Extreme Obesity May Lower Life Expectancy by almost 14 years

Extremely obese adults are at a higher risk of premature death from cancer, heart diseases, stroke, diabetes, kidney and liver diseases, a new study reveals.

Obesity is known to take a toll on the human body and also puts a person at an increased risk of serious health conditions. An adult is considered obese when their body mass index (BMI) is 30 or greater. In the U.S., nearly 70 percent of the adults are either overweight or obese. And, this has overtaken smoking as a leading cause of premature death and illness.

In a new study, researchers from the National Cancer Institute, analyzed data retrieved from 20 large studies that included people from three countries and found that those belonging to class III obesity i.e. extreme obesity had a drastic reduction in life expectancy.

"While once a relatively uncommon condition, the prevalence of class III, or extreme, obesity is on the rise. In the United States, for example, six percent of adults are now classified as extremely obese, which, for a person of average height, is more than 100 pounds over the recommended range for normal weight," said Cari Kitahara, Ph.D., Division of Cancer Epidemiology and Genetics, NCI, and lead author of the study. "Prior to our study, little had been known about the risk of premature death associated with extreme obesity."

The study participants were divided according to their body mass index (BMI), measure of total body fat and dividing a person's body weight by their height in meters squared. The BMI classifications were 'Normal weight: 18.5-24.9', 'Overweight: 25.0-29.9', 'Class I Obesity: 30.0-34.9', 'Class II Obesity: 35.0-39.9', 'Class III Obesity: 40.0 or higher'.

The risk of premature death was evaluated after excluding those who smoked or who had a history of certain diseases. They evaluated the risk of early death in more than 9,500 individuals of Class III obese and 304,000 others of normal weight.

They noticed that the risk of premature death increased with increasing BMI within the class III obesity group.

"Years of life lost ranged from 6.5 years for participants with a BMI of 40-44.9 to 13.7 years for a BMI of 55-59.9. The number of years of life lost for class III obesity was equal or higher than that of current (versus never) cigarette smokers among normal-weight participants in the same study," researchers noted.

The study emphasizes on the need for effective interventions in order to combat the growing public health concern of extreme obesity. It is seen that class III obesity is on the rise worldwide and may soon be recognized as a major cause of early death.

The finding was documented in PLOS Medicine.