H85

Summary

Strengths One of the strengths of research based on these data sets is its interdisciplinary character. The EpiLife Center have principal investigators and co-investigators from the following public health-related disciplines: Epidemiology, Psychiatry, Cardiovascular Medicine, Social medicine, Primary health care, Geriatrics & gerontology, Statistics, Nutrition & metabolism, Genetics & molecular epidemiology, Psychology, Education, Sociology, Cancer epidemiology, and Caring sciences. There are also extended links with other research groups throughout Sweden, and through providing a basis to extend our international collaborations. In addition to the EpiLife team, visiting researchers have been collaborating on several of the population studies. ‘The research teams are involved in international research collaborations with studies involving all age groups, from the very young to the very old.’ All samples are systematically obtained, based on birth dates, from the Swedish Population Register, which covers names and addresses of all people living in Sweden. The studies include both persons living in private households as well as in institutions. Weaknesses Response rates 60-85%. Subjective measures become less relevant when the individuals suffer from dementia or other cognitive disorders.

Type of data

Data Source
Registry + Survey

Type of Study
Survey same
Survey different
Crosssection regular
Cohort study

Data gathering method
Telephone
Face-to-face
Registries
Self administered questionnaire
Other: Physical examinations, cognitive testing

Access to data

Conditions of access
Access possible after contacts with principal investigator/responsible research group. Data can be analysed at site and at times as unidentifiable files within the consideration of Swedish rules of data protection and ethical regards.

Type of available data (e.g. anonymised microdata, aggregated tables, etc.)
anonymized microdata and also aggregated tables.

Formats available
Primarily SAS and SPSS, but the dataset is compatible to other formats.

Coverage

Coverage Years of collection, reference years, and sample sizes
Cohort 1901-02: In 1986-87, all 85-year-olds, born July 1, 1901 to June 30, 1902, and living in Gothenburg were included in the study. Half of the sample (n=494, response rate 63%) were examined by psychiatrists. Follow-ups were performed at ages 88, 90, 92, 95, 97, 99, 100, 102, 103, and 104 years. Cohort 1923-24: A representative sample of 85-year-olds born July 1, 1923 to June 30, 1924 were examined (N=571, response rate 61%) in 2008-10. A follow-up at age 88 started late autumn 2011, and continued during 2012. In a longer perspective this cohort will be re-examined at ages 90, 92 and 95 years etc. in the same way as the cohort born 1901-02. Cohort 1930: A representative sample of 85-year-olds born 1930 will be examined in 2015 (N=500-600). We plan follow-ups of this cohort at ages 88, 90, 92 and 95 years etc. in the same way as for previous cohorts of 85-year-olds.

First year of collection
1986

Stratification if applicable
YES – the material can be analysed with respect to age cohorts, gender, medical conditions and socio-economic conditions, education etc.

