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 (>11.0μmol/L) was associated with a higher rate of cardiovascular mortality compared to those with low tHcy concentration ≤11.0μmol/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.