Body mass index

src: advancedcardioservices.com

The body mass index ( BMI ) or Quetelet index is a value derived from mass (weight) and individual height. BMI is defined as body mass divided by the square of height, and is universally expressed in units of kg/m ² , which results from mass in kilograms and height in meters.

BMI can also be determined using tables or graphs that display BMI as a mass and high function using contour or color lines for different BMI categories, and which can use other units of measurement (converted to metric units for calculation).

The BMI is an attempt to measure the amount of tissue mass (muscle, fat, and bone) in an individual, and then categorize the person as body weight , normal weight , overweight , or obesity based on that value. The categorization is the subject of some debate about where on the BMI scale the dividing line between categories should be placed. The commonly accepted BMI range is underweight: under 18.5 kg/m ² , normal weight: 18.5 to 25, overweight: 25 to 30, obese: over 30. Persons Asia has different associations between BMI, body fat percentage, and health risks compared with European descent, with a higher risk of type 2 diabetes and cardiovascular disease in BMI lower than the WHO cut-off point for overweight, 25 kg/m ² , although the cutoff for observed risk varied among different Asian populations.

Video Body mass index

History

The foundation of BMI was designed by Adolphe Quetelet, a Belgian astronomer, mathematician, statistician and sociologist, from 1830 to 1850 during which he developed what he called "social physics". The term "body mass index" (BMI) for modern human to high-squared weight ratio was created in a paper published in the July 1972 issue of the Journal of Chronic Diseases by Ancel Keys and others.. In this paper, Keys argues that what he calls BMI is "... if not entirely satisfactory, at least as good as other relative weight indexes as an indicator of relative obesity"

Interest in the index that measures body fat comes with increasing obesity in a prosperous Western society. BMI is explicitly quoted by Keys that are appropriate for population studies and are not appropriate for individual evaluation. However, because of its simplicity, it has been widely used for early diagnosis. Additional metrics, such as waistlines, can be more useful.

BMI secara universal dinyatakan dalam kg/m ² , yang dihasilkan dari massa dalam kilogram dan tinggi dalam meter. Jika pound dan inci digunakan, faktor konversi 703 (kg/m ² )/(lb/di ² ) harus diterapkan. Ketika istilah BMI digunakan secara informal, unit biasanya dihilangkan.

${\ displaystyle \ mathrm {BMI} = {\ frac {{\ text {mass}} _ {\ text {kg}}} {{\ text {height}} _ {\ text {m}} ^ {2}}} = {\ frac {{\ text {mass}} _ {\ text {lb}}} {{\ text {height}} _ {\ text {in}} ^ {2}}} \ kali 703}  ÂÂ$

BMI provides a simple numerical measure of the thickness of one's or thinness , enabling health professionals to discuss weight issues more objectively with their patients. BMI is designed to be used as a simple way to classify the average sedentary population (not physically active), with average body composition. For these individuals, the current recommendation score is as follows: BMI from 18.5 to 25 kg/m ² may indicate optimal weight, BMI lower than 18.5 indicates the person is underweight , a number from 25 to 30 may indicate the person is overweight, and a number from 30 upwards indicates that the person is obese. Lean athletes often have high muscle ratios and therefore high BMIs are misleading relative to their body fat percentage.

Maps Body mass index

Scalability

BMI is proportional to mass and inversely proportional to the high square. So, if all the dimensions of the body are double, and the mass scale naturally with the high cube, then the BMI doubling instead remains the same. This results in a higher person having an unusually high BMI reported, compared to their actual body fat levels. For comparison, the Ponderal index is based on the natural scale of the mass with a third force of altitude.

However, many of the taller people not only "lengthen" short people but tend to have narrow skeletons proportional to their height. Carl Lavie has written that, "Table B.M.I. is excellent for identifying obesity and body fat in large populations, but they are much less reliable for determining obesity in individuals."

src: www.vertcenters.com

Category

The frequent use of BMIs is to assess how much weight a person is leaving from what is normal or desirable for a person's height. Being overweight or deprived can, in part, be accounted for by body fat (adipose tissue) even though other factors such as muscle also affect BMI significantly (see discussion below and overweight).

