The Obesity Paradox and Mortality in Older Adults: A Systematic Review

Abstract

“Obesity paradox” describes the counterintuitive finding that aged overweight and obese people with a particular disease may have better outcomes than their normal weight or underweight counterparts. This systematic review was performed to summarize the publications related to the obesity paradox in older adults, to gain an in-depth understanding of this phenomenon. PubMed©, Embase©, and Scopus© were used to perform literature search for all publications up to 20 March 2022. Studies were included if they reported data from older adults on the relation between BMI and mortality. The following article types were excluded from the study: reviews, editorials, correspondence, and case reports and case series. Publication year, study setting, medical condition, study design, sample size, age, and outcome(s) were extracted. This review has been registered with PROSPERO (no. CRD42021289015). Overall, 2226 studies were identified, of which 58 were included in this systematic review. In all, 20 of the 58 studies included in this review did not find any evidence of an obesity paradox. Of these 20 studies, 16 involved patients with no specific medical condition, 1 involved patients with chronic diseases, and 2 involved patients with type 2 diabetes mellitus. Seven out of the nine studies that looked at short-term mortality found evidence of the obesity paradox. Of the 28 studies that examined longer-term mortality, 15 found evidence of the obesity paradox. In the studies that were conducted in people with a particular medical condition (n = 24), the obesity paradox appeared in 18 cases. Our work supports the existence of an obesity paradox, especially when comorbidities or acute medical problems are present. These findings should help guide strategies for nutritional counselling in older populations.

Associations of diabesity with all‐cause and cardiovascular disease mortality: Findings from the Mexico City Prospective Study

“…Interestingly, in the no‐landmark analysis, individuals with normal weight and diabetes, as well as overweight individuals, showed the highest and lowest all‐cause mortality risk, respectively. This may be associated with the obesity paradox effect, which has a critical role in the incidence of a disease but a protective effect on those with a severe condition 22,23 . Yet, the mechanism behind this association remains unknown.…”

Mortality risk relationship using standard categorized BMI or knee-height based BMI – does the overweight/lower mortality paradox hold true?

“…Our results suggest that regardless of the BMI estimation method, overweight older men and women have a lower mortality risk, compared to normal/underweight individuals after adjusting for confounders, such as smoking, education, physical activity, residence, marital status, and comorbidities [ 6 ]. Irrespective of the method, obesity in men and women aged ≥ 80 years did not lead to an increased mortality risk.…”

“…In older adults, aged 65 years and over, the relationship between overweight, obesity and morbidity does not seem as clear, since earlier studies have reported that overweight and a low degree of obesity (BMI 30 - <35) have a certain protective effect against co-morbidity [ 3 , 4 ]. In addition, it has been suggested that neither overweight nor obesity increases the risk of all-cause mortality [ 5 ], particularly in the presence of comorbidities or acute medical problems [ 6 ].…”

The Humoral Response to SARS-CoV-2 Vaccine in Hemodialysis Patients Is Correlated with Nutritional Status

“…The association between malnutrition and ageing is well known in both CKD patients and non-CKD patients, due to shared etiologic factors, such as comorbid conditions associated with cachexia, physical inactivity, and frailty [ 25 , 27 ]. Indeed, the “obesity paradox” has been recognized in both dialysis and elderly populations, in whom overweight might be protective, paradoxically resulting in a better outcome [ 31 , 41 ].…”