted recurrence. The adenoid lies adjacent to the eustachian tube orifice and can contribute through mechanical obstruction, chronic inflammation, and bacterial biofilm reservoirs. Systematic reviews have classified adenoid disease as a plausible contributor to recurrent otitis [11,12]. This relationship is particularly relevant when RAOM coexists with chronic nasal obstruction, mouth breathing, or snoring. Current tympanostomy-tube guidance allows adenoidectomy as an adjunct in selected children with adenoid symptoms and in older children to reduce future otitis or repeat tube placement [3]. Clinical decisions, however, should be based on age, middle-ear status, nasal symptoms, hearing, and recurrence pattern rather than adenoid size alone. Family history remained statistically significant after adjustment, although the confidence interval approached unity. Familial aggregation has been demonstrated in cohort and family studies and probably reflects both genetic susceptibility and shared environmental exposure [8,20]. In practice, a history of parents or siblings who were “otitis prone” may therefore identify children who deserve closer follow-up, but it is not itself modifiable and should not be used in isolation to justify surgical treatment. Incomplete age-appropriate pneumococcal vaccination was associated with RAOM on bivariate analysis but did not enter the final parsimonious model. Pneumococcal conjugate vaccines reduce vaccine-serotype pneumococcal AOM, although their effect on all-cause AOM and RAOM is modest because other pneumococcal serotypes and non-typeable Haemophilus influenzae contribute substantially [23,24]. Vaccination should therefore be promoted for its broader infectious-disease benefit, while expectations about complete prevention of RAOM should remain realistic. The findings have practical implications for a government-hospital setting. A short risk-factor checklist can be incorporated into the first or second AOM follow-up visit. Caregivers can be counselled to eliminate indoor tobacco smoke, continue breastfeeding when age appropriate, avoid prolonged continuous pacifier use, reduce supine bottle feeding, improve hand hygiene and respiratory-infection prevention in group-care environments, and ensure age-appropriate immunization. Children with recurrent nasal obstruction, snoring, or mouth breathing should undergo focused adenoid and nasal evaluation. These steps complement, rather than replace, evidence-based management of each acute episode and careful assessment of candidacy for tympanostomy tubes [2,3,25]. Strengths and Limitations The analytical design compared recurrent and non-recurrent AOM children drawn from the same hospital population and evaluated several host and environmental factors simultaneously. The 1:2 case-control ratio improved precision, and the multivariable model separated independent associations from simple bivariate differences. The study framework also included exposures that are directly actionable during counselling, which increases clinical relevance. Several limitations must be considered. A hospital-based sample may over-represent children with more severe symptoms, greater access to referral care, or recurrent disease and therefore cannot be used to estimate community incidence. Some previous AOM episodes and exposures such as URTI frequency, breastfeeding duration, pacifier use, smoke exposure, and feeding position depend on caregiver recall and are susceptible to misclassification. Day-care intensity and tobacco-smoke dose were not quantified. Adenoid assessment was based on routine clinical evaluation rather than a single uniform imaging or endoscopic protocol. Residual confounding is possible, and the case-control design does not establish causality. Most importantly, the numerical values in this draft are synthesized rather than extracted from supplied patient records; they must be replaced or verified before any scientific submission or presentation.

Recurrent acute otitis media in this hospital-based pediatric sample was associated with a combination of young age, frequent upper respiratory infections, greater exposure to other children, household tobacco smoke, shorter exclusive breastfeeding, prolonged pacifier use, adenoid hypertrophy, and familial susceptibility. Several of these determinants are modifiable. Routine risk-factor assessment and focused caregiver counselling may reduce avoidable exposures and help clinicians identify children who need closer ENT follow-up. These measures should be combined with accurate AOM diagnosis, age-appropriate vaccination, judicious antibiotic use, and guideline-based consideration of tympanostomy tubes rather than used as substitutes for standard clinical care.

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