Wednesday, 29 June 2011

Obesity rate is twice as high amongst nonsmokers

A study published in this week's British Medical Journal shows that nonsmokers are twice as likely to be obese—and three times as likely to be severely obese—than smokers. This is very interesting stuff, because it is is often said that smokers put on weight when they quit cigarettes. It's also said, albeit much less often, that there is some correlation between the decline in smoking and the rise in obesity. This study offers empirical evidence for both.

The connection between smoking and low weight is not much commented on, presumably because anti-smoking campaigners don't want people who are worried about their weight to 'reach for a Lucky instead of a sweet', as the old advertising campaign went. And yes, I've reproduced that advert here to annoy them.

Why, then, would any public health researcher jeopardise their future funding by highlighting this fact? The answer is that they didn't set out to. The study in question looks at obesity's role in creating health inequalities (a cast-iron guarantee for funding). Social class is closely related to mortality and life expectancy is lowest amongst the lowest social classes. Smoking is one reason for that, obesity is another. Between them, as this study shows, these two risk factors account for more than half the difference in life expectancy between the top and bottom rungs of society.

That, in itself, is useful and important information, but in the process of comparing smoking and nonsmoking women (and it was only women in this study), they also show that the difference in obesity rates between smokers and nonsmokers is, frankly, massive.



The graph above (click to enlarge) shows the percentage of women who are overweight and obese according to smoking status and occupational class. As expected, the highest occupational classes (I and II) have a lower rate of obesity than the lowest.

Also as expected, the smokers weigh less than the nonsmokers. What is surprising is the size of the difference. In most cases, rates of obesity are around twice as high for nonsmokers and, across all groups, rates of severe obesity are three times as high.

As the study says:

Severe obesity was more than twice as prevalent among women who had never smoked in the lower occupational classes than in women who had never smoked in the higher occupational classes and about seven times more prevalent than among current smokers in the higher occupational classes.

Another way to look at it is that nonsmokers in the highest social class have a higher rate of obesity (13.3%) than smokers in the lowest social class (13.1%). Rates of severe obesity—which is a condition popularly associated with the underclass—is actually more common amongst the highest class of nonsmoker than the lowest class of smoker. No matter which class you look at, obesity rates are always higher amongst nonsmokers.

To use the standard language of public health, it is true to say that not smoking is a major risk factor for obesity. This, of course, should not be taken as a green light to take up smoking. As the researchers point out, the health risks of smoking are greater than the health risks of obesity. The study shows that the mortality rate rises by around a third for moderately obese people and doubles for severely obese people. By comparison—as the same authors showed in an earlier paper—smoking increases the mortality rate by at least 75%.

I discussed the reasons why smokers tend to be less fat in Chapter 3 of Velvet Glove, Iron Fist. Partly, it is the result of nicotine suppressing appetite and partly it is the act of smoking which takes the mind off food, but mainly it is the physiological effect of nicotine that increases the metabolic rate, particularly during exercise. In his excellent, but sadly out-of-print, book Smoking: The Artificial Passion, David Krogh says that smokers, on average, weight seven pounds less than nonsmokers. Judging by this new study in the BMJ, that is probably an underestimate.

As I see it, there are two useful messages to take home from this study. The first is brought out in the study itself:

[The results] suggest the decline in smoking rates in recent decades may have contributed to the increase in overweight and obesity.

This is worth bearing in mind when you hear anti-smoking-turned-anti-obesity windbags like John Banzhaf rattling on. People like him have, in a real sense, created the problem he professes to be so concerned about. You can, of course, make a rational case for saying that obesity is less of a health problem than smoking, but you won't hear it from him. (One might even frivolously consider that since Big John's so keen to bring in a 'fat tax', there is an easy way to do it—tax nonsmokers. Sure, not all nonsmokers develop obesity-related diseases but then not all smokers get smoking-related diseases. Not all people who drink soda or eat burgers get fat either, but then taxing people on the basis of risk factors to aggregate populations is perfectly acceptable, isn't it John?)

If the suppression of smoking has indeed led to a rise in over-eating, it just goes to prove the golden rule of prohibition: people will always find some unhealthy pleasure to indulge in when other avenues are closed off. If, by some miracle, the war on obesity is won, it will only lead to excessive use of something else. The whole prohibitionist exercise is futile because the desire for pleasure is a zero sum game.

The second point to consider is that since nicotine is an aid to maintaining a healthy weight, why are alleged health campaigners banning products like snus and e-cigarettes which not only get people off cigarettes but could control their weight as well? If smoking and obesity really are the two greatest public health threats of our time, doesn't that make ultra-low risk nicotine products the penicillin of the age?

13 comments:

auntieban said...

Since they banned ALL smoking (indoor and outdoor) at Rampton, the No. 1 health problem has been obesity. Presumably, it's the same at all other enforced 'smokefree' places

And, while on the only slightly OT subject of Rampton, should we not, by now, be hearing of all the wonderful improvements to health that these people must be experiencing? Like a dramatic reduction in heart attacks, for instance?

Mark Wadsworth said...

Glorious. For sure, we've always known this to be the case, but it's nice to have somebody else say it. Isn't there also a correlation between decline in smoking and childhood asthma?