WHO considers BMI less than 18.5 as underweight and may indicate malnutrition, eating disorders, or other health problems, while BMIs equal to or over 25 are considered overweight and over 30 are considered obese. This BMI value range is only valid as a statistics category.

BMI in children (ages 2 to 20)

BMI is used differently for children. This is calculated in the same way as for adults, but then compared with the typical values ​​for other children of the same age. Instead of comparison with fixed thresholds for underweight and overweight, BMI was compared against percentiles for children of the same gender and age.

A BMI less than the 5th percentile is considered less severe and above 95 percent is considered obese. Children with BMI between the 85th and 95th percentiles are considered overweight.

Recent studies in the UK show that women between the ages of 12 and 16 have a higher BMI than men of the same age averaging 1.0 kg/m ^{2 International variation}

This recommended distinction along a linear scale may vary over time and from one country to another, making a global survey, longitudinal becoming problematic.

Hong Kong

The Hong Kong Hospital Authority recommends using the following BMI ranges:

Japanese

Japanese Society for the Study of Obesity (2000):

Singapore

In Singapore, the BMI cut-off rate was revised in 2005, motivated by research showing that many Asian populations, including Singapore, have higher body fat proportions and an increased risk for cardiovascular disease and diabetes mellitus, compared with Caucasians in the same BMI. Cut-off BMI is presented with an emphasis on health risks rather than weight.

United States

In 1998, the US National Institutes of Health and the Centers for Disease Control and Prevention brought the US definition in accordance with World Health Organization guidelines, lowering the normal/overweight limits of BMI 27.8 to BMI 25. It has the effect of redefining some 29 million Americans , previously healthy , for overweight .

This can partly explain the improvement of overweight diagnosis in the last 20 years, and increased sales of weight loss products over the same time. WHO also recommends lowering the normal/overweight threshold for Southeast Asian body types to around BMI 23, and expects further revisions to emerge from clinical studies of different body types.

The 1994 US National Health and Nutrition Survey showed that 59.8% of American men and 51.2% of women had a BMI of over 25. Morbid obesity - BMI 40 or more - was found in 2% of men and 4% of women. A survey in 2007 showed 63% of Americans were overweight or obese, with 26% in the obesity category (BMI 30 or more). By 2014, 37.7% of adults in the United States are obese, categorized as 35.0% of men and 40.4% of women; grade 3 obesity (BMI over 40) was 7.7% for men and 9.9% for women.

There are differences of opinion about the definition of underweight in women; doctors cite anything under 18.5 to 20 as underweight. The most frequently stated is 19. The near-15 BMI is usually defined as hunger and BMI less than 17.5 as the informal criteria for the diagnosis of anorexia nervosa.

src: previews.123rf.com

High level consequences for adults

The BMI range is based on the relationship between weight and illness and death. Overweight and obese individuals are at increased risk for the following diseases:

• Coronary artery disease
• Dyslipidemia
• Type 2 diabetes
• Gallbladder disease
• Hypertension
• Osteoarthritis
• Sleep apnea
• Stroke
• At least 10 cancers, including endometrial, breast, and colon cancers.
• Epidural lipomatosis

Among people who never smoked, overweight/obesity was associated with a 51% increase in mortality compared to people who always had normal weight.

src: blog.pregistry.com

Apps

Public health

BMI is commonly used as a means of correlation between groups associated with general mass and can serve as a vague means of estimating adiposity. The duality of the BMI is that, while it is easy to use as a general calculation, it is limited to how accurate and relevant the data is obtained from it. Generally, the index is suitable for recognizing trends in persistent or overweight individuals as there is a smaller margin of error. BMI has been used by WHO as a standard for recording obesity statistics since the early 1980s.

