Fasting total homocysteine (tHcy) concentration and mortality in older Mexican Americans.

OBJECTIVES

This study examines the association between tHcy on cardiovascular and noncardiovascular mortality.

DESIGN

Longitudinal study of 1,633 Mexican Americans age>60 years recruited in 1998.

SETTING

Sacramento, California.

MEASUREMENTS

Cox proportional models were used to estimate the effects of tHcy on mortality rate in the total sample and in a subgroup of subjects without a history of cardiovascular disease at baseline.

RESULTS

About half of the cohort was born in Mexico. Among Mexican-born participants, high tHcy (>11.0 micromol/L) was associated with a higher rate of cardiovascular mortality compared to those with low tHcy concentration<or=11.0 micromol/L (HR=2.74 95%CI [1.61, 4.66]). Among the US-born, higher tHcy predicted cardiovascular mortality (HR=1.74 95%CI [1.08, 2.82]). When the effects of tHcy were evaluated in the subgroup without self-report of cardiovascular disease at baseline, the effect of high tHcy on mortality remained only among the Mexican-born. These differences did not appear to be influenced by demographic, lifestyle factors, chronic diseases or biological markers at baseline. No significant associations between tHcy and noncardiovascular mortality were observed for either group.

CONCLUSIONS

The effect of tHcy on cardiovascular mortality is nearly 40% stronger among the immigrant group. tHcy might be an early marker of subclinical vascular pathology amongst the Mexican-born group, despite their apparently healthy profile at baseline.