What do we already know?

Australian recommendations include stopping using bottles for children from 1 year old, as well as avoiding bottle feeding in bed. These concerns are related to children’s teeth being in contact with sugar from drinks in bottles. Naturally occurring sugar, like in milk or fruit juice, or added sugar, like sugar added to formula, can lead to tooth decay. It is also related to feeding used to encourage children to become sleepy and go to sleep – if children are not being fed in response to hunger, it can lead to overfeeding and the risk of unhealthy weight gain.

Other studies on this topic have focused on children outside of Australia. Australia has its own unique public health situation – for example, 89% of the population has access to fluoridated water, which helps prevent tooth decay.

What happens to child’s health when this advice isn’t followed?

We did we do?

We used data from the Healthy Smiles Healthy Kids study, which was a birth cohort that followed a group of babies in Sydney from birth. When these children were 2 years old and 3 years old, their mothers were asked if their child was being bottle fed to sleep at bed times or nap times. When these children were 3-4 years old, they had their teeth checked and height and weight measured by community dental health therapists.

We used statistical models to investigate the link between bottle feeding to sleep with the risk of children having tooth decay or having overweight. We also considered other factors that could influence dental hygiene and weight.

What did we learn?

We found that one in three children were bottle feeding to sleep at 2 years old. Those who were had nearly twice as likely to have overweight when they were 3-4 years old.

We found that one in five children were bottle feeding to sleep at 3 years old. Those who were had nearly twice as many teeth affected by tooth decay when they were 3-4 years old.

We found that a higher risk of tooth decay for children whose mothers were born overseas.

So what?

It is important to support parents to settle children to sleep without using feeding. Doing this can avoid the risk of tooth decay and unhealthy weight gain. Stopping bottles from 1 year of age and avoiding using bottles in bed can help avoid unhealthy habits, like encouraging children being fed to settle them to sleep.

This work shows the importance of children seeing dentists early on in life. The Australian Dental Association recommends that children see a dentist by their first birthday or when their first tooth comes through, whichever happens first. This helps set up a routine of dental check-ups for children, with dentists being able to provide information about keeping teeth healthy, and spotting and treating tooth decay early.

This work also shows the importance of parents seeing their primary health care provider, like their GP, child and family health nurse, or practice nurse, through early childhood. Primary health care providers are the best placed to monitor children’s growth, development and milestones, and provide advice on child growth, dental health and healthy eating.

Resources for parents on swapping bottles for cups and avoiding bottles in bed are available from parenting organisations, such as Karitane, Tresillian and Raising Children’s Network.

As children whose mothers were born overseas had a higher risk of tooth decay, resources of parents need to be suitable for culturally and linguistically diverse communities, such as using images, be in-language, or use simple English. It is also important that families newly arriving to Australia are able to access and become familiar with the Australian health system, such as the Child Dental Benefits Scheme, which covers basic dental services like check-ups.

This work is part of Heilok Cheng’s PhD, which aims to examine formula feeding and bottle feeding as overlapping risk factors that may lead to overweight, obesity and tooth decay in early childhood. Her next steps are work with parents and clinicians to understand their perspectives and experience around keeping children’s teeth and weight in the early years.

Read the full paper here. Cheng, H.; John, J.; Scott, J.; Denney-Wilson, E.; Do, L.; Bhole, S.; Baur, L.; Arora, A. 2025. Bottle feeding to sleep beyond 12 months is associated with higher risk of tooth decay and overweight in Australian children: Findings from the Healthy Smiles Healthy Kids cohort study. Australian and New Zealand Journal of Public Health. https://doi.org/10.1016/j.anzjph.2025.100224

Media releases from the Public Health Association of Australia and The University of Sydney can be found here and here.

Heilok spoke to ABC Health & Wellbeing about what this work means for families with young children, including the importance of settling them to sleep without using feeding, here.