Among adults with type 2 diabetes (T2D) older than 65 years, a body mass index (BMI) in the moderate overweight category (26-28) appears to offer better protection from cardiovascular death than does a BMI in the “normal” range, new data suggested.
On the other hand, the study findings also suggest that the “normal” range of 23-25 is optimal for middle-aged adults with T2D.
The findings reflect a previously demonstrated phenomenon called the “obesity paradox,” in which older people with overweight may have better outcomes than leaner people due to factors such as bone loss, frailty, and nutritional deficits, study lead author Shaoyong Xu, of Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, China, told this news organization.
“In this era of population growth and aging, the question arises as to whether obesity or overweight can be beneficial in improving survival rates for older individuals with diabetes. This topic holds significant relevance due to the potential implications it has on weight management strategies for older adults. If overweight does not pose an increased risk of cardiovascular mortality, it may suggest that older individuals are not necessarily required to strive for weight loss to achieve so-called normal values.”
Moreover, Dr. Xu added, “inappropriate weight loss and being underweight could potentially elevate the risk of cardiovascular events, myocardial infarction, cerebral infarction, and all-cause mortality.”
Thus, he said, “while there are general guidelines recommending a BMI below 25, our findings suggest that personalized BMI targets may be more beneficial, particularly for different age groups and individuals with specific health conditions.”
Asked to comment, Ian J. Neeland, MD, director of cardiovascular prevention, University Hospitals Harrington Heart & Vascular Institute, Case Western Reserve University, Cleveland, Ohio, pointed out that older people who are underweight or in lower weight categories may be more likely to smoke or have undiagnosed cancer, or that “their BMI is not so much reflective of fat mass as of low muscle mass, or sarcopenia, and that is definitely a risk factor for adverse outcomes and risks. ... And those who have slightly higher BMIs may be maintaining muscle mass, even though they’re older, and therefore they have less risk.”
However, Dr. Neeland disagreed with the authors’ conclusions regarding “optimal” BMI. “Just because you have different risk categories based on BMI doesn’t mean that’s ‘optimal’ BMI. The way I would interpret this paper is that there’s an association of mildly overweight with better outcomes in adults who are over 65 with type 2 diabetes. We need to try to understand the mechanisms underlying that observation.”
Dr. Neeland advised that for an older person with T2D who has low muscle mass and frailty, “I wouldn’t recommend necessarily targeted weight loss in that person. But I would potentially recommend weight loss in addition to resistance training, muscle building, and endurance training, and therefore reducing fat mass. The goal would be not so much weight loss but reduction of body fat and maintaining and improving muscle health.”
U-Shaped Relationship Found Between Age, BMI, and Cardiovascular Disease (CVD) Risk
The data come from the UK Biobank, a population-based prospective cohort study of adults in the United Kingdom. A total of 22,874 participants with baseline T2D were included in the current study. Baseline surveys were conducted between 2006 and 2010, and follow-up was a median of 12.52 years. During that time, 891 people died of CVD.
Hazard ratios were adjusted for baseline variables including age, sex, smoking history, alcohol consumption, level of physical exercise, and history of CVDs.
Compared with people with BMI a < 25 in the group who were aged 65 years or younger, those with a BMI of 25.0-29.9 had a 13% higher risk for cardiovascular death. However, among those older than 65 years, a BMI between 25.0 and 29.9 was associated with an 18% lower risk.
A U-shaped relationship was found between BMI and the risk for cardiovascular death, with an optimal BMI cutoff of 24.0 in the under-65 group and a 27.0 cutoff in the older group. Ranges of 23.0-25.0 in the under-65 group and 26.0-28 in the older group were associated with the lowest cardiovascular risk.
In contrast, there was a linear relationship between both waist circumference and waist-to-height ratio and the risk for cardiovascular death, making those more direct measures of adiposity, Dr. Xu told this news organization.
“For clinicians, our data underscores the importance of considering age when assessing BMI targets for cardiovascular health. Personalized treatment plans that account for age-specific BMI cutoffs and other risk factors may enhance patient outcomes and reduce CVD mortality,” Dr. Xu said.
However, he added, “while these findings suggest an optimal BMI range, it is crucial to acknowledge that these cutoff points may vary based on gender, race, and other factors. Our future studies will validate these findings in different populations and attempt to explain the mechanism by which the optimal nodal values exist in people with diabetes at different ages.”
Dr. Neeland cautioned, “I think more work needs to be done in terms of not just identifying the risk differences but understanding why and how to better risk stratify individuals and do personalized medicine. I think that’s important, but you have to have good data to support the strategies you’re going to use. These data are observational, and they’re a good start, but they wouldn’t directly impact practice at this point.”
The data will be presented at the European Congress on Obesity taking place May 12-15 in Venice, Italy.
The authors declared no competing interests. Study funding came from several sources, including the Young Talents Project of Hubei Provincial Health Commission, China, Hubei Provincial Natural Science Foundation of China, the Science and Technology Research Key Project of the Education Department of Hubei Province China, and the Sanuo Diabetes Charity Foundation, China, and the Xiangyang Science and Technology Plan Project, China. Dr. Neeland is a speaker and/or consultant for Boehringer Ingelheim, Novo Nordisk, Bayer, and Eli Lilly and Company.
A version of this article appeared on Medscape.com.