Effect of age on the association of non-high-density-lipoprotein cholesterol and apolipoprotein B with cardiovascular mortality in a Mediterranean population with type 2 diabetes: the Casale Monferrato study

Measurement of plasma apolipoprotein (Apo) B may improve prediction of cardiovascular risk, as it provides a measure of the total number of atherogenic particles. The aim of this population-based study was to compare the association of non-HDL-cholesterol, ApoB and the ApoB:ApoA-I ratio with cardiovascular mortality in people with type 2 diabetes. We assessed the association of lipids, lipoprotein lipids and apolipoproteins with 11-year mortality from cardiovascular disease in the population-based cohort of the Casale Monferrato Study (1,565 people with diabetes; median age 68.9 years), and determined the effect of age (<= 70 and > 70 years) on these relationships. On the basis of 341 deaths from cardiovascular disease in 10,809 person-years of observation, there was a decreasing trend in risk adjusted for multiple factors across quartiles of total cholesterol, and LDL- and non-HDL-cholesterol in people aged > 70 years, but no trend in those aged <= 70 years. Age did not affect the protective effect of HDL-cholesterol. ApoB and ApoB:ApoA-I were associated with outcome in people in both age groups independently of non-HDL-cholesterol. After adjustment for multiple factors, including non-HDL-cholesterol, the hazard ratios for ApoB:ApoA-I in the upper vs lower quartile were 2.98 (95% CI 1.15-7.75; p for trend=0.009) for people aged <= 70 years and 1.94 (95% CI 1.20-3.13; p for trend=0.003) for those aged > 70 years. In this cohort of Mediterranean subjects with diabetes, ApoB and the ApoB:ApoA-I ratio were associated with cardiovascular disease mortality independently of non-HDL-cholesterol. Our findings support the recommendation that ApoB and ApoA-I should be measured routinely in all people with diabetes, particularly in the elderly.