High plasma insulin and lipids profile in older individuals: The Italian longitudinal study on aging

Background. The inverse relationship of insulin level to high-density lipop rotein (HDL)-cholesterol and its positive association with hypertriglycerid emia has been demonstrated in several studies: however. the relationship of insulin to low-density lipoprotein (LDL)-cholesterol in elderly persons is not clear. This study investigates tile relationships of tasting plasma in sulin and selected metabolic and biological risk factors in an aged populat ion. Methods. The present study is based on a cross-sectional analysis of the da ta collected;It baseline of the Italian Longitudinal Study on Aging in 1992 on a random sample of 5632 Italians aged 65-84 years. Analyses were perfor med to compare the distribution of risk factors. such as blood level of lip ids, creatinine. albumin. fibrinogen, apolipoprotein A-1 and B, blood press ure, and body mass index (BMI). by quartiles of insulin, in both diabetic a nd nondiabetic participants. Results. Significantly higher levels of triglycerides and BMI and lower lev els of HDL-cholesterol were found in the upper quartile of insulin among no ndiabetic individuals. In men, we also found significantly higher level of systolic and diastolic blood pressure. The same trend for these variables, although not significant for HDL-cholesterol and blood pressure, was seen i n diabetic men. In diabetic women, total and LDL-cholesterol were significa ntly lower in the highest insulin quartile (p < .001). while no significant differences were seen in nondiabetic: women or in men. we also found highe r levels of white blood cells in the highest insulin quartile: of diabetic women. Conclusions. These results, apparently in disagreement with earlier reports on the clustering of cardiovasculur disease risk factors in hyperinsulinem ic individuals, could be due to the high frequency of chronic inflammation and tile high prevalence of urinary infections in older diabetic women.