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.

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.

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.

The primary objective of the Jackson Heart Study is to investigate the causes of cardiovascular disease (CVD) in African Americans to learn how to best prevent this group of diseases in the future.

Specific objectives include:
• Identification of factors, which influence the development, and worsening of CVD in African Americans, with an emphasis on manifestations related to high blood pressure (such as remodeling of the left ventricle of the heart, coronary artery disease, heart failure, stroke, and disorders affecting the blood vessels of the kidney).
• Building research capabilities in minority institutions at the undergraduate and graduate level by developing partnerships between minority and majority institutions and enhancing participation of minority investigators in large-scale epidemiologic studies.
• Attracting minority students to and preparing them for careers in health sciences.

The Jackson Heart Study conducted three cohort examinations, an initial clinic examination from 2000 to 2004 (Exam1), followed by a second exam from 2005 to 2008 (Exam 2) and a final exam in 2009 to 2013 (Exam 3). Starting in 2001, participants have been contacted annually, and ascertainment of hospitalizations for cardiovascular events and deaths is ongoing.

The Nurses’ Health Study is a longitudinal population study aimed initially to examine the relation between the use of oral contraceptives, cigarette smoking, and risk of major illnesses in women, mainly cancer and cardiovascular diseases. Since then, the study broadened to include the evaluation of health consequences of many lifestyle practices, including diet, physical activity, and specific forms of hormone therapy.

The participants are registered nurses, aged 30 to 55 years and married at the time of recruitment in 1976, and who lived in the 11 most populous states (California, Connecticut, Florida, Maryland, Massachusetts, Michigan, New Jersey, New York, Ohio, Pennsylvania and Texas).

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.

The Chinese Longitudinal Healthy Longevity Study (CLHLS) is a large-scale population-based study on health status and quality of life of the elderly in 23 provinces (out of 31 provinces) of China since 1998 with 8 waves so far. The study covers approximately 85% of the total population of China and was conducted to shed light on the determinants of human healthy longevity. The CLHLS tried to interview all consenting centenarians in the sampled counties and cities. For each centenarian interviewee, compatible nearby un-related elderly and younger participants were interviewed, including about one nonagenarian aged 90-99, one octogenarian aged 80-89, 1.5 young-old adult aged 65-79 and 0.7 middle-aged adult aged 40-64. Detailed longitudinal data on physical and mental health, cognitive function, social participation, etc. at old ages were collected from a total of 96,805 face-to-face interviews with 16,557 centenarians, 23,081 nonagenarians, 25,842 octogenarians, 19,650 younger elders aged 65-79, and 11,675 aged 35-64 in the completed 7 waves from 1998 to 2014. For the 26,701 participants who died between these seven waves, data on mortality and quality of life before death (i.e., degree/length of disability and suffering before death) were collected in interviews with a close family member of the deceased. The completed seven waves of CLHLS had collected DNA samples from 24,693 participants, including 4,849 centenarians, 5,190 nonagenarians, 5,274 octogenarians, 4,770 aged 65-79, and 4,609 aged 40-64. The 8th wave of CLHLS is ongoing and expected to be completed by the end of July 2018.

The Prospective Epidemiological Risk Factor (PERF) Study is an ambidirectional population-based study of postmenopausal women set up with the purpose of obtaining a better understanding of the aetiology and pathogenesis of age-related diseases. Participants were recruited from a source population of 8875 women residing in Denmark. The baseline examination (PERF I) comprised 5855 women with mean age of 70.8 years (49.7-88.8) and took place between 1999 and 2001. All subjects have been followed up with registry linkage using population-based national registries. Further, a subcohort was re-invited to attend a follow-up visit between 2013 and 2014 (PERF II). Registry data are available for all baseline participants. From the baseline population, 2103 were enrolled in PERF II.