A recent study has found that obesity in middle age may lead to a loss of up to five years in life expectancy. Researchers who tracked nearly 30,000 individuals over a period of up to 50 years discovered that those with a healthy weight lived an average of 82.3 years, while individuals classified as obese, defined as having a body mass index (BMI) over 40, lived an average of 77.7 years.
Even those who are severely obese – about a quarter of adults in the UK and nearly half of adults in the US – lost nearly two years of life. However, there was barely any difference in average life expectancy between individuals who are overweight (BMI between 25 and 29).
Researchers from Northwestern University in Chicago did not detail deaths by cause but noted that people suffering from severe obesity are more likely to develop associated diseases. Weight gain leads to inflammation and fat deposits in the arteries, resulting in strain on the heart and other vital organs. The new estimates are less extreme than previous studies, which suggested that severe obesity could reduce average life expectancy by a decade.
The team in Chicago collected medical insurance data from 29,621 individuals over the age of 65 in 2015. Participants were originally recruited for a long-term health study in the 1960s and 1970s. By December 2015, approximately 13,000 participants had died. To analyze mortality rates based on weight status, participants were then grouped according to BMI.
The researchers found that the more obese a person was, the shorter their life expectancy. Those who were severely obese lived to an average age of 77.7 years, while those who were moderately obese lived to 80.8 years. The average age for individuals classified as overweight was 82.1 years, according to the Daily Mail.
