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 th e 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 in dividuals, 65 to 84 years of age, free-living or institutionalized in the I mpruneta Municipality, area of Florence, Italy. MEASUREMENTS: Conventional vascular risk factors and vascular diseases defi ned following a two-step procedure (screening phase and confirmation on pos itives) using standard and validated criteria. Lp(a) levels determined by a n ELISA method. RESULTS: No association was observed between elevated Lp(a) levels alone an d any of the examined vascular diseases (stroke, myocardial infarction, ang ina, and intermittent claudication). In contrast, examining the interaction s between elevated Lp(a) and conventional vascular risk factors, when eleva ted 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 i nterval [CI]: 1.27-13.40) was observed, much higher than that expected base d on the additive effect of smoking and elevated Lp(a) alone, CONCLUSIONS: With the cautions due to the cross-sectional design of the stu dy and the limited statistical power, these results suggest a possible syne rgistic effect between elevated Lp(a) levels and other pro-atherogenic fact ors such as smoking on the risk of vascular diseases in older individuals.