Homoarginine and mortality in an older population: the Hoorn study

Background Homoarginine is an amino acid that may be involved in nitric oxide and energy metabolism. Previous studies in patient populations showed that low homoarginine levels indicate an increased risk of mortality and cardiovascular disease. We evaluated whether low plasma levels of homoarginine are associated with elevated, overall and cause-specific mortality. Materials and methods The Hoorn study is a population-based study among older men and women. We calculated Cox proportional hazard ratios (HRs) for overall and cause-specific mortality according to sex-specific homoarginine quartiles. Results We included 606 study participants (513% women; 700 66 years). Homoarginine concentrations were higher in men (163 051 lM), compared with women (130 044 lM; P < 0001). After a median follow-up time of 78 years, 112 study participants died, including 31 deaths due to cardiovascular diseases and 30 due to cancer. Associations between homoarginine levels and mortality showed a threshold effect with a significant risk increase from the second to the first quartile. Compared with the upper three quartiles, the age-, sex- and BMI-adjusted HR (with 95% CI) in the first quartile was 226 (152–332) for overall mortality, 420 (203–869) for cardiovascular mortality and 125 (055–285) for cancer mortality. These associations remained materially unchanged after multivariate adjustments.