Lipoprotein(a) serum levels and vascular diseases in an older Caucasian population cohort

OBJECTIVE: To investigate elevated lipoprotein(a) [Lp(a)] levels as a risk factor for stroke, myocardial infarction, angina, intermittent claudication, and combination of the above in a cohort of unselected older individuals. DESIGN: Population cohort from one of the eight centers participating in the Italian Longitudinal Study on Aging (ILSA). SETTING: General community. PARTICIPANTS: A subsample of 446 subjects (M/F: 231/215, mean age: 74.5 +/- 5.7 years) of the original, randomly selected, population cohort of 704 individuals, 65 to 84 years of age, free-living or institutionalized in the Impruneta Municipality, area of Florence, Italy. MEASUREMENTS: Conventional vascular risk factors and vascular diseases defined following a two-step procedure (screening phase and confirmation on positives) using standard and validated criteria. Lp(a) levels determined by an ELISA method. RESULTS: No association was observed between elevated Lp(a) levels alone and any of the examined vascular diseases (stroke, myocardial infarction, angina, and intermittent claudication). In contrast, examining the interactions between elevated Lp(a) and conventional vascular risk factors, when elevated Lp(a) was combined with a history of smoking, a marked increase in the risk of vascular diseases combined (odds ratio [OR]: 4.12; 95% confidence interval [CI]: 1.27-13.40) was observed, much higher than that expected based on the additive effect of smoking and elevated Lp(a) alone, CONCLUSIONS: With the cautions due to the cross-sectional design of the study and the limited statistical power, these results suggest a possible synergistic effect between elevated Lp(a) levels and other pro-atherogenic factors such as smoking on the risk of vascular diseases in older individuals