Adding fluoride to water helps to reduce tooth decay among children and is unlikely to increase the risk of hip fractures among older people, a new study suggests.

Researchers examined the health of people living in areas of England which have differing concentrations of fluoride in their drinking water supply.

Fluoride is a naturally occurring mineral found in water in varying amounts, depending on where people live.

It can help to prevent tooth decay, which is why it is added to many toothpastes, while in some parts of the country it is added to the water supply through a process called fluoridation.

Experts from the Office for Health Improvement and Disparities (OHID) and the UK Health Security Agency (UKHSA) examined tooth decay in three and five year olds and hospital admissions to remove children’s rotting teeth.

They also looked at hospital admissions for hip fractures in people of any age – though these mostly occur in older adults – after a previous study suggested there could be a relationship between fluoride and hip breaks.

The researchers found that five year olds living in areas with higher fluoride concentrations in drinking water were less likely to experience tooth decay compared to those living in regions with low concentrations.

Children living in areas with high concentrations of fluoride in the drinking water were up to 63% less likely to need their teeth removed in hospital due to decay.

The benefit appeared to be most apparent in the most deprived parts of the country.

Meanwhile, researchers said “no convincing evidence was found of higher rates of hip fracture in areas with higher fluoride concentrations, or in areas with a fluoridation scheme in place”.

Around one in 10 people in England have fluoride added to their drinking water.

These schemes cover much of the North East, Midlands, North West, East and Yorkshire and the Humber.

The OHID hopes to further rollout water fluoridation, with the Health and Care Bill, which is currently passing through Parliament, set to make that easier.

John Newton from the OHID said: “This report supports the view, as recently underlined by the UK chief medical officers, that water fluoridation is an effective public health intervention for reducing the prevalence of tooth decay and improving dental health equality.”

Tony Fletcher from the UKHSA added: “The environmental epidemiology team in UKHSA conducted analyses of data across English districts with varying drinking water fluoride concentrations.

“The results support previous findings that higher levels of fluoride are associated with improved dental health outcomes.

“We found no new evidence to conclude there is a risk of general health harms at the water fluoride concentrations studied, which are all within UK regulatory limits.”

Health Secretary Sajid Javid said: “The evidence is clear: water fluoridation is a safe and effective measure to help improve our nation’s oral health.

“This report continues to highlight how fluoridation can help reduce cavities and tooth extractions among children, especially those in more deprived communities, helping us level up health across the country.

“Through our Health and Care Bill, we will aim to make it simpler to roll out water fluoridation in more areas.”