09 July 2014

How many years does obesity shorten life?

Morbid obesity in adults significantly increases the risk of premature death from cancer and many other diseases, including heart disease, stroke, diabetes mellitus, as well as kidney and liver diseases. Specialists of the National Institute for Cancer Research of the USA, working under the guidance of Dr. Patricia Hartge, came to such conclusions based on the results of data analysis collected during 20 large studies involving residents of the USA, Sweden and Australia.

During the analysis, the authors classified the participants depending on the value of the body mass index (BMI), traditionally used as a measure of the amount of body fat and calculated as the ratio of body weight in kilograms to the square of height in centimeters.

  • Normal body weight: 18.5-24.9
  • Overweight: 25.0-29.9
  • Obesity of the 1st degree: 30.0-34.9
  • Obesity of the 2nd degree: 35.0-39.9
  • Obesity of the 3rd degree (pathological): 40.0 and above

After excluding participants with a history of smoking and a number of diseases from the sample, the researchers assessed the overall risk of premature death, as well as the risk of premature death associated with specific causes, for more than 9,500 people with grade 3 obesity and 304,000 people with normal weight.

The results showed that in the group with obesity of the 3rd degree, both the overall risk of premature death and the risk of premature death from major medical causes continuously increases as the body mass index increases.

Statistical analysis of the data showed that the increased mortality in this group was mainly due to heart diseases, malignant tumors and diabetes mellitus. The number of lost years of life in people with pathological obesity ranged from 6.5 years with a BMI of 40-44.9 to 13.7 years with a BMI of 55-59.9.

To obtain a visual comparison, the authors calculated that the number of years of life lost due to obesity of the 3rd degree corresponded to or exceeded the number of years of life lost by smokers compared to participants who had never smoked in the same study.

The authors note that the reliability of the results of the study is limited by the fact that the analysis mainly used data independently provided by the participants, and only the body mass index was used to assess the degree of obesity. However, the results obtained in any case indicate the need to develop more effective interventions aimed at combating obesity, which is one of the most serious medical problems of our time.

Article by Kitahara CM et al. Association between Class III Obesity (BMI of 40-59 kg/m2) and Mortality: A Pooled Analysis of 20 Prospective Studies published in the journal PLOS Medicine.

Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on materials from NIH/National Cancer Institute:
NCI study finds extreme obesity may shorten life expectancy up to 14 years.


Found a typo? Select it and press ctrl + enter Print version