People are being encouraged to keep their waist measurement to less than half their height to reduce the risk of potential health problems, according to recommendations in an updated NICE draft guideline.
For the first time, this update encourages adults with a body mass index (BMI) below 35 kg/m² (obesity class 2) to measure their own waist-to-height ratio.
Using the waist-to-height ratio, in conjunction with BMI, can help to provide a practical estimate of central adiposity, which is the accumulation of fat around the abdomen, to help to assess and predict health risks, such as type 2 diabetes, hypertension or cardiovascular disease.
NICE added the waist-to-height ratio to its draft guideline after looking at evidence from several studies which showed that, alongside BMI, it could be used to assess and predict weight-related conditions in all ethnicities and sexes.
The 2019 Health Survey for England estimated the prevalence of obesity in adults in England to be 28%, with overweight affecting a further 36%. Government estimates indicate that the current costs of obesity in the UK are £6.1 billion to the NHS and £27 billion to wider society.
The guideline also recommends, in line with international guidance, using lower BMI thresholds for overweight and obesity for people from South Asian, Chinese, other Asian, Middle Eastern, Black African, or African-Caribbean family compared to the general population.
This approach is already widely used because research shows people from some Black, Asian and minority ethnic groups are more prone to central adiposity and have an increased cardiometabolic health risk at lower BMI thresholds.
The guideline highlights the importance of healthcare professionals asking permission before any discussions with people that are linked to being overweight, obese or central adiposity, and to ensure they do so in a sensitive and positive manner.
Dr Paul Chrisp, director for centre for guidelines at NICE, said: “Our updated draft guideline offers people a simple and effective way of measuring their weight so they can understand the factors that could impact on their health and take action to address them.
“Our committee found that a clear benefit of using the waist-to-height ratio is that people can easily measure it themselves, interpret the results, and seek medical advice if they are at increased health risk.
“The evidence shows that people from some Black, Asian and minority ethnic groups have a greater propensity to develop central adiposity and have an increased cardiometabolic health risk so we have lowered the BMI thresholds for those communities, in line with international guidance, to ensure people from those family backgrounds can get support from weight management services if required.
“We are now looking for views from the healthcare professionals and the public on the proposed recommendations in the guideline before final publication.”
Guideline committee member Professor Rachel Batterham, consultant in obesity, diabetes and endocrinology, said: “Increased fat in the abdomen increases a person’s risk of developing several life-limiting diseases including type 2 diabetes and heart disease. Waist-to-height ratio is a simple, easy to use measure that identifies people who are at increased health risk and would benefit from weight management support to improve their health.”
Another guideline committee member, Dr Nivedita Aswani, consultant paediatrician specialising in diabetes and weight management at Sheffield Children’s Hospital, said: “We know that increased fat in the abdomen increases the risk of conditions such as type 2 diabetes, non-alcoholic fatty liver, hypertension and cardiovascular disease, even in young children.
“A waist measurement can be taken independently by a young person in the security of their own home, or by a carer for their child. A waist measurement of more than half of a person's height, is an indication of greater risk. Young people should be encouraged to seek advice about weight management, and sensitively supported to lower their risk of developing these conditions, and to improve overall health and wellbeing.”
The guideline has a number of further recommendations for research, including gathering additional information to assess health risks in adults and children and young people.
A consultation on the proposed recommendations is now taking place until Wednesday, 11 May 2022. People can have their say via nice.org.uk.