Excess weight in middle-age shortens life expectancy by years

A new longitudinal study led by Northwestern University has found that middle-aged obese people die on average up to five years earlier than people with normal weight. In addition, obese or overweight people usually have more comorbidities and spend more years in poor health than thinner individuals, while having to deal with much higher health care costs across older adulthood.

In 2015, the researchers collected medical insurance data from 29,621 people over the age of 65. These individuals were recruited in the 1960s and 1970s for a long-term health study. By December 15 of 2015, approximately 13,000 of the participants had died. 

In order to analyze death rates by weight status, participants were split into groups based on their body mass index (BMI), which is calculated as weight in kilograms divided by height in meters squared. The scientists found that the larger the BMI someone had, the shorter their life expectancy was. For instance, severely obese people – those with BMIs over 30 – lived on average to 77.7, while moderately obese ones lived to 80.8. 

Although there was no significant difference in the mean age at death between individuals who were slightly overweight and those who had normal BMI (82.1 and 82.3 years), overweight people generally spent more of their adult years in poor health (7.22 years on average) compared to those with normal weight (6.10), and spent about $12,390 more money on health care than the thinner participants. Severely obese people were found to live more than a decade in ill health (10.2 years) and spend $23,396 in excess health care costs than persons with normal weight.

These findings provide evidence for the impact of obesity on the health and life of individuals, as well as on the cumulative costs to society of “the obesity epidemic.” 

“Resources and strategies are urgently needed at the individual and population level to address the growing public health challenge of excess weight in the context of an aging population,” concluded the authors.

The study is published in the journal JAMA Network Open.

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By Andrei Ionescu, Earth.com Staff Writer