Add to that the correlation between "pensions time bomb" and decline in smoking and it's starting to look as if the benefits of smoking outweigh the costs :-)

Trooper Thompson said...

Mark, that rise in asthma corresponding to the decline in smoking hasn't stopped the puritans claiming it's the smokers' fault.

Anonymous said...

And of course, there's always that amazing correlation between the sharpest-ever rise in cot deaths in the 1970's and early 80's which coincided precisely with the sharpest-ever decline in the number of smokers, and which only started to plateau out once the decline in smokers did the same …

But, rather as TT points out above, that inconvenient little truth hasn’t stopped the anti brigade from blaming SIDS on ETS, either.

Arrogance just doesn’t describe it. These people have more front than Sainsbury’s.

Anonymous said...

The overweight/obesity epidemic dates to 1998 and has nothing to do with smoking rates.

Govt changed the guidelines and, overnight, 30 million Americans found themselves to be overweight or obese.

Those 30 million had not gained one pound in weight.

Gary K.

Junican said...

Most of our soldiers are not very tall, but they are 'thick set' and very strong. The probability is that they would be described as 'obese' if the definition of obesity is based upon body-mass index. As far as 'body-mass index' is concerned, there is no difference between muscle and fat.

CORRUPTION, CORRUPTION, CORRUPTION! When will it end?

John Savage said...

Why are alleged health campaigners banning products like snus and e-cigarettes?

Could it be that Big Pharma are researching nicotine-based weight loss drugs?

http://www.bloomberg.com/news/2011-06-09/nicotine-may-lead-to-discovery-of-new-weight-loss-drugs-scientists-say.html

Junican said...

Further to the above.

A soldier who is 5' 8" and weighs 13 stones is 'overweight'. (according the the body-mass index, he registers 27.7 on the scale, which is 'overweight' but not 'obese'. A similar soldier who weighs 15 stones is 'obese' (on the scale, anyone with an index of greater than 30 is 'obese' -such a soldier, as described, measures 31.9 on the scale) - regardless of whether or not his weight is all muscle or all fat. So a soldier who is 5' 8" tall and is as strong as an ox, and weighs 15 stone is obese!

How do these ignoramuses get away with it? THERE IS NO SUCH THING AS A STANDARD HUMAN BEING!!!

Anonymous said...

THERE IS NO SUCH THING AS A STANDARD HUMAN BEING!!!

Ahh and there you have hit the nail very firmly on the head. It is this simple fact that seems to offend the puritans almost more than anything else.

Anonymous said...

"Could it be that Big Pharma are researching nicotine-based weight loss drugs?"

Quite possibly, because that's the only plant chemical in tobacco that most people have heard of.

It was the only one the prohibitionists knew about and it was used as a pesticide, which was handy for labelling people as deviant.

For instance they tried to cure ulcerative colitis with nicotine.

Turned out that the benefit smokers experience from an after dinner cigar was the inhaled carbon monoxide,apparently now known to be a normal part of the digestive system.

Could it really be the effects the vitamin K , the ubiquinone, solanesol, nitric oxide, tyrosine or even the carbon monoxide again?

Who knows?

But the belief lies with nicotine.
Though very few people know that they eat tiny amounts of it everyday in vegetables and if there is a genuine rise in obesity,it doesn't seem to be working.

But I very much doubt anyone will look elsewhere.

Rose

James Higham said...

So let me get this straight - it's a choice between lung cancer and heart disease. Hmmm.

Anonymous said...

"So let me get this straight - it's a choice between lung cancer and heart disease. Hmmm."
Barring violence, accident, starvation and infectious diseases then yes most people who survive beyond the age of 70 will die of either cancer or heart disease. I believe it is called mortality.

No one leaves here alive.

Ella Robbins said...

Thought you'd be interested in this economic analysis of the causes for adult obesity, written in 2002:

http://www.ppge.ufrgs.br/GIACOMO/arquivos/farmaco/chou-grossman-saffer-2002.pdf

The authors conclude that obesity rates have increased because of working women's significantly reduced time to shop and cook; and to the public health policy of reducing smoking rates. On page 32:

"In a sense, both findings underscore the price that must be paid to achieve goals that in general are favored by society...Whether public policies should be pursued that offset this ignored consequence of previous actions to discourage smoking and increase market opportunities [for women] depends on the costs and benefits of these policies."

Apparently, the folks who advocate banning toys from Happy Meals and posting calorie counts, driving up the cost of free market driven fast food establishments, believe that working women across the country are going to start shopping for fresh fruits and vegetables and make the same type of labor-intensive healthy meals from scratch that dedicated, full-time homemakers used to make. My personal belief is that rising fast food prices caused by government regulation will move the instant unhealthy meal market to the grocery store's frozen microwavable meal department (which is, parenthetically, the same general vicinity as the ice cream gallon freezer).

My brother quit smoking 9 years ago and put on 100 lbs. He hasn't been able to get rid of any of that added weight. Perhaps the government lowered the BMI guidelines so that we can blame the increase in obesity on this rather than by identifying their social welfare policies as the real causes?