Waist to height ratio (WHtR) is a person's waist divided by height. It is a measure of "early health risk". WHtR (weight to height ratio) is a simple primary screening risk assessment tool that identifies more people at ‘early health risk’ than a ‘matrix’, which uses a combination of BMI and WC. There is now good evidence that central obesity carries more health risks compared with total obesity assessed by body mass index (BMI). It has therefore been suggested that waist circumference (WC), a proxy for central obesity, should be included with BMI in a ‘matrix’ to categories health risk.
For adults over 20 years old, BMI falls into one of the following categories.
Female
0.63 and over = Highly obese
0.58 - 0.63 = Extremely overweight
0.53 - 0.58 = Overweight
0.46 - 0.53 = Healthy
0.43 - 0.46 = Slender & healthy
0.35 - 0.43 = Extremely slim
0.35 or below = Abnormally slim
Male
0.58 and over = Highly obese
0.54 - 0.58 = Extremely overweight
0.49 - 0.54 = Overweight
0.46 - 0.49 = Healthy
0.42 - 0.4 = Slender & healthy
0.35 - 0.42 = Extremely slim
0.35 or below = Abnormally slim
How we calculate WHtR ?
WHtR is an individual is calculated by the use of a mathematical formula.
The formula is – (Waist in centimetres) divided by (Height in centimetres)
WHtR boundary value is 0.5.
How to measure waist circumference and height 📏
Measure your waist - placing the tape horizontally halfway between your lowest rib and the top of your hipbone/1inch above the belly button.
Measure your height - from top of the head to the floor while standing erect and barefoot.
This boundary-value has been used around the world, and findings in many populations have supported the premise that WHtR is a simple and effective anthropometric index to, for example, identify health risks. WHtR seeks to cover a more complete picture of obesity by examining body fat percentage and internal adipose tissue mass.
As well as its close relationship with morbidity, WHtR also has a clearer relationship with mortality compared with BMI People with ‘healthy’ BMI and high WC are defined as being at ‘no increased’ risk. On the contrary, classification based on WHtR designates those with WHtR ≥0.5, as carrying an ‘increased risk’, irrespective of BMI status.
People who have a BMI in the ‘healthy’ range, but have WHtR >0.5, had risk factor levels that were less favourable than those in the ‘healthy’ BMI range with WHtR <0.5. Men were more likely than women to fall into this early 'increased' risk category, probably because of their greater propensity to central obesity.
What are the health-related issues due to an inappropriate WHtR value ?
Hypertension,
Dyslipidemia,
Cardiovascular diseases (CVD)
Diabetes mellitus and intermediate hyperglycemia
Metabolic syndrome
Obesity and overweight:
‘keep your waist to less than half your height’.
Hasini Arumadura
References
Prasad DS, Kabir Z, Suganthy JP, Dash AK, Das BC. Appropriate anthropometric indices to identify cardiometabolic risk in South Asians. WHO South-East Asia J Public Health 2013; 2(3-4): 142–148
https://www.coventrywarksapc.nhs.uk/Calculators/Waist-to-Height-Ratio
Ashwell, M. and Gibson, S. (2016) ‘Waist-to-height ratio as an indicator of early health risk: Simpler and more predictive than using a matrix based on BMI and waist circumference’, BMJ Open, 6(3).
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