This general correlation is particularly useful for consensus data on obesity or other conditions because it can be used to construct semi-accurate representations from which solutions can be established, or the RDA for groups can be calculated. Similarly, it is becoming increasingly relevant to the growth of children, due to the fact that the majority of children are inactive.

Clinical practice

The BMI category is generally regarded as a satisfactory tool for measuring whether an inactive person is underweight , overweight , or obesity with exceptions, such as : athletes, children, the elderly, and the weak. Also, a child's growth is documented against the measured BMI growth chart. The obesity trends can then be calculated from the difference between BMI and BMI on the chart. In the United States, BMI is also used as a measure of underweight, due to advocacy on their behalf with eating disorders, such as anorexia nervosa and bulimia nervosa.

Legislation

In France, Israel, Italy and Spain, legislation has been introduced banning the use of fashion show models having a BMI under 18 years old. In Israel, a BMI under 18.5 is prohibited. This is done to counter anorexia between models and people who are interested in fashion.

src: www.eser.lk

Limitations

Medical establishments and statistical communities have both highlighted the limitations of BMI.

Mathematician Keith Devlin and the restaurant industry association of the Center for Consumer Freedom argue that the errors in BMI are significant and so widespread that they are generally useless in health evaluations. University of Illinois political science professor Eric Oliver says BMI is a comfortable yet inaccurate weight measure, which is forced into society, and should be revised.

Scaling

The exponent in the denominator of the formula for BMI is arbitrary. BMI depends on body weight and height square . Because the mass increases to the strength linear dimension, the higher individual with the exact same body shape and composition relative has a larger BMI.

The mathematician Prof. Nick Trefethen, who observes this, says, "BMI divides the weight of an amount too large for short people and too small for tall people, so short people are misled thinking they are thinner than they are, and tall people are misled thinking they are more fat. "

For US adults, exponential estimates range from 1.92 to 1.96 for men and 1.45 to 1.95 for women.

Ignoring variations in physical characteristics

The BMI overestimates about 10% for large (or high) frames and underestimates about 10% for smaller frames (short stature). In other words, people with small frames will carry more fat than optimal, but their BMIs reflect that they are normal . In contrast, large-framed individuals (or tall) may be reasonably healthy, with a relatively low body fat percentage, but are classified as overweight by BMI.

For example, a height/weight chart can say ideal weight (BMI 21.5) for men 5Ã, ft 10Ã, (178 cm) is 150 pounds (68 kg). But if the man has a slim body (small frame), he may be overweight at 150 pounds (68 kg) and should be reduced by 10%, to about 135 pounds (61 kg) (BMI 19.4). Conversely, men with larger skeletons and more dense body shapes will increase by 10%, to about 165 pounds (75 kg) (BMI 23.7). If a person rocks on the edge of small/medium or medium/large, common sense should be used in calculating one's ideal body weight. However, falling into the ideal weight range for a person's height and build is not yet accurate in determining health risk factors such as waist/height ratio and actual body fat percentage.

Accurate frame size calculators use multiple measurements (wrists, elbow width, neck circumference and so on) to determine which category a person falls into a certain height. BMI also fails to account for the loss of height through aging. In this situation, the BMI will increase without the appropriate weight increase.

Does not differentiate between muscle mass and fat mass

The assumption about the distribution between muscle mass and fat mass is not appropriate. BMI generally exaggerates adiposity in those with leaner body mass (eg, athletes) and underestimates the advantages of adiposity in those with less lean body mass. A study in June 2008 by Romero-Corral et al. studied 13,601 subjects from the third National Health and Nutrition Examination Survey (NHANES III) of the United States and found that BMI obesity (BMI & gt; 30) was present in 21% of men and 31% of women.

