Self-reported sleep duration and prediction of proteinuria: a retrospective cohort study.
BACKGROUND
Although multiple studies have shown that sleep duration is a predictor of cardiovascular diseases and mortality, few studies have reported an association between sleep duration and chronic kidney disease.


METHODS
Retrospective cohort study.


METHODS
6,834 employees of Osaka University aged 20-65 years who visited Osaka University Healthcare Center for their mandatory annual health examinations between April 2006 and March 2010 and did not have estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m(2), proteinuria, or treatment for self-reported kidney disease.


METHODS
Self-reported questionnaires about life style, including sleep duration, and blood and urine testing at the first examinations during the study period. An association between sleep duration and outcome was assessed using multivariate Poisson regression models adjusting for clinically relevant factors.


RESULTS
Time to the development of proteinuria defined as 1+ or higher by dipstick test.


RESULTS
Self-reported baseline sleep duration was 6.0 ± 0.9 hours, which reflected the mean sleep duration during a median of 2.5 (25th-75th percentile, 1.4-3.9) years of the observational period. Development of proteinuria was observed in 550 employees (8.0%). A multivariate Poisson regression model clarified that shorter sleep duration, especially 5 or fewer hours, was associated with the development of proteinuria in a stepwise fashion (vs 7 hours; incidence rate ratios of 1.07 [95% CI, 0.87-1.33; P = 0.5], 1.28 [95% CI, 1.00-1.62; P = 0.05], and 1.72 [95% CI, 1.16-2.53; P = 0.007] for 6, 5, and ≤4 hours, respectively), along with younger age, heavier current smoking, trace urinary protein by dipstick test, higher eGFR, higher serum hemoglobin A(1c) level, and current treatment for heart disease. A stepwise association between shorter sleep duration and the development of proteinuria also was verified in 4,061 employees who did not work the night shift.


CONCLUSIONS
Self-reported sleep duration might be biased. Results in a single center should be confirmed in the larger cohort including different occupations.


CONCLUSIONS
Short sleep duration, especially 5 or fewer hours, was a predictor of proteinuria.
Department of Geriatric Medicine and Nephrology, Osaka University Graduate School of Medicine, Suita, Japan. yamamoto@kid.med.osaka-u.ac.jp
Ryohei
R
Yamamoto
Yasuyuki
Y
Nagasawa
Hirotsugu
H
Iwatani
Maki
M
Shinzawa
Yoshitsugu
Y
Obi
Junya
J
Teranishi
Toshihiro
T
Ishigami
Keiko
K
Yamauchi-Takihara
Makoto
M
Nishida
Hiromi
H
Rakugi
Yoshitaka
Y
Isaka
Toshiki
T
Moriyama
D000328:Adult; D000368:Aged; D015331:Cohort Studies; D005260:Female; D005544:Forecasting; D006801:Humans; D008297:Male; D008875:Middle Aged; D011507:Proteinuria / Q000209:etiology* / Q000517:prevention & control; D012189:Retrospective Studies; D057566:Self Report; D012890:Sleep; D013997:Time Factors; D055815:Young Adult