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.

LifeGene is a national collaborative project designed to build up a resource for research in all medical disciplines, enabling new and groundbreaking research on the relationships among heredity, environment and lifestyle. The study includes studying several hundred thousand Swedes with the aim of creating new tools to prevent, diagnose and treat our most common diseases. LifeGene constitutes a platform for a myriad of biomedical research projects. Researchers not only in biomedicine and biotechnology but also behavioral and social sciences may benefit from access to LifeGene. By combining a biological perspective with e-epidemiology, LifeGene opens up new possibilities for a greater understanding of the interplay between heredity, lifestyle and the environment as regards to our most common diseases.

The National Child Development Study (NCDS) is a longitudinal study which follows the lives of 17,000 people born in England, Scotland and Wales in a single week of 1958. Also known as the 1958 Birth Cohort Study, it collects information on physical and educational development, economic circumstances, employment, family life, health behaviour, wellbeing, social participation and attitudes.

Since the birth survey in 1958, there have been nine further ‘sweeps’ of all cohort members at ages 7, 11, 16, 23, 33, 42, 46, 50 and 55. In 2003 (at age 45), 9,000 cohort members also participated in a special bio-medical survey to learn more about how development, environments and lifestyles affect people’s health. CLS will carry out a new survey of the NCDS cohort at age 60 in 2018.

NCDS is part of CLOSER (Cohort & Longitudinal Studies Enhancement Resources) which aims to maximise the use, value and impact of the UK’s longitudinal studies.

Recruitment Period: 2004
Sample size at start or planned sample size if still recruiting: 16,122 (15,770 households included at Sweep 1; 352 ethnic boost interviews added at Sweep 4)
Estimated current sample size: 15,629
Age at recruitment: 13-14

Next Steps (previously known as the Longitudinal Study of Young People in England – LSYPE) is a major innovative cohort study of young people. The study began in 2004 and included all young people in Year 9, aged between 13 and 14, who attended state and independent schools in England.

Next Steps is one of the main information sources for the formation and appraisal of policies relating to young people and will continue to be so for at least the next 10 years. The baseline data will be used to monitor the progress of the cohort group, evaluate the success of policies aimed at this group and provide an evidence base for further policy development. The study brings together data from a wide range of sources and reflects the variety of influences on learning and progression.

Following the initial survey at age 13-14, the cohort members were visited every year until 2010, when they were age 19-20. Young people were interviewed along with their parents up to sweep 4 (age 17).

The most recent survey took place in 2015/16, when the cohort members were 25 years old. It maintained the strong focus on education, but the content was broadened to become a more multi-disciplinary research resource. Data was collected about cohort members’ housing and family life, employment and economic circumstances, education and job training, physical and emotional health, and identity and participation. A wide range of administrative data linkage consents were collected in the domains of health, education, economics and criminal behaviour.

The Nurses’ Health Study II (NHS II) was established by Dr. Walter Willett and colleagues in 1989 with funding from the National Institutes of Health to study oral contraceptives, diet, and lifestyle risk factors in a population younger than the original NHS cohort.

Why a new cohort of nurses?
This younger generation of nurses included women who started using oral contraceptives during adolescence and were thus maximally exposed during their early reproductive life. Several case-control studies suggesting such exposures might be associated with substantial increases in breast cancer risk provided a particularly strong justification for investment in this large cohort. Researchers also planned to collect detailed information on the types of oral contraceptives used, which was not obtained in the Nurses’ Health Study.

In addition, NHS II obtained information on physical activity and diet in adolescence and early adult life.

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 Malaysian Cohort study was initiated in 2005 by the Malaysian government. The top-down approach to this population-based cohort study ensured the allocation of sufficient funding for the project which aimed to recruit 100 000 individuals aged 35–70 years. Participants were recruited from rural and urban areas as well as from various socioeconomic groups. The main objectives of the study were to identify risk factors, to study gene-environment interaction and to discover biomarkers for the early detection of cancers and other diseases. At recruitment, a questionnaire-based interview was conducted, biophysical measurements were performed and biospecimens were collected, processed and stored. Baseline investigations included fasting blood sugar, fasting lipid profile, renal profile and full blood count. Active follow-up and reassessment started in 2013 and to date 35,000 participants have been reassessed including biospecimens.

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.

ULSAM is a unique, ongoing, longitudinal, epidemiologic study based on all available men, born between 1920 and 1924, in Uppsala County, Sweden. The men were investigated at the ages of 50, 60, 70, 77, 82 88 and 93 years. The reinvestigations in ULSAM were based on the previous investigations. Full screening and official registry data is available in our databases and more data is continuously added.

Health examination at 93 years of age was carried out between December 2013 and March 2015. To this examination 245 men have been invited. Totally 147 men (60%) participated in the investigation. Of these, 23 men were examined at the hospital and 102 were visited at home by a nurse. In addition, 22 men completed only a questionnaire. To this examination even spouses were invited. In the complete examination 43 spouses have participated and 11 completed only a questionnaire.