Using body fat percentage (BF%), however, BF-defined obesity is found in 50% of men and 62% of women. While BMI obesity was defined to indicate high specificity (95% for men and 99% for women), BMI showed poor sensitivity (36% for men and 49% for women). Despite this undercounting of obesity by BMI, BMI scores in the medium BMI range of 20-30 were found to be associated with various body fat percentages. For men with a BMI of 25, about 20% have a body fat percentage below 20% and about 10% have a body fat percentage above 30%.

BMIs are very inaccurate for a very fit or athletic person, because their high muscle mass can classify them in BMI overweight categories, even though their body fat percentage often falls within the 10-15% category. , which is below the more inactive person from the average build that has a normal BMI number . For example, bodybuilders and eight times Mr. Olympia Ronnie Coleman would be considered a morbidly obese based on his BMI 41.8. Body compositions for athletes are often better calculated using body fat sizes, as determined by techniques such as measurement of skin folds or underwater weights and manual measurement limitations have also led to new alternative methods for measuring obesity, such as body volume index.

Variations in category definitions

It is not clear where on the BMI scale the threshold for overweight and obesity should be established. Because of this standard has changed over the last few decades. Between 1980 and 2000, US Dietary Guidelines have defined overweight at various levels ranging from BMI 24.9 to 27.1. In 1985 the National Institutes of Health Consensus conference (NIH) recommended that BMI overweight be set at a BMI of 27.8 for men and 27.3 for women.

In 1998, the NIH report concluded that BMIs over 25 were overweight and BMIs over 30 were obese. In the 1990s the World Health Organization (WHO) ruled that a BMI 25-30 should be considered overweight and a BMI of over 30 was obese, a standard set of NIH. This becomes the definitive guide to determine if a person is overweight.

The current WHO and NIH range of normal weight loss has been shown to be associated with a reduced risk of some diseases such as type II diabetes; However using the same range of BMI for men and women is considered arbitrary, and making the definition of underweight is not very suitable for men.

One study found that most people labeled 'overweight' and 'obesity' by current definition actually did not face a significant increase in risk for premature death. In a quantitative analysis of a number of studies, involving more than 600,000 men and women, the lowest mortality rate was found for people with BMI between 23 and 29; most of the 25-30 range considered 'overweight' is not associated with higher risk.

Variations in health relations

A study published by the Journal of the American Medical Association JAMA in 2005 showed that overweight people had mortality rates similar to < i> normal burden people as defined by BMI, while skinny and obesity people have higher mortality rate.

A study published by the The Lancet in 2009 involving 900,000 adults showed that overweight and body weight both had a higher mortality rate high from normal weighs people as defined by BMI. The optimal BMI was found to be in the range of 22.5-25.

High BMI is associated with type 2 diabetes only in people with high serum gamma-glutamyl uptake transpus.

In an analysis of 40 studies involving 250,000 people, patients with coronary artery disease with normal BMI were at a higher risk of death from cardiovascular disease than those in whom BMI placed them in excess weight body range (BMI 25-29.9).

One study found that BMI has a good general correlation with body fat percentage, and noted that obesity has taken over smoking as the number one cause of death in the world. But it also noted that in the study 50% of men and 62% of women were obese based on obesity determined by body fat, while only 21% of men and 31% of women were obese by BMI, meaning that BMI was found to be underestimated. number of obese subjects.

A 2010 study that followed 11,000 subjects for eight years concluded that BMI is not a good measure for the risk of heart attack, stroke or death. Better sizes found waist-to-high ratio. A 2011 study that followed 60,000 participants up to 13 years found that waist-to-hip ratio was a better predictor of death of ischemic heart disease.

src: previews.123rf.com

Alternative

BMI Prime

BMI Prime, a modification of the BMI system, is the actual BMI ratio for the optimal upper limit BMI (currently defined at 25 kg/m ² ), ie, the actual BMI is expressed as the proportion of the optimal limit. The actual weight to weight ratio for the upper limit of optimal BMI (25 kg/m ² ) is the same as BMI Prime. BMI Prime is a dimensionless number that is separate from the unit. Individuals with BMI Prime less than 0.74 are underweight; those with 0.74 and 1.00 have optimal weight; and those who are 1.00 or more are overweight. BMI Prime is clinically useful because it shows what ratio (eg 1.36) or percentage (eg 136%, or 36% above) a person deviates from optimal optimal BMI.

