Indicator of health
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.
A WHR of 0.7 for women and 0.9 for men have 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. Men with WHRs around 0.9, similarly, have been shown to be more healthy and fertile with less prostate cancer and testicular cancer.
WHR has been found to be a more efficient predictor of mortality in older people than waist circumference or body mass index (BMI). If obesity is redefined using WHR instead of BMI, the proportion of people categorized as at risk of heart attack worldwide increases threefold. 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.
The ideal ratio for women is considered to be about 0.7.
Measure of attractiveness
The concept and significance of WHR is as an indicator of attractiveness.WHR was a more consistent estrogen marker than the BHR studied at King's College, London by Dr Glenn Wilson in the 1970s.
Women with a 0.7 WHR are usually rated as more attractive by men from European cultures. Beauty icons such as Marilyn Monroe and Sophia Loren have or had ratios close to 0.7, even though they have different weights and heights. In other cultures, preferences appear to vary according to some studies,ranging from 0.6 in China, to 0.8 or 0.9 in parts of South America and Africa, and divergent preferences based on ethnicity, rather than nationality, have also been noted.
For example, women of African descent tend to store their fat in their buttocks more than women of other groups. Therefore, their WHR as viewed from the front may appear to be much greater than when viewed from the side. The inverse may be true of women of East Asian ancestry. Therefore, African men appear to be more likely to value a woman's small WHR in profile and Asian men may tend to place more value on a smaller frontal WHR, compared to European men.
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."
The body mass index (BMI), or Quetelet index, is a statistical measure of body weight based on a person's weight and height. Though it does not actually measure the percentage of body fat, it is used to estimate a healthy body weight based on a person's height. Due to its ease of measurement and calculation, it is the most widely used diagnostic tool to identify weight problems within a population, usually whether individuals are underweight, overweight or obese.
Body mass index is defined as the individual's body weight divided by the square of his or her height.
The formulae universally used in medicine produce a unit of measure of kg/m2.
BMI can also be determined using a BMI chart, which displays BMI as a function of weight (horizontal axis) and height (vertical axis) using contour lines for different values of BMI or colours for different BMI categories.
BMI provided a simple numeric measure of a person's "fatness" or "thinness", allowing health professionals to discuss over- and under-weight problems more objectively with their patients. However, BMI has become controversial because many people, including physicians, have come to rely on its apparent numerical authority for medical diagnosis, but that was never the BMI's purpose; it is meant to be used as a simple means of classifying sedentary (physically inactive) individuals with an average body composition.
For these individuals, the current value settings are as follows:
- a BMI of 18.5 to 25 may indicate optimal weight;
- a BMI lower than 18.5 suggests the person is underweight
- while a number above 25 may indicate the person is overweight;
- a BMI below 17.5 may indicate the person has anorexia nervosa or a related disorder;
- a number above 30 suggests the person is obese
- over 40, morbidly obese).
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