Dynapenia-abdominal obesity and mortality risk, is independent effect obscured by age and frailty?:Birjand Longitudinal Aging Study (BLAS)

Background

Abdominal obesity and low muscle strength, known separately as risk factors for mortality, might have a synergistic effect when they co-occur. Dynapenic abdominal obesity (DAO) is a condition defined by the presence of both. However, DAO’s independent and combined impact on mortality remains under investigation.

Objective

The objective of the present study was to evaluate the association of dynapenia, abdominal obesity, and dynapenic abdominal obesity with all-cause mortality among community-dwelling older adults.

Methods

This is a longitudinal study with a 5-year follow-up conducted involving 1,354 community-dwelling older adults (≥ 65 years) of the Birjand Longitudinal Aging Study (BLAS). Abdominal obesity and dynapenia were respectively defined based on waist circumference (> 102 cm for men and > 88 cm for women) and grip strength (< 26 kg for men and < 16 kg for women). The sample was divided into four groups: non-dynapenic/non-abdominal obesity (ND/NAO), dynapenic/non-abdominal obesity (D/NAO), non-dynapenic/abdominal obesity (ND/AO), and dynapenic/abdominal obesity (D/AO). The outcome was all-cause mortality registered through four methods: 1- telephone interview with the family of the participants during September 2018 and February 2024, 2- hospital information systems, 3- death registry of the deputy of the Health of Birjand University of Medical Sciences 4- in a subject who died at home or out of hospital death registry was verified by a verbal autopsy performed by a clinician. Univariate and multiple Logistic regression models were used to estimate the risk of all-cause mortality as a function of dynapenia and abdominal obesity in competing events controlled by age, sex, multi-morbidity, and frailty.

Results

The mean age of the study participants was 69.77 ± 7.55 years, and about 703 (51.71%) were female. There was a statistical difference between the alive and the deceased groups in terms of sex, age, multimorbidity, and frailty. Mortality was statistically higher among dynapenic participants (P < 0.001). Unadjusted logistic regression analysis explored the relationship between D/NAO and mortality (OR = 2.18; CI 95% 1.25–3.78). In the adjusted models, no significant relationships were observed. Age and frailty had significant associations with mortality.

Conclusion

While our study found an association between dynapenia without abdominal obesity and increased mortality risk, factors like age and frailty might play a stronger role. These require further investigation to understand the independent effect of dynapenia on mortality fully.

Graphical abstract