Remodelling of biological parameters during human ageing: evidence for complexregulation in longevity and in type 2 diabetes.

Factor structure analyses have revealed the presence of specific biologicalsystem markers in healthy humans and diseases. However, this type of approach in very old persons and in type 2 diabetes (T2DM) is lacking. A total sample of2,137 Italians consisted of two groups: 1,604 healthy and 533 with T2DM. Age(years) was categorized as adults (≤65), old (66-85), oldest old (>85-98) andcentenarians (≥99). Specific biomarkers of routine haematological and biochemicaltesting were tested across each age group. Exploratory factorial analysis (EFA)by principal component method with Varimax rotation was used to identify factors including related variables. Structural equation modelling (SEM) was applied toconfirm factor solutions for each age group. EFA and SEM identified specificfactor structures according to age in both groups. An age-associated reduction offactor structure was observed from adults to oldest old in the healthy group(explained variance 60.4% vs 50.3%) and from adults to old in the T2DM group(explained variance 57.4% vs 44.2%). Centenarians showed three-factor structuresimilar to those of adults (explained variance 58.4%). The inflammatory componentbecame the major factor in old group and was the first one in T2DM. SEM analysis in healthy subjects suggested that the glucose levels had an important role inthe oldest old. Factorial structure change during healthy ageing was associatedwith a decrease in complexity but showed an increase in variability andinflammation. Structural relationship changes observed in healthy subjectsappeared earlier in diabetic patients and later in centenarians.