The UK obesity epidemic is not without repercussions in the insurance industry. James Shattock explains.
Like many countries around the world, the UK has seen a dramatic increase in its population’s weight profile over the last decade or so.
As the topic of obesity gains increasing significance to the health of the nation there is a growing body of evidence suggesting that combining body mass index (BMI) and waist circumference is important in predicting health risk.
Medical and epidemiological studies regularly show that obesity increases the risk of developing a variety of conditions and diseases leading to a greater likelihood of morbidity (risk of ill-health) and mortality (risk of death).
There is now ample evidence to show that – like smoking before it – obesity increases the risk of a plethora of conditions including not only heart disease and diabetes, but also arthritis, liver disease, bone fractures and various types of cancer. Efforts at public education appear to have done little to curb what has been termed an epidemic of obesity.
An obese person is often defined as someone with a BMI of 30 or above. BMI is calculated using a simple formula: weight in kilogrammes divided by height in meters squared.
Table one (right) may be familiar to many readers. Originated by the World Health Organisation (WHO), it has since been adopted in many countries around the world – including the UK.
Graphs one and two (below left) from the Government’s 2007 Foresight Report on Tackling Obesity, illustrate the dramatic increase in the percentage of people classified as obese in each area and the rapid changes over a relatively short period of time, around six years. The graphs also show that the problem is UK-wide and clearly highlights those regions worst affected.
Obesogenic environment
Governments have produced many health policy papers on this topic, coining terms such as ‘obesogenic environment’ and vowing to tackle this uniquely modern epidemic.
Meanwhile, the television schedules are replete with programmes, like Celebrity Fat Camp and Supersize vs Superskinny, that cover this growing problem. Stomach-shrinking operations are performed with rapidly increasing regularity in the UK and, from April this year, slimming pills have been available over the counter without prescription. Obesity affects all sectors of society, with similar trends now being recorded in children.
Although BMI is generally recognised as a relatively crude indicator, its ease of calculation has helped establish it as the most commonly used measure in studies of obesity.
One of the main drawbacks of BMI is that it takes no account of body fat distribution. Adiposity (the presence of fat around the waist) has been recognised for many years as a strong predictor of increasing mortality and morbidity risk in its own right.
It is interesting to note (see table two) that the National Institute for Clinical Excellence’s (NICE) 2006 guidance on obesity incorporates measures of both waist and BMI in assessing health risks for adults.
Both waist circumference and hip to waist ratio are deemed by many experts to provide a better risk predictor than BMI. The main quibble is that historically there has not been an extensive body of data available for analysis.
In this context, a recent paper from the European Prospective Investigation (EPIC) into Cancer and Nutrition is essential reading.
Published in the New England Journal of Medicine in November 2008 as General and Abdominal Adiposity and Risk of Death in Europe, the study followed 360,000 participants in nine European countries over a mean follow-up of almost 10 years. Individuals with a history of cancer, heart disease or stroke were excluded, and all measurements were carried out by qualified medical practitioners.
The study investigates the association between BMI, waist circumference, waist-to-hip ratio and death. This article focuses purely on waist circumference, but interestingly the same conclusions reached here hold equally true for waist-to-hip ratio.
As expected, the study found that as BMI increases, so does the risk of death. The report found a similar relationship between waist circumference and death.
When BMI was combined with waist circumference, the study finds a clearer relationship with the risk of death. This means for people with a similar BMI, the risk of death increases, the bigger the waist. This is particularly true of those with a lower BMI but higher waist measurement.
The paper’s authors also highlight some other interesting results. Obesity, they note, is more strongly related to the risk of death among participants who had never smoked, whereas underweight was more strongly related to the risk of death among current smokers. But after adjusting for BMI, the association of waist circumference with the risk of death was stronger among smokers. This may be, the authors suggest, because smokers tend to have a metabolically more adverse fat-distribution profile than non-smokers.
All studies have their limitations of course. Despite excluding individuals with a history of cancer, heart disease or stroke, the authors accept that there remains a risk that other serious diseases might be included. However, they expect this to be small due to the nature of this long term study.
Overall, the study clearly shows that combining BMI and waist circumference allows for a more accurate differentiation between high and low risk individuals.
Metabolic syndrome
Metabolic syndrome, or insulin resistance, refers to a combination of health problems linked to an increased risk of early heart disease, stroke or diabetes.
The risk factors for metabolic syndrome include high waist-circumference, raised triglycerides, low HDL (good) cholesterol, high blood pressure and evidence of raised blood sugar levels.
While they may not necessarily be significant individually, a combination of these factors at raised levels or at the upper end of the normal range has been shown to indicate a higher risk profile.
Metabolic syndrome is linked to a doubling in the risk of coronary heart disease and a staggering five-times-higher risk of developing Type II Diabetes. The International Diabetes Federation estimates that a quarter of the world’s population has metabolic syndrome.
This is an entire topic in itself, so for the purpose of this article, we will just note the importance of waist circumference in the definitions for metabolic syndrome. There are three globally recognised definitions and each varies slightly. Increased waist circumference, however, is a key factor in all three.
As an industry, we should take a more proactive role in the ongoing health of our customers. This could take the form of an integrated ‘wellness’ programme, education zone or simply by providing a conduit to accessing information or helpful websites.
A Scottish Government report, SIGN Obesity in Scotland: Integrating Prevention with Weight Management, found that there are clear and significant health benefits associated with weight loss and we can all play a part in helping our customers achieve these.
Specifically, it found a 10kg weight loss resulted in many benefits: a 20% fall in mortality, a 30% fall in diabetes-related deaths and a 40% fall in obesity-related cancer deaths. It also reduced blood pressure, cholesterol and the risk of diabetes by 50%.
Obesity is a rapidly growing modern epidemic that will have increasing repercussions for the long-term health of both the general and insured populations. It is now clearly established that adiposity is a very important measure when assessing risk.
It is predicted that this simple waist measurement will become ingrained in the public perception as a key factor in health risk. It is also likely that more risk assessment routines, including those used in insurance, will be designed to take account of individuals with significantly large waist measurements.
James Shattock is actuarial pricing manager, Hannover Life Re (UK)
