Dieta y Más

How does DIETA Y MÁS save your life?

This idea was suggested to us when we read an article by Dr Margaret Ashwell OBE:

http://www.ashwell.uk.com/drmargaretashwell.htm
  Dr Ashwell is an eminent researcher into obesity and associated risks. See, particularly, her scientific study, published in Obesity Reviews in 2012 (1).
¿Por qué DIETA Y MÁS te salva la vida?

Dr Ashwell's 2012 study

The aim of this study (1) was to differentiate the screening potential of waist-to-height ratio (WHtR) and waist circumference (WC) for adult cardiometabolic risk in people of different nationalities and to compare both with body mass index (BMI). To this end, the research team undertook a systematic review and meta-analysis of 31 studies, showing that used WHtR had significantly greater discriminatory power compared with BMI for assessing the risk of hypertension, type-2 diabetes and general cardiovascular outcomes in both men and women. As the editorial in that same journal pointed out, for the first time, studies involving more than 300,000 adults in several ethnic groups, showed the superiority of WHtR over WC and BMI for detecting cardiometabolic risk factors in both sexes.

Precedents

Although these 2012 findings at first appeared absolutely new groundbreaking, a more thorough review of the scientific literature led us to realise that Dr Ashwell and her team had already published articles insisting on the importance of WHtR in diagnosis previously.

In fact, the 2012 study was the continuation of a systematic review published in 2010 (3), and both were preceded by figures obtained in the United Kingdom (4).

The study published in Nutrition Today in 2011 (5) reviewed the benefits and limitations of anthropometric measures to assess the health risks of obesity, stressing the use of WHtR as an indicator for central obesity and an important public health screening tool that can be used for all adults and children older than 5 years, in all ethnic groups, and that the use of a boundary value of WHtR 0.5 to denote increased risks converts into a simple message: ''Keep your waist circumference to less than half your height".

Also in 2011, another article (6) described the results from a systematic review showing that WHtR could be a useful global clinical screening tool, with a weighted mean boundary value of 0.5, for detecting cardiometabolic risk. A review, also published in The Open Obesity Journal (7), argues that WHtR should replace the traditional BMI measurement in order to improve efficacy in detecting cardiometabolic risk and provide substantial cost savings in terms of obesity treatment.

Other studies had previously been published to argue the need to review the most accurate anthropometric measures for determining cardiometabolic risk, both in adults (8-10) and in children and teenagers (11, 12).

Cardiometabolic risk

Patients with cardiometabolic risk are predisposed to arteriosclerosis and type-2 diabetes, which originate due to the association of conventional cardiovascular risk factors and alterations caused by metabolic syndrome. Amongst the latter, abdominal obesity and resistance to insulin are the most important (13).

Cardiometabolic risk is affected by disorders of the hydrocarbon metabolism and the lipids, and a proinflammatory and prothrombotic state, which form part of the metabolic syndrome, along with different atherogenic factors, including hypertension, cigarette smoking and hypercholesterolaemia. The identification of cardiometabolic risk is very important clinically, as energetic action aimed at the global control of the factors involved can help to prevent cardiovascular disease in all its manifestations and type-2 diabetes (14).

A different approach to obesity

The importance of WHtR came to the fore when it began to be suggested that BMI could no longer be considered a reference point and line to separate the healthy from the unhealthy, much more so when it began to be established that "weight-to-height ratio" is a more accurate indicator of risk to health and mortality because it translates an increase in fat in the abdomen, linked to a larger waist, and is related to metabolic disorders such as diabetes, arterial hypertension and dyslipidemia (15).

Today, this index is regarded as the main indicator in taking out life insurance and the annual premium to be paid. This is because WHtR is the best life expectancy predictor and, without doubt, a better predictor of the risk of mortality than the BMI (for example, a 30-year-old man with the highest BMI has a years-of-life-lost value of 10.5 years, whilst the same man with the highest WHtR has a years-of-life-lost value of 17 years. For a woman of the same age, the years-of-life-lost values are 5.3 and 9.5 years, respectively).
 

Bibliography
  1. Ashwell M, Gunn P, Gibson S. Waist-to-height ratio is a better screening tool than waist circumference and BMI for adult cardiometabolic risk factors: systematic review and meta-analysis. Obes Rev. 2012 Mar;13(3):275-86.
  2. Ashwell M: Plea for simplicity: use of waist-to-height ratio as a primary screening tool to assess cardiometabolic risk. Clinical Obesity 2012:doi:10.1111.
  3. Browning L, Hsieh S, Ashwell M. A systematic review of waist-to-height ratio as screening tool for the prediction of cardiovascular disease and diabetes: 0.5 could be a suitable global boundary value. Nutrition Research Reviews 2010; 23(2): 247-269.
  4. Ashwell M, Gibson S. Waist to height ratio is a simple and effective obesity screening tool for cardiovascular risk factors: analysis of data from the British National Diet and Nutrition Survey of adults aged 19 to 64 years. Obesity Facts 2009; 2(2): 97-103.
  5. Ashwell M. Shape: the waist-to-height ratio is a good, simple screening tool for cardiometabolic risk. Nutrition Today 2011;46:85-89.
  6. Ashwell M, Browning L. The increasing importance of waist-to-height ratio to assess cardiometabolic risk: a plea for consistent terminology. The Open Obesity Journal 2011;3:70-77.
  7. Ashwell M. Charts based on body mass index and waist-to-height ratio to assess the health risks of obesity: A review. The Open Obesity Journal 2011;3:78-84.
  8. Hsieh SD, Ashwell M, Muto T, Tsuji H, Arase Y, Murase T. Urgency of reassessment of role of obesity indices for metabolic risks. Metabolism 2010; 59(6): 834-40.
  9. Ashwell M. Obesity risk: importance of the waist-to-height ratio. Nurs Stand 2009; 23(41): 49-54.
  10. Ashwell M, Hsieh S. Six reasons why the waist-to-height ratio is a rapid and effective global indicator for health risks of obesity and how its use could simplify the international public health message on obesity. International Journal of Food Sciences and Nutrition, 2005; 56(5): 303-307.
  11. McCarthy HD, Ashwell M. A study of central fatness using waist-to-height ratios in UK children and adolescents over two decades supports the simple message--’keep your waist circumference to less than half your height’. Int J Obes (Lond) 2006; 30(6): 988-92.
  12. McCarthy HD, Ashwell M. Trends in waist:height ratios in British children aged 11-16 over a two-decade period. Proc Nutr Soc 2003; 62: 46A.
  13. Despres JP, Lemieux I. Abdominal obesity and metabolic syndrome. Nature 2006;444:881-7.
  14. Eckel RH, Grundy SM, Zimmet PZ. The metabolic syndrome. Lancet. 2005;365:1415-28.
  15. Ashwell M, Hardman A, Oliver M: Cardiovascular disease risk: a round table approach. How do factors related to diet, obesity, activity and drugs contribute to a combined strategy for prevention? Proc Nutr Soc 2000;59:415-416.


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