Measurement of waist hip ratio: In a lean person (left), the waist can be measured at its narrowest point, while for a person with convex waist (right), it may be measured at about one inch^[1] above the navel. The hip is measured at its widest portion of the buttocks at left, and at the great trochanters at right.

Waist–hip ratio or waist-to-hip ratio (WHR) is the ratio of the circumference of the waist to that of the hips. Failed to parse (Missing texvc executable; please see math/README to configure.): \tfrac{Waist}{Hip}

Measurement[link]

WHO protocol[link]

According to the World Health Organisation's data gathering protocol,^[2] the waist circumference should be measured at the midpoint between the lower margin of the last palpable rib and the top of the iliac crest, using a stretch‐resistant tape that provides a constant 100 g tension. Hip circumference should be measured around the widest portion of the buttocks, with the tape parallel to the floor.^[3] Other organizations use slightly different standards. The United States National Institutes of Health and the National Health and Nutrition Examination Survey used results obtained by measuring at the top of the iliac crest. Waist measurements are usually obtained by lay persons by measuring around the waist at the umbilicus, but research has shown that these measurements may underestimate the true waist circumference.^[3]

For both measurements, the individual should stand with feet close together, arms at the side and body weight evenly distributed, and should wear little clothing. The subject should be relaxed, and the measurements should be taken at the end of a normal expiration. Each measurement should be repeated twice; if the measurements are within 1 cm of one another, the average should be calculated. If the difference between the two measurements exceeds 1 cm, the two measurements should be repeated.^[3]

Practical measurement[link]

Practically, however, the waist is more conveniently measured simply at the smallest circumference of the natural waist, usually just above the belly button, and the hip circumference may likewise be measured at its widest part of the buttocks or hip.^[4] Also, in case the waist is convex rather than concave, such as is the case in pregnancy and obesity, the waist may be measured at a horizontal level 1 inch above the navel.^[1]

Indicator of health[link]

The WHR has been used as an indicator or measure of the health of a person, and the risk of developing serious health conditions. Research shows that people with "apple-shaped" bodies (with more weight around the waist) face more health risks than those with "pear-shaped" bodies who carry more weight around the hips.

WHR is used as a measurement of obesity, which in turn is a possible indicator of other more serious health conditions.

WHO STEPS states that abdominal obesity is defined as a waist–hip ratio above 0.90 for males and above 0.85 for females, or a body mass index (BMI) above 30.0.^[5] The National Institute of Diabetes, Digestive and Kidney Diseases (NIDDK) states that women with waist–hip ratios of more than 0.8, and men with more than 1.0, are at increased health risk because of their fat distribution.^[6]

A WHR of 0.7 for women and 0.9 for men has been shown to correlate strongly with general health and fertility. Women within the 0.7 range have optimal levels of estrogen and are less susceptible to major diseases such as diabetes, cardiovascular disorders and ovarian cancers.^[7] Men with WHRs around 0.9, similarly, have been shown to be more healthy and fertile with less prostate cancer and testicular cancer.^[8]

WHR has been found to be a more efficient predictor of mortality in older people than waist circumference or BMI.^[9] If obesity is redefined using WHR instead of BMI, the proportion of people categorized as at risk of heart attack worldwide increases threefold.^[10] The body fat percentage is considered to be an even more accurate measure of relative weight. Of these three measurements, only the waist–hip ratio takes account of the differences in body structure. Hence, it is possible for two women to have vastly different body mass indices but the same waist–hip ratio, or to have the same body mass index but vastly different waist–hip ratios.

Even in ancient civilizations globally, female representations are most often in the 0.6-0.7 range for WHR, suggesting a preference towards lower WHR.^[11]

Other studies have found that waist circumference, not WHR, to be a good indicator of cardiovascular risk factors,^[12] body fat distribution^[13] and hypertension in type 2 diabetes.^[14]

Measure of attractiveness[link]

The concept and significance of WHR as an indicator of attractiveness was first theorized by evolutionary psychologist Devendra Singh at the University of Texas at Austin in 1993.^[15][16] Singh argued that the WHR was a more consistent estrogen marker than the Bust–waist ratio (BWR) studied at King's College, London by Dr. Glenn Wilson in the 1970s.^[17][18]

Some researchers have found that the waist-hip ratio (WHR) is a significant measure of female attractiveness.^[19] Women with a 0.7 WHR are usually rated as more attractive by men from Indo-European cultures.^[20] Preferences may vary, according to some studies,^[21] ranging from 0.6 in China, South America, and some of Africa^[22] to 0.8 in Cameroon and among the Hazda tribe of Tanzania,^[8][23][24] with divergent preferences according the ethnicity of the observed being noted.^[25][26]

It appears that men are more influenced by female waist-size than hip-size:

"Hip size indicates pelvic size and the amount of additional fat storage that can be used as a source of energy. Waist size conveys information such as current reproductive status or health status ... in westernized societies with no risk of seasonal lack of food, the waist, conveying information about fecundity and health status, will be more important than hip size for assessing a female's attractiveness."

—Journal of Biological Psychology, ^[27]

To enhance their perceived attractiveness, some women may artificially alter their apparent WHR. The methods include the use of a corset to reduce the waist size and hip and buttock padding to increase the apparent size of the hips and buttocks. In an earlier attempt to quantify attractiveness, corset and girdle manufacturers of the 20th century used a calculation called hip spring^[28] (or hip-spring or hipspring), calculated by subtracting the waist measurement from the hip measurement. However this calculation fell into disuse because it is a poor indicator of attractiveness; for example, a hip spring of 10 inches (250 mm) would likely be considered quite attractive for an average-sized adult woman, but a child or petite woman with the same number would more likely be seen as malnourished.

Cognitive Ability[link]

Using data from the U.S. National Center for Health Statistics, William Lassek at the University of Pittsburgh in Pennsylvania and Steven Gaulin of the University of California, Santa Barbara, found a child's performance in cognitive tests correlated to their mother's waist-hip ratio, a proxy for how much fat she stores on her hips.^[29]

Children whose mothers had wide hips and a low waist-hip ratio scored highest, leading Lassek and Gaulin to suggest that fetuses benefit from hip fat, which contains long chain polyunsaturated fatty acids, critical for the development of the fetus's brain.^[29] In addition, evidence suggests that children of low-WHR teens were protected from the cognitive deficits often associated with teen birth.

See also[link]

• Body fat percentage
• Body Volume Index
• Body mass index
• Sagittal Abdominal Diameter (SAD)
• Index of Central Obesity
• Central obesity
• Physical attractiveness
• Sexual attraction
• Digit ratio
• Anogenital distance

References[link]

External links[link]

• Waist-hip ratio should replace body mass index as indicator of mortality risk in older people EurekAlert August 8, 2006
• Genes for 'pear shape' found, NHS Choices, October 11, 2010