A Longitudinal Multidimensional Population Study on Brain Aging
Condition: Dementia; Alzheimer Disease; Vascular Dementia
MeSH terms: Alzheimer Disease; Dementia; Dementia, Vascular
Study type: Observational

Summary: 
      Longitudinal observational study of cognitive functions, physical health and biological
      parameters in the whole population living in Abbiategrasso born between 1935 and 1939,1773
      subjects, followed for six years in order to know the prevalence and the incidence of
      dementia and risk and protective factors of normal and pathological mental aging.

      The peculiarities of this study that must assure the outcome efficacy are:

        -  Selected age: since 70-75 years old people represents a transition age from adulthood to
           old age, it is of special interest to study the evolution of psychic and physical
           functions of this population

        -  Whole population not a sample study

        -  Location: the small area involved (Abbiategrasso is a town of 30.000 inhabitants)can
           contribute to guarantee more homogeneity among the subjects and reduce undesired
           variability

        -  multidimensional assessment(biological, clinical, social, psychological data collected)
           After initial screening, the recruited population will be followed up for two more times
           (every two years )
    

Detailed description: 
      Background:

      Dementia is one of the most troubling neurodegenerative syndrome whose prevalence and
      incidence is strongly increasing. The etiology and physiopathology of the process that causes
      dementia are still controversial and largely unknown. So it is of paramount importance to
      isolate risk and protection factors related to dementia syndrome and Alzheimer disease. These
      meager known factors (biological, as well as social and neuropsychological) can be better
      investigated through a multidimensional longitudinal study in a homogeneous population by age
      and place.

      Method:

      People belonging to the selected population (1773 subjects living in Abbiategrasso and born
      between 1935 - 1939) were invited to participate at a comprehensive assessment which was
      divided in two appointments:

        -  a first appointment (about 1 hour and half) for blood sample, social questionnaire,
           anthropometric and walking speed evaluation ;

        -  a second one (2 hours)for clinical examination and neuropsychological assessment of mood
           and cognitive function.

      Recruitment. People were recruited through several steps:

        -  involvement of the family doctor;

        -  a general call, based on age group(1935,1936, 1937, 1938, 1939), since to be born in the
           same year is an identity mark for these generations;

        -  kick-off meetings for each age class explaining aims and methods of the research,
           followed by a party with music, plays and some lotteries

        -  a letter with the date of the appointment followed by the phone call whenever the phone
           number is available

        -  further letters and call until either a rejection or an appointment was taken.

      Assessment. Professionals and instruments:

        -  Trained interviewers, one social worker and two nurses, administer the social
           questionnaire that is partly derived from the CERAD and from other longitudinal studies.

        -  Trained psychologists administer a neuropsychological battery exploring mood (GDS 15
           items), verbal and visual memory (Rey 15-item Memory Test, and the Rey-Osterrieth
           Complex Figure Test (ROCF) recall; Babcock Story Recall Test ), executive function (
           TMTA and TMTB; copy of ROCF), attention (Numerical Attention), abstract reasoning
           (Raven's Coloured Progressive Matrices), screening cognitive test (Clock test and MMSE).

        -  Clinical interview and visit are executed by expert geriatricians, members of the same
           geriatric staff who apply diagnostic criteria for dementia (DSM IV), Alzheimer disease
           (NINCDS ADRDA diagnostic criteria); Vascular dementia (NINDS -AIREN criteria); Lewy Body
           dementia (third report, DLB consortium); frontotemporal dementia ( 2002 modified
           Consensus conference criteria). Other cognitive problems were classified as Mild
           Cognitive Impairment (MCI) following Petersen's criteria or Cognitive Impairment No
           Dementia (CIND) when cognitive impairments are in areas other than memory and they do
           not meet whole criteria for dementia. Every diagnostic conclusion is revised by another
           doctor; in case of discrepancies a third geriatrician, chief of the study, intervenes to
           arbitrate.

      All the instruments were pre tested for inter rater reliability in a similar population
      attending a geriatric day hospital, and some general agreement sessions were performed before
      and during the screening.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        All the 1773 residents of Abbiategrasso, a town of 30.000 inhabitants near Milan, Lombardy,
        Italy, born from 1935 to 1939 : 1724 subjects meets the inclusion criteria
      
Biospecimen description: 
      whole blood and serum
    
Keywords: dementia; mild cognitive impairment; prevalence; incidence; elderly; longitudinal study; population study