Dangers from fat increasing by the year?

The BBC website “science” pages have text on obesity and a quiz about it. I am always interested in trying to find any real science basis behind our current obsession with obesity and diet. I still remain to be convinced by more than a scraping of it. (See old post about child obesity/anorexia scares. )

While I was scoring poorly on the quiz- I failed the first question on how many years of life obesity can cost – I saw this,:

Obesity can shorten your life by 9 years. 18 million days of work are lost through sickness due to obesity, and it costs the NHS £500 million a year.

I always have a problem with health rants that discuss how much problem x or y costs the Health Service. We get used to seeing things that put arbitrary cost figures on health. Unfortunately, no source is quoted, so it’s hard to argue with the data. But, an absence of facts never stops me making an argument.

Is every illness suffered by an obese person to be blamed on their weight? Don’t they get the same range of health problems as everybody else? So, any extra cost calculation would surely have to deduct a baseline standard level of health costs.

If obesity really shortens your life by 9 years, then surely you are saving the NHS 9 years worth of GP visits, dental treatment, precription costs? Assuming that someone’s medical treatment around the time of their death costs the same, whether it is in year x or year x+9, we must be seeing a net saving to the NHS? Even assuming the so-called obese person gets all sorts wrong with them in a few earlier years, there must still probably be a minus cost.

However, does obesity shorten life by 9 years? This figure is so precise that you assume it is based on some data. Ironically, a quick Googing produces this 1999 headline at Number 1- from the BBC, even 🙂

Obesity shortens life by four years

The article references research from Duke University. Blimey, has obesity got more than twice as life-threatening in the past 8 years?

They concluded that normal-weight adults had a life expectancy of 78, for overweight people it was 77, and for the most obese 74.

So, we’re talking about a year really, aren’t we, with a few more years for really huge people? Wait a minute, even this stuff doesn’t add up perfectly. The research was based on heart patients. Its applicability to people without heart disease is based on guesswork.

Heart disease is associated with being heavy. But there are also diseases associated with being very light, in which case something like osteoporosis would be the measure. Heavy people don’t tend to suffer from this. Don’t we get some health cost savings from people not having diseases associated with underweight?

Obesity shortens life span by 3 to 14 years: study (2003)
This one says obesity shortens life by between 3 and 14 years. It’s based on research in which

Dutch researchers looked at medical records from 3,457 volunteers in Framingham, Mass., from 1948 to 1990

This confused me a bit. It covers a convincingly large population, if a little too geographically focused (There might be other genetic or environmental factors in that location that don’t apply elsewhere.) But 3,457 “volunteers”? I assume that all 3,457 volunteers were dead or the research would be nothing like as convincing as it seems. So when did they volunteer?

….obese, male smokers were the worst off, losing 13.7 years of life compared to trim nonsmoking males. Obese, female smokers lost 13.3 years on average, the researchers found. Nonsmokers who were considered overweight by age 40 had their lives shortened by 3.3 years for women and 3.1 years for men.

queenstimes.com quotes the UK National Audit Office, “about 30,000 people die of obesity-related causes each year, cutting short their lives by about 9 years.”

Ah ha, a source for “9 years.” The same source is quoted by Wiltshire Health Promotion Service and the Cycle Network

Found it. UK National Audit Office (2001)

Producing the first authoritative estimates of the costs and consequences of obesity in England, Sir John estimated that obesity accounted for 18 million days of sickness absence and 30,000 premature deaths in 1998. On average, each person whose death could be attributed to obesity lost nine years of life. Treating obesity costs the NHS at least £½ billion a year. The wider costs to the economy in lower productivity and lost output could be a further £2 billion each year….. If prevalence continues to rise at the current rate, more than one in four adults will be obese by 2010. This would significantly increase the incidence of associated diseases, such as coronary heart disease, and would cost the economy over £3.5 billion a year by that date.

Well, we’re nearly there (2010) Are one in 4 adults obese yet? I must be looking athe wrong people. Or maybe I haven’t got a good enough obesity detector beacuse, when I look around in the street, I can’t see anything like this number of hugely overweight people.

Stop. Just check the wording before the hyperbole and random cost figures:
On average, each person whose death could be attributed to obesity lost nine years of life.

Note – each person whose death “could be attributed to obesity”. Now, I know there are people so heavy they can only get out of bed when Jerry Springer brings a crane. I agree there’s probably a fair chance that obesity might kill them.

But what about those people who are “obese” because they are 10% heavier than the ideal for their height. That would be between ten to twelve pounds on my weight and height. I am pretty certain I could gain ten pounds without threatening my lifespan. And if I were to gain a stone and die, I still suspect my death couldn’t be attributable to “obesity.”

Oh, wait, 9 years is too low an estimate for Healthspan Express Obesity Cuts Lifespan by Up to 20 Years.(2003) Referring to 2 research projects:

The researchers have found that young, obese white men live 13 fewer years than expected and very obese white women lose 8 years. The news is even worse for young, obese black men whose life span’s (sic) are shortened by 20 years.

OK then? Which is it – anywhere between 1 or 20 years. Now that’s what I call a generous cobfidence interval.

It looks rather as if the estimates of years-of-life-lost get a year or two longer for every year of earth life between reports. Obesity is apparently becoming more and more dangerous with every passing year. Maybe there is really a raging epidemic of obesity then.

That must be the case, otherwise the use of this research would surely just be bad science. And that could never happen.

3 thoughts on “Dangers from fat increasing by the year?

  1. Pingback: University Update

  2. Mathematics and statistics has always seemed out of the grasp of the people who create these scare stories.

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