Gerontology Research Programme: The Singapore Longitudinal Ageing Studies (SLAS I & II)

The Gerontology Research Programme (GRP) in the National University Singapore's Department of Psychological Medicine, was formed to coordinate and facilitate the conduct of multi-disciplinary research on in a wide range of research on ageing and health. The establishment of the Singapore Longitudinal Aging Cohort will provide a large community-based cohort of elderly subjects for observational studies with useful clinical applications. Research synergy is achieved in terms of pooling multi-disciplinary expertise, and combining genetic, biological, environmental, behavioural, social, clinical, and health services approaches to gerontological research.

The SLAS is the principal longitudinal cohort study in GRP. The SLAS is a community-based longitudinal epidemiologic study that aims to increase the understanding of ageing and health, and the factors that influence the ageing process. SLAS seeks to identify the cognitive, biomedical, lifestyle and behavioral, as well as psychosocial risk and protective factors that affect the transition from healthy ageing to functional impairment, illness and death.

Participants recruited into SLAS are community-dwelling seniors, aged 55 and above, from various areas in Singapore. Participants are approached door-to-door, are provided detailed information regarding their participation, and are required to provide informed consent before enrollment into the study. The study procedure includes a baseline survey upon enrollment, and participants are revisited on a 3-yearly basis thereafter.

Enrolled subjects provide baseline data through structured interviews, physician assessments, laboratory testing, and self-reports of conditions, symptoms, and risk behaviors. Data in the study is collected by trained research staff and nurses. The information to be collected include:

Outcomes:

Primary Outcomes

4 Main Primary Outcomes

1. Mild cognitive impairment and cognitive functioning
2. Frailty
3. Depression, anxiety (Mood disorder I)
4. Successful and healthy ageing

Basic screening followed by diagnostic tests.

Cognitive domain functioning. Particpants are screened fro cogntve impairment using global cognitive tests (MMSE and MOCA). An exhaustive neuropsychological assessment battery is also conducted to assess specific cognitive domain functioning of participants. Selected participants that meet screening criteria, thus indicating the presence of possible cognitive impairment, undergo further testing to determine their cognitive functioning status (cognitively normal, mild cognitive impairment, cognitive decline, or dementia), as diagnosed by a panel of geriatricians, in accordance with the DSM-IV-TR criteria for dementia (1), and the MCI Working Group of the European Consortium on Alzheimer's disease criteria (2).

Frailty assessment. A battery of measures, including self-report, physical assessments and anthropometric measures, is administered to measure the frailty status of the individuals, in accordance with the Fried et al.'s phenotype criteria (3).

Psychiatric assessment. Several self-reported questionnaires are administered to measure the symptomatology of common psychiatric disorders such as depression, among others. Selected participants that meet screening criteria, thus indicating the presence of possible psychiatric disorders, would undergo further testing to determine their mental health state, in accordance with the DSM-IV-TR criteria (1).

Successful and healthy ageing. Successful and healthy ageing is determined by a number of self-reported and objective measurements of health which aim to reflect the overall and physical health, cognitive, emotional and social well-functioning (inclusive of life engagement and life satisfaction) of the individual.

Secondary Outcomes

Physical domain functioning. Self-reported measures as well as physical assessments would be conducted to measure physical functioning, disability and independence in activities of daily living among participants.

Health, health services utilization. Data regarding the history of chronic medical conditions and falls, medication use, use of hospital and primary care services and self-rated health.

Quality of Life. Self-reported measures would be conducted to measure the quality of life amongst the participants.

Mortality. The date of death of participants would be recorded, as well as assessing the Singapore National Registry of Diseases Office (NRDO).

Respiratory functioning. Data regarding respiratory functioning would be collected via a spirometry test.

Risk and protective factors:

Socioeconomic and demographic variables. Information regarding the age, gender, educational status and household income would be collected from the participants via self-report.

Medical history. Information regarding the history of selected medical and mental disorders would be collected from the participants via self-report.

Biological determinants. Biological specimens (blood and urine) will be analyzed for constituents of interest (e.g. micronutrients, lipid and glucose levels, among others).

Pharmacological determinants. The use of pharmacological agents such as anti-inflammatory, cholesterol-lowering and other drugs will be recorded via a self-report measure.

Nutrition. Participants would be assessed on their nutritional status and dietary consumption (NSI screening, MNA screening, food frequency, 2-day food diary). The dietary records are analyzed for nutrients of interest and phytochemicals such as B12, B6, folate, curcumin, and other nutritional supplements.

Lifestyle and health risk behaviors. Lifestyle behaviors measured would include physical, leisure and social activities engagement duration and frequency. Health risk behaviors measured include the body mass index and other anthropometric measures, smoking, customary physical activity, social and productive activities and alcohol use among participants.

Psycho-social data. Self-reported questionnaires are administered to measure life satisfaction, personality, religiosity, social support and asocial network connections for select participants.

Eligibility Criteria:
Inclusion Criteria:

* Ability to self-ambulate
* Adequate cognitive capacity for participation

Exclusion Criteria:

- Individuals with severe physical or mental disabilities were excluded.