Midlife obesity tied to increased prefrailty/frailty risk later in life

Using data from the ongoing population-based Tromsø study, baseline obesity was found to be associated with an increased risk of prefrailty/frailty in later years.

“[P]articipants with both high BMI and high waist circumference (WC), ie, general and abdominal obesity, especially for a long duration throughout their adulthood, were observed to have an increased likelihood of prefrailty/frailty,” said the researchers.

The odds of prefrailty/frailty were higher among those who were overweight at baseline (odds ratio [OR], 1.19), more so among those with obesity (OR, 2.41), compared with individuals with normal BMI. [BMJ Open 2023;13:e065707]

When looking at WC, the odds of prefrailty/frailty were also higher in participants with moderately high (OR, 1.57) or high (OR, 2.14) baseline WC than those with normal WC.

In the model that combined baseline WC and BMI profiles, the likelihood of prefrailty/frailty was higher among participants who had moderately high/high WC and were also overweight (OR, 1.48) or obese (OR, 3.11), compared with those with normal WC and BMI.

Maintaining optimal weight is key

“[These findings highlight] the importance of routinely assessing and maintaining optimal BMI and WC throughout adulthood to lower the risk of frailty in older age,” said the researchers.

One of the mechanisms that could explain for the link between obesity and prefrailty/frailty is the increased fat mass and lipid infiltration in muscle fibres that occurs with obesity which, in turn, reduces muscle strength and function. [J Am Med Dir Assoc 2014;15:240-250; Metabolism 2000;49:467-472] “When coupled with an age-related decline in muscle mass and strength, it causes ‘sarcopenic obesity’, which is linked to an increased risk of frailty and disability,” said the researchers.

This study comprised 4,509 community-dwelling adults aged ≥45 years in Tromsø, Norway who were participating in the Tromsø study* (n=2,169 [men] and 2,340 [women]). Mean age at baseline was 51.6 years. At follow up, 28.4 percent were prefrail and 1.1 percent were frail. The rest were classified as robust. Participants were followed for 21 years.

Despite the long follow up, lifestyle changes that transpired during this period were not accounted for, the researchers noted. “[This might have] impacted the development of prefrailty/frailty. So, the result of this study should be cautiously interpreted in light of these contextual issues.”

Also, with frailty and prefrailty being combined as one outcome, the results might have overestimated the relative risk. Repeated measures on frailty were also unavailable. “[C]aution should be applied while interpreting it as a risk,” they said.

“In the context where frailty is being recognized as a multidimensional construct encompassing not just physical but also cognitive, social, and psychological dimensions, the scope of our results focusing just on physical aspects of frailty might be limited,” they added.

“[Nonetheless,] the repeated measures on BMI and WC allowed us to account for changes in participants’ obesity status through the follow up period and gain a comprehensive understanding of the long-term effects of these exposures on the risk of frailty in later life,” the researchers noted.

Prefrailty is a multidimensional, transitional risk state that precedes frailty, which impairs quality of life and is associated with increased risk of falls, disability, hospitalization, and mortality. [Arch Gerontol Geriatr 2022;99:104586; Geriatr Nurs 2020;41:139-146; J Epidemiol Community Health 2016;70:716-721; Medicine 2017;45:15-18]

The study used Fried’s physical frailty criteria, which defined prefrailty as having one or two of five frailty components: weakness/low grip strength, slow walking speed, self-reported exhaustion, unintentional weight loss, and low physical activity. Having more than three of these components fell under the definition of frailty. [J Gerontol A Biol Sci Med Sci 2001;56:M146-156]

Based on these definitions, nearly half of community-dwelling people aged ≥50 years across 62 countries are estimated to be prefrail, while about 10 percent are frail. [Age Ageing 2021;50:96-104]