J Nutr. 2021 Oct 2:nxab348. doi: 10.1093/jn/nxab348. Online ahead of print.
ABSTRACT
BACKGROUND: Observational studies have suggested that better protein nutritional status may contribute to prevention of frailty.
OBJECTIVE: To examine this hypothesis using a Mendelian randomization (MR) analysis.
METHODS: We conducted a two-sample MR study using GWAS summary statistics data of the UK Biobank. We applied genetically predicted serum albumin as a primary exposure measure and serum total protein as a secondary exposure measure. The outcome measure was the Rockwood frailty index (FI) based on 49 deficits from 356,432 individuals (53.3% of them were women, with a mean [SD] age of 56.7 [8.0] years. The association between serum protein measures and FI was mainly analyzed by the inverse variance weighted method.
RESULTS: A genetically predicted serum albumin level was not statistically significantly associated with FI in the full sample. However, in women, we observed a preventive association between genetically predicted serum albumin and FI (beta = -0.172 per g/L; 95% confidence interval = -0.336 to -0.007; P = 0.041). In the full sample, genetically predicted serum total protein was inversely associated with FI (beta = -0.153 per g/L; 95% confidence interval = -0.251 to -0.056; P = 0.002). In both women and men, higher serum total protein was significantly inversely associated with FI; regression coefficients were -0.148 per g/L (95% confidence interval = -0.287 to -0.009; P = 0.037) for women, -0.154 per g/L (95% confidence interval = -0.290 to -0.018; P = 0.027) for men.
CONCLUSIONS: The present MR study implies that better protein nutritional status modestly contributes to reducing the risk of frailty.
PMID:34601600 | DOI:10.1093/jn/nxab348
