Saturday, April 30, 2011

Life expectancy vs Life with disability

I read a very interesting study this evening that is published in the online version of the journal Obesity.
Life Expectancy and Life Expectancy With Disability of Normal Weight, Overweight, and Obese Smokers and Nonsmokers in Europe

BY: Istvan M. Majer, Wilma J. Nusselder, Johan P. Mackenbach and Anton E. Kunst

The sample population included over 60,000 persons pretty evenly split between males and females.  The average age was between 44 and 50 (there were nine countries included).  The information on health status, disability, weight, education, smoking status and more was gathered through self report in a standardized survey.  The populations were tracked over time and the researchers could assess disability and death, but for the most part, this information is subject to several biases.  For instance, a person might give false information because they couldn't recall or because they did not want to tell the interviewer something that might make the interviewer "judge" them.  This information is certainly helpful and we can look at associations between factors and outcomes. It is also important to note that the information refers to groups of people, many times what is true for a population is not true for an individual.


In this study, the researchers compared normal weight non smokers (they were considered the baseline, or referent group), to normal weight, overweight and obese smokers and non smokers.  Former smokers were excluded from the analysis due to the many variances amongst former smokers (quit date, years smoked, amount smoked, etc).


Still they did gather smoking status, and the sample characteristics showed a wide range of population smoking rates that were disturbingly high.  Greece, Spain and Denmark were all over 35% for men, no country had below 25% (for men).


What this study shows is a relationship between being overweight and living longer and living longer with disability or disease.  Smoking did not provide more disability - nor less, but it shortened the life expectancy in total.


The authors felt that smoking cessation would increase life and losing weight would increase years of life without disability. In other words, stop smoking and live longer, lose weight (or maintain a normal weight) and live better. 

The authors did not note a difference between men and women, but I saw a definite difference in disability years in the chart that they provided.  I am actually going to see if I can post it in here. 

It shows four graphs.  The two on top are for men (non smoker v smoker) and the two on the bottom are for women. [we must remember that these are pooling of data from 9 countries which are not necessarily similar]

They also compare persons by education, but I feel like the more telling factor would have been income.  In this chart, and in the sample, women live several years longer than men, but they also have more years of living with disability.  For instance, low educated obese women had about 20 years LWD (living with disability) and men in the same category have 14.7.  In every block, the women have more years of disability.  The authors also calculated percent of life lived with disability - that was interesting too.  Again, the differences are not between smokers and non smokers(for percent of life spent disabled), but between men and women.  I am actually very curious why the graphics point this out but the scientists do not emphasize it.  You know what that means - I will have to email the lead author (okay I am back - email sent :)). 

 I do not say this to be fickle, but because for instance, in the obese category for non smokers, men have 19% of disability years and women have 28% - it is substantial.  If it is not significant - well there are not statistics to make inferences- thus I wrote to ask.

Take home message - don't smoke and do lose weight because those extra ten years won't mean near as much if you cannot do anything.  :)

Okay I got the chart in  -  for education purposes.  Note that the bottom half is disease free life expectancy and the top is life with disability.  Do you see the differences between the various groups?


From the study published in Obesity 3-17-2011 Majer, et al.


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