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Survival advantage of cohort participation attenuates over time: results from three long-standing community-based studies.

TitleSurvival advantage of cohort participation attenuates over time: results from three long-standing community-based studies.
Publication TypeJournal Article
Year of Publication2020
AuthorsZheng Z, Rebholz CM, Matsushita K, Hoffman-Bolton J, Blaha MJ, Selvin E, Wruck L, Sharrett ARichey
Secondary AuthorsCoresh JJ
JournalAnn Epidemiol
Volume45
Pagination40-46.e4
Date Published2020 05
ISSN1873-2585
KeywordsAged, Atherosclerosis, Cohort Studies, Community-Based Participatory Research, Epidemiologic Studies, Female, Heart Diseases, Humans, Male, Maryland, Middle Aged, Mortality, Neoplasms, Risk Factors, Selection Bias, Stroke, United States
Abstract

PURPOSE: Cohort participants usually have lower mortality rates than nonparticipants, but it is unclear if this survival advantage decreases or increases as cohort studies age.

METHODS: We used a 1975 private census of Washington County, Maryland, to compare mortality among cohort participants to nonparticipants for three cohorts, Campaign Against Cancer and Stroke (CLUE I), Campaign Against Cancer and Heart Disease (CLUE II), and Atherosclerosis Risk In Communities (ARIC) initiated in 1974, 1989, and 1986, respectively. We analyzed mortality risk using time-truncated Cox regression models.

RESULTS: Participants had lower mortality risk in the first 10 years of follow-up compared with nonparticipants (fully adjusted average hazard ratio [95% confidence intervals] were 0.72 [0.68, 0.77] in CLUE I, 0.69 [0.65, 0.73] in CLUE II, and 0.74 [0.63, 0.86] in ARIC), which persisted over 20 years of follow-up (0.81 [0.78, 0.84] in CLUE I, 0.87 [0.84, 0.91] in CLUE II, and 0.90 [0.83, 0.97] in ARIC). This lower average hazard for mortality among participants compared with nonparticipants attenuated with longer follow-up (0.99 [0.96, 1.01] after 30+ years in CLUE I, 1.02 [0.99, 1.05] after 30 years in CLUE II, and 0.95 [0.89, 1.00] after 30+ years in ARIC). In ARIC, participants who did not attend visits had higher mortality, but those who did attend visits had similar mortality to the community.

CONCLUSIONS: Our results suggest the volunteer selection for mortality in long-standing epidemiologic cohort studies often diminishes as the cohort ages.

DOI10.1016/j.annepidem.2020.03.010
Alternate JournalAnn Epidemiol
PubMed ID32371044
PubMed Central IDPMC7294871
Grant ListR01 DK089174 / DK / NIDDK NIH HHS / United States
K01 DK107782 / DK / NIDDK NIH HHS / United States
R21 HL143089 / HL / NHLBI NIH HHS / United States
HHSN268201700002C / HL / NHLBI NIH HHS / United States
HHSN268201700001I / HL / NHLBI NIH HHS / United States
HHSN268201700004C / HL / NHLBI NIH HHS / United States
HHSN268201700003I / HL / NHLBI NIH HHS / United States
K24 DK106414 / DK / NIDDK NIH HHS / United States
HHSN268201700004I / HL / NHLBI NIH HHS / United States
HHSN268201700005C / HL / NHLBI NIH HHS / United States
HHSN268201700001C / HL / NHLBI NIH HHS / United States
HHSN268201700003C / HL / NHLBI NIH HHS / United States
HHSN268201700002I / HL / NHLBI NIH HHS / United States
HHSN268201700005I / HL / NHLBI NIH HHS / United States