Effects of overweight and smoking in late adolescence on mortality
The interesting a new finding in this study was that being obese at age 19 conferred excess risks of premature death that were similar in magnitude to those from smoking. This was new because some prior studies had not found very large or clear effects on excess mortality from being overweight.
In fact the excess risks from being overweight (as opposed to obese) were not so great in this study (comparable but less than risks due to light smoking). Unfortunately the smoking risks were not broken down in detail by consumption. Other studies have shown a marked dose-response effect with much greater health effects for much greater cigarette consumption.
We need to remember that this study relied upon a single measurement at age 19 and was not able to take into account that people change their habits over the years. The study also didn’t take into account the fact that many Swedish men switch from smoking to use of smokeless tobacco, and that the smokeless tobacco (like smoking) may have influenced body weight and some health risks. So these factors (such as changes in habits over time) would likely add “noise” to the data and it is impressive that despite these limitations fairly clear results emerged.
So what are the lessons here? Perhaps the main new lesson is that obesity in late adolescence does predict significantly increased risks of premature death in middle age, and therefore needs to be taken seriously as a public health problem. But it remains clear that smoking is extremely bad for health and that someone who is both obese and a smoker has 5 times the risk of death in middle age of a normal-weight non-smoker.
What this does NOT mean is that if you are a smoker there is no point in quitting because the health benefit will be offset by weight gain. The typical smoker gains about 5-7 lbs in the year after quitting smoking. You would have to gain around 50 pounds to come close to offsetting the health benefit from quitting.
So the message is: quit smoking, eat healthy, and exercise more.
I recommend this blog for advice on healthy eating: http://www.healthline.com/blogs/diet_nutrition/
And this one for advice on healthy exercise: http://www.healthline.com/blogs/exercise_fitness/
This post contains some tips and further links on getting ready to quit smoking: http://www.healthline.com/blogs/smoking_cessation/2008/12/get-ready-for-smoke-free-2009.html
You can read the full research report from the BMJ at: http://www.bmj.com/cgi/content/full/338/feb24_2/b496?view=long&pmid=19244221