LIPID RISK FACTORS IN ELDERLY SUBJECTS WITH NORMAL OR HIGH GLYCEMIC LEVELS OR WITH TYPE 2 DIABETES

M. Noale1, S. Maggi1, F. Limongi1, G. Romanato1, G. Crepaldi1

1CNR, Institute of Neuroscience, Padua Section (Italy)

Objectives: In accordance with the criteria of the American Diabetes Association, the World Health Organization defined the differentiation between subjects with Type 2 diabetes (T2D), subjects with normal fasting glucose (NFG) and subjects with impaired fasting glucose (IFG). Subjects with T2D are generally characterized also by hypertiglyceridemia and low levels of HDL cholesterol. There is less agreement about LDL cholesterol because some studies have found normal levels, others higher levels, and others levels that are lower than those in non diabetic controls. The aim of this work is to explore the relation between lipids in a representative sample of Italian subjects stratified on the basis of belonging to the NFG, IFG or T2D groups and to evaluate their capacity to predict fatal events.

Methods: The analyses are based on data collected by the Italian Longitudinal Study on Aging (ILSA) which, between the years of 1992 and 2000, enrolled 5,632 subjects aged 65-84 years, residents in eight cities of Italy. In the analyses presented here 2,422 of these subjects were considered. The association between groups of subjects (NFG, IFG, T2D) and clinical and demographic features were analysed using Mantel-Hanszel χ2 test for trend (categorical variables) and Jonckheere-Terpstra test (continuous variables). Factor analyses for males and females separated was developed using the principal component method. Variables included in the factor analysis were triglycerides, total cholesterol, HDL, APO A1, APO B, insulin, HOMA IR, fasting glucose, body mass index and abdominal circumference. Varimax rotations were used to interpret the factors, and variables with a factor weight ≥ |0.45| were considered in the interpretation of the factor.

Data on mortality collected between baseline and 1996 follow-up were considered, and the factor scores calculated at baseline were utilized in Cox models to determine the death risk attributable to each factor, and in particular to lipid factor.

Results: At baseline 12.5% of the men and of the women presented T2D, while 31.3% of the men and 26.7% of the women were characterized by IFG (p=0.03). For both sexes triglycerides increased in a constant and significant manner going from NFG to the IFG and to T2D subjects, while LDL cholesterol and APO A1 levels decreased in a significant way. Only in the men did total cholesterol and APO B increase significantly going from NFG to IFG to T2D, while HDL cholesterol was characterized by a decreasing trend. The factor analysis showed that there were 4 factors for the men (glucose, obesity, total cholesterol, HDL cholesterol) and 4 for women (glucose, total cholesterol, obesity, HDL cholesterol). For the NFG and IFG men, and the T2D men and women, the HDL cholesterol factor had a significant protective effect on all-cause mortality.

Discussion: the distribution of the lipid profile variables considered in this analysis changes in a significant manner in the NFG, IFG, and T2D group, in different ways in the males and females. For both sexes, however, the factor pertaining to HDL cholesterol appears to have a clearly protective effect on death from all causes.