RENEW OR SUBSCRIBE TO PPM
Subscription is FREE for qualified healthcare professionals in the US.

Changing Obesity Measurement: Waist-to Height-Ratio

June 6, 2017
People should aim to keep their waist circumference to less than half their height to help prevent metabolic syndromes.

With Michelle Swainson, PhD

Toss the body mass index (BMI) scale, researchers have found that calculating a person's waist-to-height ratio may be a better estimate of risk of obesity and metabolic conditions—such as insulin resistance, type-2 diabetes, cardiovascular disease, and chronic pain.1,2

Waist-to-height ratio may be a better measure of obesity and risk of metabolic syndrome.

In a newly published study, researchers studied a group of 81 adults (40 women and 41 men) and measured whole-body fat percentage and abdominal fat (visceral adipose tissue, VAT) mass.1 They found that 36.5% more adults would be classified as obese using whole-body fat data rather than BMI.

To capture these results, the researchers, led by Michelle Swainson, PhD, a senior lecturer in exercise physiology at the Carnegie School of Sport at Leeds Beckett, gathered whole-body and VAT data using a total body dual-energy x-ray absorptiometry (DXA) scanner. They then calculated 5 predictors of whole-body fat and VAT:

  • BMI
  • Waist circumference
  • Waist-to-hip ratio
  • Waist-to-height ratio
  • Waist-to-height ratio0.05

According to the study, derived cut-points for predicting whole body obesity were 0.53 in men and 0.54 in women. The cut-point for predicting visceral obesity was 0.59 in both sexes.

"The conventional measurement of obesity used by primary care physicians is BMI. Although there are benefits of this method, there is concern that a lot of people are being classified as obese by BMI when they are not or are being missed by this classification when they need to be referred for help," said Dr. Swainson. For example, take the case of the person who has a normal BMI but high abdominal fat that is often missed.

"Whole-body fat percentage, and specifically VAT mass, are associated with health conditions including insulin resistance, type 2 diabetes, and cardiovascular disease, but are not fully accounted for through BMI evaluation," said.

The results of the study found that the best predictor of obesity was a waist-to-height ratio. The simple waist circumference divided by height measurement is not new to obesity study but despite evidence supporting its use, it is still not routinely measured in clinical practice, noted the researchers.

"Our waist-to-height broadly align to current guidelines that adults and children should kept their waist circumferences to less than half their height.," said Dr. Swainson, "By introducing this alternative measure, more men and women would potentially be referred to programs, such as weight loss management, to receive help in improving their health."

Also Excellent Screening Tool for Children

Researchers have also shown that waist-to-height ratio was a simple, effective and practical tool for mass screening childhood obesity and metabolic syndrome in China.2

In this study, 216,914 children and adolescents (age 7-17) from 6 cities in China were included. The researchers found that waist-to-height ratio was 0.968 in boys and 0.949 in girls for general obesity evaluation, and 0.983 in boys and 0.984 in girls for central obesity. The optimal cut-offs of waist-to-height ratio were 0.47 in boys and 0.45 in girls in the training set and validated in the testing set.

For metabolic syndrome evaluation, the sensitivity and specificity were 0.858 and 0.825 in boys, 0.864 and 0.812 in girls under the suggested cut-offs.

Pain and Obesity

Sensitivity to pain may be partly due to the pro-inflammatory state of the obese patient. Tumor necrosis factor-α (TNF-α) and intereukin-6 (IL-6) are important chemical mediators in the transmission of pain, owing to anti-inflammatory medication efficacy in analgesia.3 Adipose tissue (loose connective tissue that stores fat) is a major source of inflammatory mediators such as cytokines and chemokines. It was shown that markers such as IL-6 and c-reactive protein (CRP) were significantly related to percent of body fat and insulin sensitivity.4

Where a patient’s adipose tissue is distributed throughout their body also is an important factor regarding chronic pain. Visceral abdominal adipose tissue is more metabolically active and releases greater amounts of pro-inflammatory and insulin-resistant substances than other adipose tissue.5 Central adipose tissue also is associated with a higher likelihood of chronic pain independent of other markers of metabolic syndrome.6

Neuropathic Pain

Diabetes is a common cause of neuropathic pain and is a disease that is intimately tied to obesity. Up to half of all long-standing patient with diabetes have polyneuropathy, which is caused by mechanical stress that goes unnoticed because of loss of peripheral sensation.7

Musculoskeletal Pain

The obese patient commonly has to deal with many musculoskeletal pains. A national study in Australia showed that the odds of having arthritis were 7 times higher for the obese compared to those of normal weight.8 Overweight and obese patients have higher rates of low back and neck pain.9,10

Headaches

Headaches are a common problem in the general population; however, they are more common and incapacitating in the obese.11,12 BMI was shown to have a positive correlation with headache frequency in women. When examining cross-sectional analysis of 11 data sets of more than 220,000 women with a headache or migraine, a BMI of 20 was shown to be associated with the lowest risk for headache while those who had a BMI of 30 had a 35% increased risk; those women who were morbidly obese with a BMI of 40 were associated with even greater odds, showing an 80% increase for headache.13

 

Last updated on: June 14, 2017
Continue Reading:
Obesity and Pain Management
SHOW MAIN MENU
SHOW SUB MENU