Key Takeaways
- A global study showed that BMI-associated gaps in blood pressure and cholesterol have diminished from 1990 to 2024.
- With more medications being used, older people with obesity were metabolically similar to, and in some countries even lower risk than, people with a normal BMI.
- Young adults with obesity remain metabolically higher risk, however, and should be a focus of prevention and treatment, some say.
For middle-age and older people, obesity was no longer associated with the same cardiovascular burden as before -- though it was a different story for young adults, according to a large longitudinal multi-country study.
Across industrialized countries, mean non-HDL cholesterol and systolic blood pressure (BP) declined over time from 1990 to 2024. People in the obesity and overweight body mass index (BMI) ranges increasingly approached their normal-BMI peers in:
- Non-HDL cholesterol: pooled estimate of change in difference -0.05 mmol/L per decade for women and -0.07 mmol/L per decade for men
- Systolic BP: -0.7 mmHg per decade for women and -0.6 mmHg per decade for men
In fact, with more older adults using BP- and lipid-lowering medications, people older than 40 years achieved a convergence of these risk factors between individuals with obesity and normal BMI.
"As a result of these trends, in England, the U.S.A., Thailand, South Korea, and Japan, older people with obesity often became indistinguishable from, or better off than, those with normal BMI in terms of non-HDL cholesterol and systolic BP," wrote Majid Ezzati, PhD, of Imperial College London, and colleagues in the NCD Risk Factor Collaboration in The Lancet.
The bad news: for people younger than 40 years, there has been little change in lipid and BP gaps between those with obesity or overweight and those with normal BMI. "Young adults with obesity remain metabolically at higher risk than their counterparts with normal weight," the authors reported.
This may be related to the finding that young adults were rarely treated for high cholesterol or BP, regardless of their BMI.
"The low treatment rates in younger adults might be because treatment decisions at least partly rely on calculated absolute risk, which increases with age. Additionally, healthcare use or medication adherence might be lower in young adults, either because of their actual or perceived need for care or because they are less able to do so as they transition into work," the investigators surmised.
This could indicate a missed opportunity for preventive cardiology, which has otherwise "advanced substantially, with broader screening, earlier detection, and expanding use of antihypertensive and lipid-lowering therapies," according to Yuan Lu, ScD, of the Yale School of Medicine in New Haven, Connecticut, in an accompanying editorial.
Notwithstanding the present report, and the availability of GLP-1 drugs for weight loss, Lu suggested that obesity is still a major public health problem for both young and old.
"Obesity remains associated with diabetes, chronic kidney disease, fatty liver disease, cancer, sleep disorders, musculoskeletal conditions, and systemic inflammation, many of which are not captured by blood pressure or non-HDL cholesterol alone," she noted. "Therefore, the findings should not be interpreted as evidence that obesity has become benign. Rather, the findings suggest that some cardiovascular consequences of obesity are increasingly being attenuated through medical management."
The NCD Risk Factor Collaboration analyzed data from 110 national health surveys from seven countries: Japan, South Korea, Taiwan, Thailand, Finland, England, and the U.S.
Altogether, there were 978,425 participants age 20-79 years sampled.
Obesity was most prevalent in the U.S. (range 35.7-47.2% in 2024 across sex-age groups) and lowest in Japan (3.2-9.6%). The prevalence of obesity had risen in all seven countries and all age groups during the analysis period.
Ezzati and colleagues cautioned that the studies from different countries spanned different years, though all countries had at least one study in the 1990s and one after 2019. Other limitations included small sample sizes in specific study-sex-age-BMI subgroups (e.g., people with obesity in Asian countries) and the 60-80% response rates in these health surveys.
Additionally, several groups have also contended that obesity should not be defined by BMI in the first place.
By one estimate, 46.9% of the adult U.S. population, or roughly 126 million people ages 20 and older, are expected to have obesity by 2035.