How does DIETA Y MÁS save your life?
This idea was suggested to us when we read an article by Dr Margaret Ashwell OBE:
Dr Ashwell is an eminent researcher into obesity and associated risks. See, particularly, her scientific study, published in Obesity Reviews in 2012 (1).
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.
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).
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).