Increase seen in the BMI associated with lowest risk of death

The fat police are wrong again.

The media release is below.

###

Increase seen in the BMI associated with lowest risk of death

THE JAMA NETWORK JOURNALS

In a study appearing in the May 10, 2016 issue of JAMA, Børge G. Nordestgaard, M.D., D.M.Sc., of Copenhagen University Hospital, Herlev, Denmark and colleagues examined whether the body mass index (BMI) value that is associated with the lowest all-cause mortality has increased in the general population over a period of 3 decades.

Previous findings indicate that while average BMI has increased over time in most countries, the prevalence of cardiovascular risk factors may be decreasing among obese individuals. Thus, the BMI associated with lowest all-cause mortality may have changed over time. This study included three groups from the same general population enrolled at different times: the Copenhagen City Heart Study in 1976-1978 (n = 13,704) and 1991-1994 (n = 9,482) and the Copenhagen General Population Study in 2003-2013 (n = 97,362). All participants were followed up from inclusion in the studies to November 2014, emigration, or death, whichever came first.

The researchers found that the BMI value associated with the lowest all-cause mortality has increased by 3.3 over 3 decades from 1976-1978 to 2003-2013, from 23.7 to 27. In addition, the risk for all-cause mortality that was associated with BMI of 30 or greater vs BMI of 18.5 to 24.9 decreased from an adjusted hazard ratio of 1.3 to 1.0 over this 30-year period. “These latter findings were robust in analyses stratified by age, sex, smoking status, and history of cardiovascular disease or cancer.”

The authors write that an interesting finding in this study is that the optimal BMI in relation to mortality is placed in the overweight category in the most recent 2003-2013 cohort. “This finding was consistent in both the whole population sample (optimal BMI, 27), and in a subgroup of never-smokers without history of cardiovascular disease or cancer (optimal BMI, 26.1). If this finding is confirmed in other studies, it would indicate a need to revise the WHO categories presently used to define overweight, which are based on data from before the 1990s.”

Regarding the increase in the BMI value associated with the lowest all-cause mortality, the researchers write that “further investigation is needed to understand the reason for this change and its implications.”

###

6 thoughts on “Increase seen in the BMI associated with lowest risk of death”

  1. This is both not new and not surprising. The change in BMI classes (all classes were dropped by 2.5 units) in 1999 had no basis in clinical symptoms and simply had the effect (and maybe the intent) of bringing millions more people into the range where anti-obesity drugs and bariatric surgery could be recommended.

    It is further compounded by the continued increase in height observed even in western countries. Increased height results in a greater bone percentage and thus a higher BMI regardless of fat levels. That humans are still getting taller suggests that there is still an effect of nutrition reducing foetal and early development. Although the averages may be confounded by immigration from countries with poor nutrition, the fact that even in the West better nutrition is resulting in taller people really makes a mockery of the whole obesity hype.

  2. The concept of BMI is basically flawed.
    The definition of BMI is defined as weight divided by height squared.
    Weight is similar to a volume (the density of the body is roughly constant among individuals). BMI is therefore a volume divided by a surface (length squared). It is NOT a dimensionless number usable for comparisons !
    If you are 10 % taller and similar in body proportions, your weight will be 33 % higher (1.1 cubed) but your height squared only increases by 21 % (1.1 squared), and your BMI will increase by 10 %, although your body is exactly similar.
    Any college student can understand that, but the WHO seems populated with illiterates….

  3. Going by BMI alone, Rob Gronkowski and JJ Watt are obese, Watt morbidly so. The measure simply does not work for tall and broad-shouldered men.

    BMI is used because it’s easy to calculate based on easy to measure quantities, but only measures how much bigger you are than an “average healthy person”. Whether you are bigger because you are fatter, more muscular, or simply taller than that mythical average does not factor into the calculation.

  4. You’ve got an interesting point there, Francis (France)
    A tall person at 72″ and 180 lb. has a BMI of 24.4……
    A very tall guy at 79.2″ and 239.6 lb. has a BMI of 26.9…….
    A small person at 64.8″ and 131.2lb. has a BMI of 22.0….
    EVEN THOUGH all have exactly the same body proportions……
    So much for the relevance/usefulness of the famous BMI………..

Leave a Reply

Your email address will not be published.