Association between complementary anthropometric measures and all-cause mortality risk in adults: NHANES 2011-2016.

Background: Previous studies using a single obesity indicator cannot fully assess the association between body shape and mortality. We aimed to investigate the association between complementary anthropometric measures and all-cause mortality risk.

Methods: We combined National Health and Nutrition Examination Survey (NHANES) data from 2011 to 2016 with mortality data up to December 31, 2019. After excluding individuals with cancer at baseline, 13,728 participants were included. Cox regression models and restricted cubic spline (RCS) analyses were used to explore the association between general obesity, central obesity, and peripheral fat indicators and all-cause mortality risk.

Results: A total of 743 deaths occurred over a median follow-up of 5.83 years. In multivariable-adjusted Cox models, each 10-cm increase in waist circumference (WC), each 0.1-unit increase in waist-to-height ratio (WHtR), and each 0.01-unit increase in A Body Shape Index (ABSI) were associated with 20% (HR = 1.20; 95% CI: 1.02-1.41), 119% (2.19; 1.70-2.83), and 5% (1.05; 1.03-1.08) increased all-cause mortality risk, respectively. Conversely, each 1-cm increment in mid-arm circumference (MAC) was associated with 13% (HR = 0.87; 95% CI: 0.83-0.92) decreased mortality risk. Compared with normal group (body mass index (BMI): 18.5- <25.0), underweight (HR = 1.97; 95% CI: 1.12-3.45) and grade 3 obesity (1.37; 1.04-1.81) were at higher mortality risk. However, after further adjustment for WC, the effect of grade 3 obesity disappeared, and the RCS analyses for BMI changed from a J-shaped (P < 0.05 for non-linearity test) to a negative association (P < 0.01).

Conclusions: Underweight, grade 3 obesity, and central obesity were associated with an increased mortality risk, while peripheral fat was inversely associated with mortality.