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.