The Atherosclerosis Risk in Communities Study (ARIC) is a prospective epidemiologic study conducted in four U.S. communities. ARIC is designed to investigate the etiology and natural history of atherosclerosis, the etiology of clinical atherosclerotic diseases, and variation in cardiovascular risk factors, medical care and disease by race, gender, location, and date. Since 2011 a large ancillary study, the ARIC Neurocognitive Study (ARIC-NCS) has been assessing neurocognitive status and adjudicating possible cases of dementia.

Four ARIC field centers each randomly selected and recruited a cohort sample of approximately 4,000 individuals aged 45-64 from a defined population in their community. A total of 15,792 participants received an extensive baseline examination (visit 1, 1987-1989), including medical, social, and demographic data collection. Subsequent examinations occurred in 1990-92 (visit 2), 1993-95 (visit 3), 1996-98 (visit 4), 2011-2013 (visit 5) and 2016-2017 (visit 6). Visit 7 (2018-2019) is currently in progress. Follow-up occurs annually (semi-annually since 2012) by telephone to maintain contact with participants and to assess health status of the cohort.

The ZARADEMP project (ZARAgoza DEMentia
DEPression project) was designed as a longitudinal,
community-based study to examine the incidence
of dementia and the risk factors in incident cases of
dementia. It was carried out in Zaragoza, a typical,
large city in Spain, with an important proportion
of inhabitants coming from surrounding rural
areas (12). A stratified random sample of individuals
55 years of age and older, with proportional
allocation by age and sex, drawn from the eligible
individuals (n = 157 787) in the Spanish official
census lists of 1991, was invited to participate in
the baseline examination.

The Cardiovascular Health Study (CHS) is an NHLBI-funded observational study of risk factors for cardiovascular disease in adults 65 years or older. Starting in 1989, and continuing through 1999, participants underwent annual extensive clinical examinations. Measurements included traditional risk factors such as blood pressure and lipids as well as measures of subclinical disease, including echocardiography of the heart, carotid ultrasound, and cranial magnetic-resonance imaging (MRI). At six month intervals between clinic visits, and once clinic visits ended, participants were contacted by phone to ascertain hospitalizations and health status.

Information on dementia comes from two Ancillary Studies. The CHS Cognition Study (Dr. Lewis Kuller, PI) included 3608 participants who had an MRI in 1992-94 and who were followed for dementia through 1999. A follow-up study was done at the Pittsburgh field center that included 532 participants followed through 2013 (Dr. Oscar Lopez,PI).

The study is a prospective cohort study that included 400 subjects with MCI enrolled in at Huashan Hospital in Shanghai, China and a followed-up once annually for three years. The objectives are to identify individuals with MCI who convert to AD and to explore factors associated with the conversion. The observation time point is every 12 months and phone interview on 6th, 18th month. The primary endpoint was the time from diagnosis to the conversion from MCI to Probable AD Dementia. The secondary endpoints are the time to conversion from MCI to “Possible AD Dementia” or “Probable AD Dementia”, time to Conversion from MCI to “All-cause Dementia”, Overall survival, Changes in Neuropsychological examinations and Changes in MRI from baseline to the end of follow-up. The planned research duration was from Jan 2012 to Dec 2016.

ASPREE is a double-blind, randomized, placebo-controlled primary prevention trial designed to assess whether daily active treatment of 100 mg enteric-coated aspirin will extend the duration of disability-free life in healthy participants aged 70 years and above except for Hispanic and African American minority groups in the U.S. where the minimum age of entry is 65 years.

The primary objective is to determine whether low-dose aspirin prolongs life, or life free of dementia, or life free of significant, persistent physical disability in the healthy elderly. Secondary objectives relate to the effects of low-dose aspirin on the key outcome areas of death, cardiovascular disease, dementia and cognitive decline, cancer, physical disability, depression and major bleeding episodes. Variables were collected annually through visits and for the purposes of retention telephone calls were scheduled at set points through the 7 years.

Since 1993 the EAS has used systematic recruiting methods to assemble a cohort of over 2,200 elderly individuals from the Bronx, 26% of whom are African American. The EAS sample is broadly representative of the elderly population in one of the poorest and most racially and ethnically diverse urban counties in the United States.

The EAS has developed, tested, and applied strategies designed to meet the recruitment and retention challenges that may arise when conducting research studies with older adults. In 2004, the EAS began using the Registered Voter Lists (RVL) for Bronx County for continuous recruitment efforts. Individuals of at least 70 years of age, Bronx residents, non-institutionalized and English speaking are randomly selected from updated RVL and sent a letter followed by a screening telephone call. Persons who complete the telephone screening battery and agree to participate in clinical follow-up are invited to enroll. Continuing enrollment has resulted in over 2200 participants by 2017.

A family-based cohort study that is embedded in the Genetic Research in Isolated Populations (GRIP) program in the South West of the Netherlands. The aim of this program was to identify genetic risk factors in the development of complex disorders. For the ERF study, 22 families that had at least five children baptized in the community church between 1850-1900 were identified with the help of genealogical records. All living descendants of these couples and their spouses were invited to take part in the study. Data collection started in June 2002 and was finished in February 2005 (n=2065).

A population-based prospective study of cerebro-cardiovascular diseases was begun in 1961 in the town of Hisayama, a suburb of the Fukuoka metropolitan area of Kyushu Island in Japan. In addition, comprehensive surveys of cognitive impairment in the elderly of this town have been conducted since 1985. In 1988, a total of 1,228 residents aged ?60 years (91.1% of the total population in this age group) participated in a screening examination for the present study. After exclusion of 33 subjects who had dementia, 90 who had already had breakfast, 5 who were on insulin therapy, and 81 who could not complete the OGTT, a total of 1,019 subjects without dementia underwent the OGTT. From a total of 1,019 subjects, 2 who died before starting follow-up were excluded, and the remaining 1,017 subjects (437 men and 580 women) were enrolled in this study.

The subjects were followed up prospectively for 15 years, from December 1988 to November 2003 (mean 10.9 years; SD 4.1 years).

In 1999 the Swedish Ministry for Social Affairs promoted and supported a national project aimed at monitoring and evaluating the care-of-the-elderly system in Sweden. To achieve these aims, four longitudinal individual-based data collection describing the aging process and encompassing the care system as whole, has been initiated. This project was named The Swedish National study on Aging and Care (SNAC).

SNAC-K is conducted by the Stockholm Gerontology Research Center in collaboration with Aging Research Center (ARC), Karolinska Institutet.

SNAC-K includes two studies: SNAC-K population study and SNAC-K care system study.

The Maastricht Study is an extensive phenotyping study that focuses on the etiology of type 2 diabetes, its classic complications (cardiovascular disease, nephropathy, neuropathy and retinopathy), and its emerging comorbidities, including cognitive decline, depression, and gastrointestinal, respiratory and musculoskeletal diseases. The study uses advanced state-of-the-art imaging techniques and extensive biobanking to determine health status in a population-based cohort of 10,000 individuals that is enriched with type 2 diabetes participants. The Maastricht Study is expected to become one of the most extensive phenotyping studies in both the general population and type 2 diabetes participants worldwide.

The Maastricht Study allows researchers access to data to encourage publications of high quality papers and presentations. External researchers (those without an MUMC or UM affiliation) can only submit a research proposal in cooperation with a member of the Maastricht Study Management Team and/or Maastricht Study Participating researchers.