Obesity increases the risk of heart attack over time

BOSTON — People who lived with obesity over a 10-year period had a 23 to 60 percent higher risk of experiencing a cardiovascular event than people with a relatively healthy body mass index (BMI), according to a new study presented at the Endocrine Society’s 2024 annual meeting in Boston.

Maintaining excess weight over a long period of time was associated with an increased risk of heart attack and stroke, whereas this was not the case with one-time increased BMI values.

“I see this as a glass half full,” said Dr. Alexander Turchin of Brigham and Women’s Hospital in Boston, who led the study. “If someone is overweight, there is an opportunity for them to reduce their subsequent risk of these cardiovascular events by reducing their weight.”

In this study, researchers used data from the Nurses’ Health Study and the Health Professionals Follow-Up Study to identify individuals who were found to have a BMI greater than 25 at least once between 1990 and 1999. Researchers calculated cumulative time spent overweight as the area under the curve of a BMI greater than 25 between 1990 and 1999 divided by 10.

They then followed these patients over the next two decades (2000-2020) to document cardiovascular events such as heart attack, stroke, and cardiovascular death. The researchers compared individuals with the highest obesity exposure over a decade (average annual BMI 30.6) with those with the lowest obesity exposure (average annual BMI 25.7).

The analysis included 109,259 women and 27,239 men. At the start of the study in 1990, participants were on average 48 years old and had a BMI of 27. Over 90% of participants were white, 5% had atherosclerotic cardiovascular disease, 2.6% had type 2 diabetes, and 47.7% were former smokers.

From 2000 to 2020, there were 12,048 (8.8%) cardiovascular events. After adjusting for demographic factors and comorbidities, researchers found that increased BMI at baseline was not associated with an increased risk of cardiovascular events; rather, being overweight increased the risk over time, especially in younger patients. For this study, researchers used participants’ age in 1990 as the baseline.

Among persons who have been obese for more than a decade, cardiovascular risk was highest in women aged less than 35 years in 1990 (hazard ratio (HR) 1.60; 95% CI 1.05–2.44), followed by men aged 35–50 years (HR 1.57; 95% CI 1.22–2.03), women aged 35–50 years (HR 1.27; 95% CI 1.01–1.58), and men aged 50–65 years (HR 1.23; 95% CI 1.02–1.48).

In this analysis, no data were available on men under 35 years of age. Interestingly, no increased risk was found in women over 50 years of age and men over 65 years of age living with obesity.

This result was not necessarily expected at the start of the study, but “other literature looking at the risks of long-term exposure to obesity for other outcomes such as cancer and diabetes has found similar effects: the effect is larger in younger individuals,” Turchin said.

The findings from this and similar studies are critical to “advancing patient treatment,” said Dr. Gitanjali Srivastava of Vanderbilt University Medical Center in Nashville, Tennessee, who moderated the research session.

“(The study) underscores that if we can reduce BMI in adults through early intervention, there is a chance of actually reducing cardiovascular risk and morbidity.”

The study was funded by Eli Lilly and the National Institutes of Health. Turchin reported receiving consulting fees from Novo Nordisk and Proteomics International and grants from Eli Lilly and Novo Nordisk. Srivastava consults for Novo Nordisk, Eli Lilly and Rhythm Pharmaceuticals. She reported receiving research grants from Eli Lilly.