For example, a person with a BMI of 34 kg/m ² has a BMI Prime 34/25 = 1.36, and 36% above their upper mass limit. In the South East Asian and South China populations (see Ã, Â international variations), BMI Prime should be calculated using the upper limit BMI 23 in its denominator, not 25. BMI Prime allows easy comparison between populations with different upper BMI bounds.

Waistline

The waist circumference is a good indicator of visceral fat, which raises more health risks than fat elsewhere. According to the US National Institutes of Health (NIH), waist circumference greater than 102 cm (40 inches) for men and 88 cm (35 inches) for women (not pregnant), is considered to imply a high risk for type 2 diabetes, dyslipidemia, hypertension, and CVD. Waist circumference can be an indicator of the risk of obesity-related illness better than BMI. For example, this is the case in Asian and parent populations. 94 cm (37 inches) for men and 80 cm (31 inches) for women expressed as having a "higher risk", with a "higher" NIH score.

The waist to hip ratio has also been used, but has been found to be no better than waist circumference alone, and more complicated to measure.

The related indicator is waist circumference divided by height. Values ​​showing increased risk are: greater than 0.5 for people under 40, 0.5 to 0.6 for people aged 40-50 years, and greater than 0.6 for people over 50.

Surface-based body index

The Surface Body Based Body Index (SBSI) is much more stringent and is based on four key measurements: body surface area, vertical trunk circumference, waist circumference and height. Data on 11,808 subjects from the National Health and Human Nutrition Examination Survey (NHANES) 1999-2004, showed that SBSI outperformed BMI, waist circumference, and A Body Shape Index (ABSI), an alternative to BMI.

${\ displaystyle \ mathrm {SBSI} = {\ frac {({\ text {H}} 7/4}) ({\ text {WC }} 5/6})} {\ text {BSA VTC}}}} Â Â$

The simplified and non-dimensional form of SBSI, known as SBSI ^* , has also been developed.

${\ displaystyle \ mathrm {SBSI ^ {\ star}} = {\ frac {({\ text {H}} 2) ({\ teks {WC}}}} {\ text {BSA VTC}}}} Â Â$

Indeks massa tubuh yang dimodifikasi

In some medical contexts, such as familial amyloid polyneuropathy, serum albumin is calculated to produce modified body mass index (mBMI). MBMI can be obtained by multiplying BMI by serum albumin, in grams per liter.

src: www.onlinejacc.org

See also

• Alometry
• Body fat percentage (BFP)
• Body water
• Self-Victim Index
• List of countries by Body Mass Index (BMI)
• Paradoxic obesity

src: medical.azureedge.net

Note

src: 4.bp.blogspot.com

References

src: thumbs.dreamstime.com

Further reading

• Ferrera LA, ed. (2006). Focus on Body Mass Index and Health Research . New York: Nova Science. ISBN 978-1-59454-963-2.
• Samaras TT, ed. (2007). Human Body Size and Scale Law: Physiological, Performance, Growth, Longevity, and Ecological Herb . New York: Nova Science. ISBN: 978-1-60021-408-0. Ã,
• Sothern MS, Gordon ST, von Almen TK, eds. (2006). Pediatric Obesity Handbook: Clinical Management (illustration ed.). Press CRC. ISBNÃ, 978-1-4200-1911-7

src: www.40fit.com

External links

• US. National Center for Health Statistics:
  • BMI Charts Growth for children and young adults
  • BMI calculator age 20 and above

Source of the article : Wikipedia