Being Overweight in Middle-age Reduces Life Span up to Five Years

Abundant evidence links obesity with adverse health consequences. However, controversies persist regarding whether overweight status compared with normal body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) is associated with longer survival and whether this occurs at the expense of greater long-term morbidity and health care expenditures.

In a cohort study of 29, 621 adults, being overweight and having classes I and II obesity compared with having a normal BMI at a mean age of 40 years were associated with a statistically significantly higher cumulative morbidity score and health care costs across older adulthood. Obese people were found to die on average up to 5 years earlier than healthy people. U.S. researchers examined insurance data from 30,000 people over decades, Even those who were moderately obese, nearly half of people in the United States, lost nearly two years of life. However, barely any difference in life expectancy was noted between people who were overweight (a BMI of between 25 and 29).

The researchers found that the more overweight someone was, the shorter their life expectancy. Severely obese people lived to 77.7 years, while those moderately obese lived to 80.8 years, and people who were overweight had an average life of 82.1 years. Researchers did not breakdown deaths by cause, but noted obese people are more likely to suffer from comorbidities. Being overweight causes inflammation and fatty deposits to develop in the arteries, putting strain on the heart and other vital organs. In addition, excess weight creates mechanical stress on the spine, hip, knees, ankles and feet. These orthopedic disorders often require surgery, physical therapy and sequelae that affect reduce the ability to exercise and contribute to further weight gain.

A key finding from this study was that being overweight in midlife was associated with higher cumulative burden of morbidity and greater proportion of life lived with morbidity. These findings translated to higher total health care expenditures in older adulthood for those who were overweight in midlife. The study found obese people paid an average cumulative total of $23,396 more in excess costs than a person with a healthy weight.

Special Notes:

1. It should be noted that the sample size used for this study came from a predominately white population which means the findings may have limited relevance to other groups
2. BMI is not used to diagnose obesity, as people who are very muscular can have a high BMI without being overweight. However, BMI is accepted as a useful indicator of weight and health for the general population.

Reference:

Sadiya S. Khan, MD, MSc; Amy E. Krefman, MS; Lihui Zhao, PhD; et al, Association of Body Mass Index in Midlife With Morbidity Burden in Older Adulthood and Longevity, JAMA Netw Open. 2022;5(3)