Fat mass, fat-free mass linked to mortality in Asians

Asians with extremely high or low fat mass index (FMI) and fat-free mass index (FFMI) are at increased risk of mortality, suggests a study. However, the associations of FMI and FFMI with the mortality risk differ across subgroups and causes of death.

A total of 422,430 participants (51.9 percent women) from the Taiwan MJ Cohort, with a mean follow-up of 9 years, were included in this study, which sought to explore the relationship of FMI and FFMI with all-cause mortality and cause-specific mortality in the Chinese population.

The highest (Q5) and lowest (Q1) quintiles of FMI and FFMI correlated with increased all-cause mortality. Individuals in Q1 and Q5 of FMI had 32-percent (hazard ratio [HR], 1.32, 95 percent confidence interval [CI], 1.24‒1.40) and 13-percent (HR, 1.13, 95 percent CI, 1.06‒1.20) increased mortality risk, respectively, compared with those in the third quintile (Q3).

Likewise, participants in Q1 (HR, 1.14, 95 percent CI, 1.06‒1.23) and Q5 (HR, 1.16, 95 percent CI, 1.10‒1.23) of FFMI had increased risk compared with those in Q3. Additionally, both FMI and FFMI exhibited a J-shaped association with all-cause mortality in the restricted cubic spline models.

Of note, individuals in Q5 of FFMI had a 28-percent lower risk of respiratory disease (HR, 0.72, 95 percent CI, 0.58‒0.89).

“The mortality risk increases in those with excessively high or low FMI and FFMI, yet the associations between FMI, FFMI, and the risk of death varied across subgroups and causes of death,” the authors said.