The main objectives of Betula study are:
  • To study how memory functions change during adult life and old age;
  • To identify risk factors for dementia;
  • To identify early preclinical signs of dementia.

General Design

Study Design Cohort
General Information on Follow Up (profile, frequency)

The participants were assessed at 6 different time points every 5 years: in 1988-1990, 1993-1995, 1998-2000, 2003-2005, 2008-2010 and 2013-2014.

Recruitment Target
  • Individuals
Number of Participants

4,425

Number of Participants with Biological Samples

4,300

Access

Yes
No
Not Applicable
Don't Know
Possible Access to Data

Possible Access to Biosamples

Other A sub-sample of participants underwent MRI brain scanning at test wave 5 (2009-2010) and 6 (2013-2014).

1. Zimbardo Time Perspective Inventory Based on: (ZTPI) Zimbardo o. Boyds skala (Zimbardo, P., and Boyd, J. N. (1999). Used in Betula: Carelli, M. G., Wiberg, B., & Wiberg, M. (2011). Development and Construct Validation of the Swedish Zimbardo Time Perspective Inventory. European Journal of Psychological Assessment, 27(4), 220–227. https://doi.org/10.1027/1015-5759/a000076<

2. Patient Health Questionnaire-9 Based on: Kroenke, K., Spitzer, RL. & Willimas, JB. (2001). The PHQ-9: validity of a brief depression severity measure. Journal of General Internal Medicine, 16(9), 606-613. https://doi.org/10.1046/j.1525-1497.2001.016009606.x Used in Betula: translated version.

3. Perceived Stress Questionnaire Based on: Levenstein S, Prantera C, Varvo V, Scribano ML, Berto E, Luzi C, Andreoli A. Development of the Perceived Stress Questionnaire: a new tool for psychosomatic research. J Psychosom Res 1993;37:19–32. https://doi.org/10.1016/0022-3999(93)90120-5.

Bergdahl, J., and Bergdahl, M. (2002). Perceived stress in adults: prevalence and association of depression, anxiety and medication in a Swedish population. Stress Health 18, 235–241. doi: 10.1002/smi.946 Used in Betula: translated version.

4. Seasonal Pattern Assessment Questionnaire Based on: Rosenthal, NE., Sack, DA., Gillin, JC., Lewy AJ., Goodwin, FK., Davenport, Y., Mueller, PS., Newsome, DA. & Wehr, TA. (1984). Seasonal affective disorder. A description of the syndrome and preliminary findings with light therapy. Arch Gen Psychiatry, 41(1), 72-80. https://doi.org/10.1001/archpsyc.1984.01790120076010 Used in Betula: translated version

Marker Paper

Nilsson L-G, Adolfsson R, Bäckman L, de Frias C, Molander B, Nyberg L. Betula: A Prospective Cohort Study on Memory, Health and Aging. Aging, Neuropsychology and Cognition,2004; 11 (2-3), 134-148.

Supplementary Information

Nilsson, L.-Gör., Bäckman, L., Erngrund, K., et al. The Betula Prospective Cohort Study: Memory, Health, and Aging. Aging, Neuropsychology, and Cognition,1997; 4(1), 1–32.

Study Timeline

Each colour in the timeline graph below represents a separate Study Population, while each segment in the graph represents a separate Data Collection Event. Clicking on a segment gives more detailed information on a Data Collection Event.

Populations

Betula - Cohort 1

The population consists of randomly selected individuals aged from 35 to 80 years, from the municipality of Umeå, northern Sweden. The gender distribution at inclusion was aimed to reflect the proportion of males and females in each age cohort of the general population.

Sources of Recruitment

General Population
  • Selected sample
Supplementary Information Recruitment of participants was done by randomly obtaining names from the population registry in Umeå, Sweden. The study began with including 1000 randomly selected individuals from the Umeå municipality in the age groups 35, 40, 45, 50, 55, 60, 65, 70, 75 and 80 years. In each age group, 100 participants were selected. The gender distribution at inclusion was aimed to reflect the proportion of males and females in each age cohort of the general population.

