The Ohsaki Cohort 2006 Study: design of study and profile of participants at baseline.
BACKGROUND
Large-scale cohort studies conducted in Japan do not always include psychosocial factors as exposures. In addition, such studies sometimes fail to satisfactorily evaluate disability status as an outcome.


METHODS
This prospective cohort study comprised 49 603 (22 438 men and 27 165 women) community-dwelling adults aged 40 years or older who were included in the Residential Registry for Ohsaki City, Miyagi Prefecture, in northeastern Japan. The baseline survey, which included psychosocial factors, was conducted in December 2006. Follow-up of death, immigration, cause of death, cancer incidence, and long-term care insurance certification was started on 1 January 2007.


RESULTS
The response rate was 64.2%. In general, lifestyle-related conditions in the study population were similar to those of the general Japanese population; however, the proportion of male current smokers was higher in the cohort. The association between age and the proportion of those reporting psychological distress showed a clear U-shaped curve, with a nadir at age 60 to 69 years in both men and women, although more women were affected by such distress than men. The proportion of those who reported a lack of social support was highest among those aged 40 to 49 years. Most men and women surveyed did not participate in community activities. Among participants aged 65 years or older, 10.9% of participants were certified beneficiaries of the long-term care insurance system at baseline.


CONCLUSIONS
The Ohsaki Cohort 2006 Study is a novel population-based prospective cohort study that focuses on psychosocial factors and long-term care insurance certification.
Kuriyama
Shinichi
S
Division of Epidemiology, Department of Public Health and Forensic Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan. s-kuri@mail.tains.tohoku.ac.jp
Nakaya
Naoki
N
Ohmori-Matsuda
Kaori
K
Shimazu
Taichi
T
Kikuchi
Nobutaka
N
Kakizaki
Masako
M
Sone
Toshimasa
T
Sato
Fumi
F
Nagai
Masato
M
Sugawara
Yumi
Y
Tomata
Yasutake
Y
Akhter
Munira
M
Higashiguchi
Mizuka
M
Fukuchi
Naru
N
Takahashi
Hideko
H
Hozawa
Atsushi
A
Tsuji
Ichiro
I
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015340:Epidemiologic Research Design; D005260:Female; D006801:Humans; D007353:Insurance, Long-Term Care / Q000706:statistics & numerical data*; D007564:Japan / Q000453:epidemiology; D008019:Life Style; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012042:Registries; D012111:Residence Characteristics; D012737:Sex Factors; D012907:Smoking / Q000453:epidemiology; D012944:Social Support; D013315:Stress, Psychological / Q000453:epidemiology*
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