Overweight Status At Midlife Associated With Higher Morbidity Burden

Sadiya S. Khan, MD, MSc

New findings indicate overweight status in middle life, compared to normal body mass index (BMI), was associated with higher cumulative burden of morbidity and greater proportion of life lived with morbidity in the context of similar longevity.

Although there is abundant evidence that obesity is associated with higher all-cause and cardiovascular mortality, population-level prevention efforts have been ineffective and projections estimate that nearly 1 in 2 US adults will be obese by 2030.

A team of investigators, led by Sadiya S. Khan, MD, MSc, Division of Cardiology, Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, noted “the potential of a survival advantage for overweight status, if one exists, may come at the cost of a greater proportion of life lived with morbidity.”

A study sample was derived from the Chicago Heart Association Detection Project in Industry (CHA) cohort, which recruited men and women 18 years and older between 1967 and 1973 (n = 38,665). Participants were followed up with for more than 40 years since baseline in-person examination linked with Medicare follow-up between January 1985 - December 2015.

For the primary outcome, investigators quantified morbidity burden with the Gagne combined comorbidity score ranging from -2 to 26, with a higher score associated with higher mortality.

Then, investigators examined the mean overall survival time (total longevity) and differences in health care costs across BMI categories compared with normal BMI.

From a total of 29,621 participants, the mean age was 40 years and 57.1% were men, 42.9% were women, and 9.1% were Black. Additional data show 46.0% had normal BMI, 39.6% were overweight, and 11.9% had classes I and II obesity at baseline.

The cumulative morbidity burden based on the Gagne score assessed per year was significantly higher, among those who were overweight (7.22 morbidity-years), had classes I and II obesity (9.80 morbidity-years) and had class III obesity (10.32 morbidity-years), compared with those with a normal BMI (6.10 morbidity-years) in midlife (P <.001).

Throughout the follow-up, 13,932 participants (47.0%) died with a similar mean age at death among those overweight (82.1 years [95% CI, 81.9 - 82.2 years]) and those with normal BMI (82.3 years [95% CI, 82.1 - 82.5 years]).

Data show a younger mean age at death in the classes I and II obesity (80.8 years [95% CI, 80.5 - 81.1 years]) and class III obesity (77.7 years [95% CI, 76.2 - 79.1 years]).

Further, investigators observed the proportion of life-years lived in older adulthood with a Gagne score of ≥1 was 0.38% in those with a normal BMI, 0.41% in those with overweight, and 0.43% in those with obesity.

As for cost, the cumulative median per-person health care cost in older adulthood were significantly higher among overweight participants ($12,390 [95% CI, $10,427 - $14,354) and those with classes I and II obesity ($23,396 [95% CI, $18,474 - $28,319]).

“The greater proportion of life lived with morbidity translated to higher adjusted cumulative and mean annual health care expenditures during older adulthood, which will have substantial consequences for health care costs as the aging population intersects with the obesity epidemic,” wrote Khan.

The study, “Association of Body Mass Index in Midlife With Morbidity Burden in Older Adulthood and Longevity,” was published in JAMA Network Open.