Selection Criteria

Age Minimum age 35, Maximum age 80
Country Sweden
Territory Municipality of Umeå, Västerbotten
Other When participants entered the study, they were excluded if they had a severe visual or auditory disability, intellectual disability, dementia or a native language other than Swedish.

Sample Size

Number of Participants

1,000

Supplementary Information about Number of Participants

T1: 1000 participants
T2: 875 participants
T3: 729 participants
T4: 591 participants
T5: 403 participants
T6: 249 participants

Data Collection Events

NameDescriptionStartEnd
Betula - Cohort 1 - T1

At each data collection time point,...

1988 (November)1991 (April)
Betula - Cohort 1 - T2

At Testwave 2 (T2), participants from Sample 1...

1993 (September)1995 (September)
Betula - Cohort 1 - T3

At Testwave 3 (T3) participants from Samples...

1998 (September)2001 (March)
Betula - Cohort 1 - T4

At Testwave 4 (T4) participants from samples...

2003 (September)2005 (November)
Betula - Cohort 1 - T5

At T5 participants from S1 and S3 returned for...

2008 (October)2010 (March)
Betula - Cohort 1 - T6

At Testwave 6 (T6) participants from S1, S3,...

2013 (September)2014 (July)

Betula - Cohort 2

The population consists of randomly selected individuals aged from 35 to 80 years, from the municipality of Umeå, northern Sweden. The gender distribution at inclusion was aimed to reflect the proportion of males and females in each age cohort of the general population.

Sources of Recruitment

General Population
  • Selected sample
Supplementary Information Recruitment of participants was done by randomly obtaining names from the population registry in Umeå, Sweden. At inclusion, close to 1000 randomly selected individuals were recruited from the Umeå municipality in the age groups 35, 40, 45, 50, 55, 60, 65, 70, 75 and 80 years. In each age group, roughly 100 participants were selected. The gender distribution at inclusion was aimed to reflect the proportion of males and females in each age cohort of the general population.

Selection Criteria

Age Minimum age 35, Maximum age 80
Country Sweden
Territory Municipality of Umeå, Västerbotten
Other When participants entered the study, they were excluded if they had a severe visual or auditory disability, intellectual disability, dementia or a native language other than Swedish.

Sample Size

Number of Participants

994

Supplementary Information about Number of Participants

T1: 994 participants
T2: 681 participants

Data Collection Events

NameDescriptionStartEnd
Betula - Cohort 2 - T1

At each data collection time point,...

1993 (September)1995 (September)
Betula - Cohort 2 - T2

At each data collection time point,...

1998 (September)2001 (March)

Betula - Cohort 3

The population consists of randomly selected individuals aged from 40 to 85 years, from the municipality of Umeå, northern Sweden. The gender distribution at inclusion was aimed to reflect the proportion of males and females in each age cohort of the general population.

Sources of Recruitment

General Population
  • Selected sample
Supplementary Information Recruitment of participants was done by randomly obtaining names from the population registry in Umeå, Sweden. At inclusion, close to 1000 randomly selected individuals were recruited from the Umeå municipality in the age groups 40, 45, 50, 55, 60, 65, 70, 75, 80 and 85 years. In each age group, roughly 100 participants were selected. The gender distribution at inclusion was aimed to reflect the proportion of males and females in each age cohort of the general population.

Selection Criteria

Age Minimum age 40, Maximum age 84
Country Sweden
Territory Municipality of Umeå, Västerbotten
Other When participants entered the study, they were excluded if they had a severe visual or auditory disability, intellectual disability, dementia or a native language other than Swedish.

Sample Size

Number of Participants

963

Supplementary Information about Number of Participants

T1: 963 participants
T2: 826 participants
T3: 689 participants
T4: 440 participants
T5: 259 participants

Data Collection Events

NameDescriptionStartEnd
Betula - Cohort 3 - T1

At each data collection time point,...

1993 (September)1995 (September)
Betula - Cohort 3 - T2

At each data collection time point,...

