Carantoni M, Zuliani G, Bader G, Palmieri E, Volpato S, Passaro A, Imbastaro T, Mezzetti A, Fellin R
2nd Department of Internal Medicine, University of Ferrara School of Medicine, Italy.
Nutr Metab Cardiovasc Dis. 1999 Oct;9(5):228-33.
Insulin resistance/hyperinsulinemia are often associated with aging and could play an important role in the development of glucose intolerance and dyslipidemia in the elderly. We investigated the relationship between plasma fasting insulin with total cholesterol (TC) and low density lipoprotein LDL cholesterol (LDL-C), triglycerides (TG), lipoprotein(a) [Lp(a)] levels apolipoprotein (a) [apo (a)] isoforms in 100 free-living "healthy" octo-nonagenarians.
Fasting insulin was positively correlated with TG, whereas a negative relation was found with TC and LDL-C (r = -0.29 and r = -0.28 respectively; p < 0.01), LDL-C/apo B, HDL-C and apo A-I levels. Fasting insulin was also inversely correlated with Lp(a) levels (r = -0.22; p < 0.03), whereas the latter were significantly related with TC and LDL-C (r = 0.30 and r = 0.31; p < 0.005), TG (r = 0.21; p < 0.05) and apo B (r = 0.26; p < 0.02). There was a negative relation between Lp(a) levels and apo(a) isoforms: the greater the apo(a) molecular weight, the lower the Lp(a) level (p < 0.0001). Fasting insulin increased with apo(a) size, though the difference in insulin levels among apo(a) isoforms was not significant (p = 0.4). Multiple regression analysis showed that fasting insulin was the best predictor of LDL-C (R2 = 0.14; p = 0.002) irrespective of age, gender, BMI, waist circumference and TG, while apo(a) isoform size, BMI and waist circumference were related with Lp(a) irrespective of TC and LDL-C, TG and apo B (R2 = 0.35 to 0.37; p < 0.0001).
These results suggest that fasting insulin levels significantly influence LDL-C metabolism in old age. Lp(a) levels seem to be very strongly related to genetic background, although an indirect relation with insulin through adiposity and/or other associated lipid abnormalities cannot be ruled out.
胰岛素抵抗/高胰岛素血症常与衰老相关，且可能在老年人糖耐量异常和血脂异常的发生发展中起重要作用。我们研究了100名自由生活的“健康”八九十岁老人的空腹血浆胰岛素与总胆固醇（TC）、低密度脂蛋白胆固醇（LDL-C）、甘油三酯（TG）、脂蛋白(a)[Lp(a)]水平及载脂蛋白(a)[apo(a)]异构体之间的关系。
空腹胰岛素与TG呈正相关，而与TC和LDL-C呈负相关（r分别为-0.29和-0.28；p<0.01），与LDL-C/apo B、高密度脂蛋白胆固醇（HDL-C）及载脂蛋白A-I水平也呈负相关。空腹胰岛素还与Lp(a)水平呈负相关（r=-0.22；p<0.03），而Lp(a)水平与TC和LDL-C显著相关（r分别为0.30和0.31；p<0.005），与TG（r=0.21；p<0.05）及apo B（r=0.26；p<0.02）也相关。Lp(a)水平与apo(a)异构体之间呈负相关：apo(a)分子量越大，Lp(a)水平越低（p<0.0001）。空腹胰岛素随apo(a)大小增加，尽管apo(a)异构体间胰岛素水平差异不显著（p=0.4）。多元回归分析显示，无论年龄、性别、体重指数（BMI）、腰围和TG如何，空腹胰岛素都是LDL-C的最佳预测指标（R2=0.14；p=0.002），而无论TC、LDL-C、TG和apo B如何，apo(a)异构体大小、BMI和腰围都与Lp(a)相关（R2=0.35至0.37；p<0.0001）。
这些结果表明，空腹胰岛素水平在老年时显著影响LDL-C代谢。Lp(a)水平似乎与遗传背景密切相关，尽管不能排除通过肥胖和/或其他相关脂质异常与胰岛素存在间接关系。
