Prolonged and night-time bottle-feeding in relation to early childhood caries: a systematic review.

PURPOSE: Early childhood caries (ECC) remains a major public health problem worldwide. Infant feeding practices, particularly bottle-feeding duration and nocturnal bottle use, have been implicated as potential risk factors; however, evidence regarding duration-specific effects remains inconsistent. The aim was to systematically evaluate whether prolonged bottle-feeding and nocturnal bottle use are associated with increased prevalence of ECC. METHODS: This systematic review followed PRISMA guidelines and was registered in PROSPERO (CRD420251186608). MEDLINE, Cochrane Central, ScienceDirect and Scopus were searched up to May 2026. Observational studies involving children ≤ 71 months that reported ECC outcomes (dmft/dmfs/dft/deft) in relation to bottle-feeding duration and/or night-time bottle use were included. Risk of bias was assessed using ROBINS-E, and certainty of evidence was evaluated using GRADE. RESULTS: Twelve studies (two prospective cohorts and ten cross-sectional; 6,955 children) were included. Bottle-feeding limited to the first year of life was not associated with increased caries severity. Continuation beyond 12 months was associated with a gradual increase in ECC, whilst bottle-feeding beyond 24 months showed a consistent and clinically relevant increase in caries severity. Nocturnal bottle-feeding further amplified risk, particularly beyond 24 months, with evidence of dose-response relationships. Overall certainty of evidence was low to very low, limited primarily by observational study design, heterogeneity in exposure definitions and residual confounding. CONCLUSIONS: Evidence suggests a duration-dependent association between prolonged bottle-feeding and ECC severity, particularly beyond 24 months and during night-time. These findings support current recommendations for timely cessation of bottle use and avoidance of night-time bottle-feeding to reduce ECC burden.