Overweight and Obesity by Middle Age Are Associated with Shortened Lifespan

Summaries for Patients are a service provided by Annals to help patients better understand the complicated and often mystifying language of modern medicine.

Summaries for Patients are presented for informational purposes only. These summaries are not a substitute for advice from your own medical provider. If you have questions about this material, or need medical advice about your own health or situation, please contact your physician. The summaries may be reproduced for not-for-profit educational purposes only. Any other uses must be approved by the American College of Physicians-American Society of Internal Medicine.

The summary below is from the full report titled "Obesity in Adulthood and Its Consequences for Life Expectancy: A Life-Table Analysis." It is in the 7 January 2003 issue of Annals of Internal Medicine (volume 138, pages 24- 32). The authors are A Peeters, JJ Barendregt, F Willekens, JP Mackenbach, AAL Mamun, and L Bonneux, for the Netherlands Epidemiology and Demography Compression of Morbidity Research Group.

What is the problem and what is known about it so far?

Obesity is a serious and growing health problem. In 1990, about 56% of adult Americans were overweight and about 23% were obese. By 2000, 64% were overweight and 31% were obese. Overweight and obese people are more likely than normal-weight people to have chronic health problems such as diabetes, high blood pressure, and knee arthritis. They also die at younger ages.

Although Americans of all ages are increasingly overweight, many find that middle age is a particularly high-risk period for gaining weight. They may not realize that being overweight or obese by middle age is associated with shorter life expectancy. Furthermore, how much shorter life expectancy is among overweight and obese people compared to those of normal weight has not been clear.

Why did the researchers do this particular study?

To find out reductions in life expectancy associated with being overweight or obese at age 40 years.

Who was studied?

3457 men and women from Framingham, Massachusetts, who were middle-aged in 1950.

How was the study done?

Between 1948 and 1951, researchers asked Framingham residents about their health and lifestyles and measured their blood pressure and weight. They assessed weight using the body mass index (BMI). (BMI is a person's weight in kilograms divided by the square of his or her height in meters. People with BMIs of 25 to 30 mg/kg ² are overweight, and people with BMIs of 30 kg/m² or greater are obese.) The researchers followed Framingham residents regularly for many years. By 1990, most residents who had been middle-aged in 1950 had died. The researchers then compared how long the obese, overweight, and normal-weight people had lived.

What did the researchers find?

On average, adults who were obese at age 40 lived 6 to 7 years less than their normal-weight counterparts. Adults who were overweight and didn't smoke at age 40 lived about 3 years less than adults who were normal weight and didn't smoke. Adults who were obese and did smoke at age 40 lived 13 to 14 years less than those who were normal weight and didn't smoke.

What were the limitations of the study?

Weight was based on single measurements made around 1950. Descriptions of lost life expectancy are not clearly predictive of length of life that could be gained from obesity prevention treatment.

What are the implications of the study?

Obesity by 40 years of age is associated with significant shortening of life expectancy.