Myeloperoxidase Levels and Mortality in Frail Community-Living Elderly Individuals

Background. Elevated systemic levels of myeloperoxidase (MPO) have been associated with unfavourable clinical outcomes. In the present study, we evaluate the impact of MPO, a pro-oxidant enzyme that catalyzes the initiation of lipid peroxidation and affects nitric oxide levels, on the risk of all-cause mortality in a large population of frail octogenarians and nonagenarians living in community. Methods. We analyzed data from the Aging and Longevity Study in the Sirente Geographic Area (iISIRENTE Study), a prospective cohort study that collected data on all individuals aged 80 years and older living in a inountain community (n = 363). The main outcome measure was the risk of death after 4 years of follow-up. Participants were divided into three groups based on MPO tertiles: lower tertile <= 61.5 mu g/L (n = 120), intermediate tertile 61.6-140.6 mu g/L. (n = 120), and higher tertile >= 140.7 mu g/L (n = 123). Results. A total of 150 deaths occurred during 4-years follow-up. The mean MPO level was 170.8 +/- 177.5 mu g/L among those who died compared with 135.4 +/- 142.4 mu g/L, among survivors (p = .03). Individuals in the highest M PO tertile had higher risk of mortality (40%[60/123]) compared with those in the lower tertile (26% [39/120]). After adjusting for potential confounders, compared with participants in the lower tertile. those in the higher tertile had a hazard ratio for mortality of 1.97 (95% confidence interval: 1.02-3.80). Conclusion. Our results obtained from a representative sample of very old and frail elderly individuals expand the knowledge that low levels of MPO are associated with better survival.