How long is A Piece of String? Less than Half your Height. Five Steps from Science to Screening: A Mini Review

Abstract

Central obesity is harmful in terms of cardiometabolic risk, but it can only be measured accurately with expensive equipment. The aim of this review is to summarise how the scientific evidence has accumulated to the extent that waist-to-height ratio (WHtR), which has been shown to be a simple proxy for central obesity, is starting to be adopted into public health policy and can now be used as a simple, early screening tool. A boundary value of WHtR 0.5 has been suggested as the first level of risk. This translates into the simple message "Keep your waist to less than half your height". However, to check if WHtR is less than 0.5 does not even need a tape measure. A piece of string will suffice. The string is used to measure the person's height and then it is folded in half to see whether it fits easily around the person's waist. If it does not, early health risk is indicated and further screening is indicated. Thus the string acts as a simple, cheap, signposting tool for early health risk. At long last we have the answer to that age old question: "How long is piece of string?" The answer is "Less than half a person's height if we want to improve public health through opportunistic screening."

A simple cut-off for waist-to-height ratio (0·5) can act as an indicator for cardiometabolic risk: recent data from adults in the Health Survey for England

“…Since it was first advocated in 2006 (63) , the simple message 'Keep your waist to less than half your height' has been recommended often (20,34,(64)(65)(66) . More recently, the 'Ashwell® String Test' (67) , which can broadly assess if the WHtR is below 0•5, even without a tape measure, has been suggested. This simple method is currently Government policy in Thailand (18) .…”

“…WHtR only requires a tape measure, making use of WHtR more costeffective. For the simplest dichotomous assessment (WHtR above 0•5), a piece of string is sufficient (67) . Strengths and limitations of our study…”

Nearly one third of adults in the ‘healthy’ BMI range are at early cardiometabolic risk according to their waist-to-height ratio

“…WHtR has the potential to be a simple indicator of the cardiometabolic risks associated with central adipose tissue. Its use in early screening would give greater opportunity for a substantial proportion of adults (nearly one third), who are in the ‘healthy’ BMI range but have high WHtR, to receive further screening ( 5 ) .…”

The Relationship between Certain Parental/Household Socio-Economic Characteristics and Female Adolescent Obesity in Montenegro

“…However, a main limitation of BMI is that it does not separate muscle tissue from fat tissue in the calculation nor the distribution of fat across certain body parts [36]. Therefore, many authors argue that the WHtR ratio should be used before BMI, for many reasons including the aforementioned ones [37][38][39][40][41][42][43][44].…”