Study of liver function in healthy elderly subjects using the 13C-methacetin breath test

Abstract

Background: The issue of whether or not liver function is compromised in the healthy elderly population remains unsolved. Aim: To investigate the putative age-related modifications of hepatic function using the 13C-methacetin breath test. Because endogenous CO2 production changes with age, motor activity and nutrition, a different form of processing the results was investigated. Patients and methods: Twenty-nine elderly subjects (mean age, 79.8 ± 7.9 years: female/male ratio, 17/12) and 28 adult subjects (mean age, 40.6 ± 12.3 years; female/male ratio, 13/15) underwent 13C-methacetin breath test and trans-abdominal echosonography with Doppler pulsed wave analysis of the coeliac axis and portal vein. Results: Although the 13CO2 peak occurred within 15-30 min in both elderly and adult subjects, it was significantly decreased in the former (30.66% ± 9.2% vs. 38.33% ± 6.05%; P < 0.001), as was the cumulative excretion (33.07% ± 7.06% vs. 39.81% ± 5.68%; P < 0.001). When correcting for the effects of CO2 excretion by age, the age-related modification of the cumulative dose became more evident (elderly group 30.15% ± 6.46% vs. adult group 37.97% ± 5.92%; P < 0.0001). The elderly group also showed an increase in the intra-hepatic resistance index using Doppler pulsed wave analysis, which inversely correlated with the results of the breath test. Conclusions: Hepatic function is not well preserved in healthy humans throughout life and may be due to an increase in vascular resistance.