Leiden 85-plus Study


Baseline: 1997 – 1999
Follow-up1: 1998 – 2000
Follow-up2: 1999 – 2001
Follow-up3: 2000 – 2002
Follow-up4: 2001 – 2003
Follow-up5: 2002 – 2004
Follow-up6: 2002 – 2015

Sample size

Baseline: 599 participants
Follow-up Age 86: 510 participants
Follow-up Age 87: 445 participants
Follow-up Age 88: 391 participants
Follow-up Age 89: 330 participants
Follow-up Age 90: 277 participants

Sample population


Sample residence


Survey mode

Competence in activities of daily living (ADL) was measured with the Groningen Activity Restriction Scale (GARS). Impression of the subject’s daily functioning, cognition, and mood was recorded in a standardized questionnaire, using a four-point scale (very good, good, poor, very poor). All subjects’ general practitioners or subject’s nursing home physicians were interviewed to assess the medical history for number of cardiovascular pathologies and chronic diseases, including diabetes mellitus, chronic obstructive pulmonary disease (COPD), arthritis, malignancy, and Parkinson disease (PD), for each subject.

For participants with severe cognitive impairment, information was obtained from a responsible person. Cognitive function was assessed with the Mini-Mental State Examination (MMSE). Severe cognitive impairment was defined as an MMSE score of 18 points or lower. In participants without severe cognitive impairment, depressive symptoms were measured with the 15-item Geriatric Depression Scale (GDS-15). Cognitive speed was measured with two neuro-psychological tests, the Letter Digit Coding test (processing speed) and an abbreviated 40-item version of the Stroop test (attention). Memory was measured with the 12-Word Learning test, assessing immediate and delayed recall.

Electrocardiograms were recorded and each year up to age 90 years blood pressure was measured twice a month with an interval of 2 weeks.

A blood sample was taken.

For all subjects socio-demographic characteristics such as gender, marital state, and type of housing were available from the municipal registry. Mean income of neighbourhood of residence was used as indication of socio-economic status. Mean income after taxes in the neighbourhood of residence was obtained by postal codes.

Pharmacists provided detailed information on all medication used by participants

Longitudinal or cross-section study


Data sources

Cognitive measures
Physical measures
Administrative databases: Health databases, vital statistics databases, Socioeconomic databases
Others: Information from pharmacist

Main topics

Effect of gender on cognitive function, role of formal education


The objective of this study was to explore whether there is an effect of gender on cognitive function and whether differences in limited formal education explain differences on cognitive function between elderly women and men.

Scientific domain

Social Science, Medicine

Age studies subcategories
Age Study (85+)

Universiteit Leiden
Faculteit Geneeskunde, Divisie 3, Public Health en Eerstelijnsgeneeskunde


Dr. Jacobijn Gussekloo


A. Bootsma-van der Wiel, E., van Exel, E., de Craen, A.J.M., Gussekloo, J., Lagaay, A.M., Knook, D.L., Westendorp, R.G.J. A high response is not essential to prevent selection bias: Results from the Leiden 85-plus study. Journal of Clinical Epidemiology 2002;55:1119-1125