1998 (September)2001 (March)
Betula - Cohort 3 - T3

At each data collection time point,...

2003 (September)2005 (November)
Betula - Cohort 3 - T4

At each data collection time point,...

2008 (October)2010 (March)
Betula - Cohort 3 - T5

At each data collection time point,...

2013 (September)2014 (July)

Betula - Cohort 4

The population consists of randomly selected individuals aged from 35 to 90 years, from the municipality of Umeå, northern Sweden. The gender distribution at inclusion was aimed to reflect the proportion of males and females in each age cohort of the general population.

Sources of Recruitment

General Population
  • Selected sample
Supplementary Information Recruitment of participants was done by randomly obtaining names from the population registry in Umeå, Sweden. At inclusion, close to 600 randomly selected individuals were recruited from the Umeå municipality in the age groups 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85 and 90 years. In each age group, roughly 50 participants were selected. The gender distribution at inclusion was aimed to reflect the proportion of males and females in each age cohort of the general population.

Selection Criteria

Age Minimum age 35, Maximum age 90
Country Sweden
Territory Municipality of Umeå, Västerbotten
Other When participants entered the study, they were excluded if they had a severe visual or auditory disability, intellectual disability, dementia or a native language other than Swedish.

Sample Size

Number of Participants

553

Supplementary Information about Number of Participants

T1: 553 participants

Data Collection Events

NameDescriptionStartEnd
Betula - Cohort 4 - T1

At each data collection time point,...

1998 (September)2001 (March)

Betula - Cohort 5

The population consists of randomly selected individuals aged from 35 to 95 years, from the municipality of Umeå, northern Sweden. The gender distribution at inclusion was aimed to reflect the proportion of males and females in each age cohort of the general population.

Sources of Recruitment

General Population
  • Selected sample
Supplementary Information Recruitment of participants was done by randomly obtaining names from the population registry in Umeå, Sweden. At inclusion, close to 600 randomly selected individuals were recruited from the Umeå municipality in the age groups 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90 and 95 years. In each age group, roughly 45 participants were selected. The gender distribution at inclusion was aimed to reflect the proportion of males and females in each age cohort of the general population

Selection Criteria

Age Minimum age 35, Maximum age 95
Country Sweden
Territory Municipality of Umeå, Västerbotten
Other When participants entered the study, they were excluded if they had a severe visual or auditory disability, intellectual disability, dementia or a native language other than Swedish.

Sample Size

Number of Participants

558

Supplementary Information about Number of Participants

T1: 558 participants

Data Collection Events

NameDescriptionStartEnd
Betula - Cohort 5 - T1

At each data collection time point,...

2003 (September)2005 (November)

Betula - Cohort 6

The population consists of randomly selected individuals aged from 25 to 80 years, from the municipality of Umeå, northern Sweden. The gender distribution at inclusion was aimed to reflect the proportion of males and females in each age cohort of the general population.

Sources of Recruitment

General Population
  • Selected sample
Supplementary Information Recruitment of participants was done by randomly obtaining names from the population registry in Umeå, Sweden. At inclusion, close to 360 randomly selected individuals were recruited from the Umeå municipality in the age groups 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75 and 80 years. In each age group, 30 participants were selected. The gender distribution at inclusion was aimed to reflect the proportion of males and females in each age cohort of the general population.

Selection Criteria

Age Minimum age 25, Maximum age 80
Country Sweden
Territory Municipality of Umeå, Västerbotten
Other When participants entered the study, they were excluded if they had a severe visual or auditory disability, intellectual disability, dementia or a native language other than Swedish.

Sample Size

Number of Participants

357

Supplementary Information about Number of Participants

T1: 357 participants
T2: 66 participants

Data Collection Events

NameDescriptionStartEnd
Betula - Cohort 6 - T1

At each data collection time point,...

2008 (October)2010 (March)
Betula - Cohort 6 - T2

At each data collection time point,...

2013 (September)2014 (July)
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Variables classifications