Plasma total homocysteine and cardiovascular and noncardiovascular mortality: the Hordaland Homocysteine Study.

BACKGROUND: Few population-based studies have assessed relations between plasma or serum total homocysteine (tHcy) and all-cause mortality. OBJECTIVE: Our goal was to study associations between plasma tHcy and all-cause, cardiovascular, and noncardiovascular mortality. DESIGN: This was a prospective cohort study of 2127 men and 2639 women aged 65-67 y in 1992-1993 when they were recruited as part of a population-based national cardiovascular screening program carried out in Hordaland County, Norway. RESULTS: During a median of 4.1 y of follow-up, 162 men and 97 women died. A strong relation was found between plasma tHcy and all-cause mortality. The association was highly significant for noncardiovascular and for cardiovascular causes of death. In a comparison of individuals having tHcy concentrations of 9.0-11.9, 12.0-14.9, 15.0-19.9, or > or = 20 micromol/L with individuals having a tHcy concentration < 9 micromol/L, adjusted mortality ratios were 1.4, 1.9, 2.3, and 3.6 (P for trend = 0.0002) for noncardiovascular and 1.3, 2.1, 2.6, and 3.5 (P for trend = 0.0002) for cardiovascular causes of death. A tHcy increment of 5 micromol/L was associated with a 49% (95% CI: 28%, 72%) increase in all-cause mortality, a 50% (95% CI: 21%, 85%) increase in cardiovascular mortality (121 deaths), a 26% (95% CI: -2%, 63%) increase in cancer mortality (103 deaths), and a 104% (95% CI: 44%, 289%) increase in noncancer, noncardiovascular mortality (33 deaths). CONCLUSION: Plasma tHcy is a strong predictor of both cardiovascular and noncardiovascular mortality in a general population of 65-72-y-olds. These results should encourage studies of tHcy in a wider perspective than one confined to cardiovascular disease.