Base used for sampling

Geographical coverage and breakdowns
Gothenburg

Age range
Individuals aged 70-100 years

Statistical representativeness
Population representative

Coverage of main and cross-cutting topics
See above. H 85 covers several medical, socio-economic and life-course indicators for focus on mental and cognitive capacities. It is connected to the ADL-model as well as social networks and family contexts. All samples are systematically obtained, based on birth dates, from the Swedish Population Register, which covers names and addresses of all people living in Sweden. The studies include both persons living in private households as well as in institutions. Response rates 60-85%. Examinations have been virtually identical at each examination year to enhance possibilities of comparisons, and include psychiatric examinations, key informant interviews, physical examinations, nurse examinations, and examinations by physiotherapists, and psychometric testings. We also examine ADL and IADL, cognitive and emotional function, physical activity, sensory functions, social function (social network) and psychiatric function, as well as chronic diseases. Data on socioeconomic status, marital status, living conditions, housing, social network and other social circumstances, education, religious activity, hobbies and life events are collected. Neurobiological examinations include CT scan of the head, and CSF examinations. Blood sampling is also included, and includes genetic testings of frozen blood samples. This is led by Prof. Kaj Blennow. We process whole frozen blood for DNA using standard procedures. We collaborate with Professor John Hardy, London, in a genome-wide association study (GWAS), which focuses on associations between single-nucleotide polymorphisms (SNPs) and traits like major diseases. http://www.neurophys.gu.se/english/departments/psychiatry_and_neurochemistry/Neuropsychiatric_Epidemiology This work-area studies interactions between psychosocial, biological and genetic risk factors for the development of mental disorders (e.g. depression, anxiety disorders, alcohol and drug abuse, suicidal behavior) and whether the influence of these risk factors and their interactions changes with age and over time. Other objectives are to study whether the rates of mental disorders differ between different birth cohorts and different age groups, whether individuals with these disorders are recognized and properly treated by the health care system, to study preclinical symptoms of depression, to study the influence of genetic factors and biological brain changes on mental disorders in old age, and to study long-term prognosis of mental disorders in relation to recurrence, diagnostic change, chronicity, functional ability, institutionalization, mortality rate, and levels of care. The psychiatric examinations were performed by trained psychiatrists at an outpatient department, in the subject's home or at an institution until 2000. Since then, the examinations are performed by experienced psychiatric research nurses. To minimise the methodological problems with this approach, we perform extensive training programs. The inter-rater reliability tests between nurses and specialists in psychiatry is high, with Kappa values for the presence versus absence of signs and symptoms of depression and dementia between 0.62 and 1.00 indicating “good or excellent” agreement. The psychiatric examinations are semi-structured and include ratings of psychiatric symptoms and signs with the Comprehensive Psychopathological Rating Scale, the Mini-D, and questions about previous mental disorders, sexuality, sleep, and use of psychotropic drugs. Suicidal feelings are rated according to Paykel. The examination also includes tests of mental functioning (e.g. memory, proverbs, language, apraxia, construction, finger agnosia, agraphia, alexia, acalculia, and right-left disorientation), the Mini Mental State Examination, and ratings of other signs common in dementia (e.g. personality changes and motor symptoms). Personality inventories (MNT, CMPS och EPI) are also included. Somatic examinations include history of medical conditions (e.g. hypertension, myocardial infarction, diabetes mellitus, stroke, cardiac failure, atrial fibrillation, pulmonary diseases, fractures, thyroid diseases, head trauma, neurological disorders, cancer), use of health services and questions about urinary function, falls, hearing and vision, dizziness, alcohol and tobacco use. Family history of several psychiatric and somatic disorders is also included. The prescribed and actually taken medication is recorded and classified according to the Anatomical Therapeutic Chemical (ATC) classification system recommended by the World Health Organization. The examinations also include anthropometric measurements, blood pressure, electrocardiogram (ECG), lung function, measures of atherosclerosis, a battery of blood tests, grip strengths and walking capacity. Blood samples are taken after overnight fasting, and include a variety of measurements such as hemoglobin, HbA1c, thyroid function, cholesterol (total, HDL, LDL, triglycerides), homocystein, B12 and folate. Blood, serum and plasma are frozen for future analyses. Psychological examinations regarding memory and intelligence are performed in all examinations. Responsible for these examinations is Professor Boo Johanson, Dept. of Psychology, Göteborg University. Measures include SRB-1, SRB-2, SRB-3, Thurstone Picture Memory, Ten Word Memory List, Clock Test, Prose Recall, Digit Span Forward and Backward. Functional ability: Data is collected on basic abilities in activities of daily living (ADL), instrumental ADL and other abilities, and physical activities, such as walking and exercising. Social factors: Data on socioeconomic status, marital status, living conditions, housing, social network and other social circumstances, education, religious activity, hobbies and life events are collected. Close informant interview. After the examination, the participant is asked for permission to interview a close informant. The interview with a close informant is semi-structured and comprises IQCODE (Jorm), other questions about changes in behavior and intellectual function (e.g. changes in personality, memory, difficulties in finding one’s way in familiar surroundings, intellectual ability, language, psychiatric symptoms, activities of daily living, incontinence, neurological symptoms), family history, medical history (e.g. hypertension, myocardial infaction, diabetes mellitus, stroke, cardiac failure, atrial fibrillation, fractures, thyroid diseases, head trauma, neurological disorders, cancer) and, in case of dementia, questions about age at onset and course. Psychiatric symptoms include e.g. hallucinations, delusions and depression.

Linkage

Standardisation
The Diagnostic and Statistical Manual of Mental Disorders (DSM by American Psychiatric Association and other medical taxonomies. ADL-models also used.

Possibility of linkage among databases
Good technical opportunities to link to other Swedish datasets or registries due to the use of ID – personal identification number, but policies of data protection and ethical considerations have to be regarded.

Data quality

Entry errors if applicable
Selection bias in composing cohorts due to variety in participation from respondents. Response rate vary between 68 – 85%.

Breaks
No particular breaks in research design, but a broad network of interdisciplinary collaboration.

Consistency of terminology or coding used during collection
The core focus is continuing, but the broad national and international contexts contribute to different methodological approaches. This is also a field under development.

Governance

Contact information
Ingmar Skoog
Dept of Neuroscience and Physiology
Wallinsgatan 6
431 41 Mölndal Sweden Phone: 00709-433 681
Email: ingmar.skoog(at)neuro.gu.se
Url: http://snd.gu.se/en/catalogue/study/SND0017; http://www.epilife.sahlgrenska.gu.se/cooperation/International/

Timeliness, transparency
It takes about 3-5 years until the data is released following collection.