Jinhong Cao1, Ehab S Eshak1,2, Keyang Liu1, Isao Muraki1, Renzhe Cui1, Hiroyasu Iso3, Akiko Tamakoshi4. 1. Public Health, Department of Social Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita-shi, 565-0871, Osaka, Japan. 2. Department of Public Health, Community and Preventive Medicine, Faculty of Medicine, Minia University, Minia, Egypt. 3. Public Health, Department of Social Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita-shi, 565-0871, Osaka, Japan. iso@pbhel.med.osaka-u.ac.jp. 4. Department of Public Health, Faculty of Medicine, Hokkaido University, Sapporo, Japan.
Abstract
PURPOSE: The evidence on beneficial or adverse effects of sleep duration on risk of breast cancer remains controversial and limited, especially in Asia. METHODS: A prospective study of 34,350 women aged 40-79 years in whom sleep duration, and menstrual and reproductive histories were determined by a self-administered questionnaire. The follow-up period was from 1988 to 2009, and hazard ratios (HRs) with 95% confidence intervals (CIs) of breast cancer incidence were calculated for shorter sleep duration in reference to sleep duration of ≥ 8 h/day by Cox proportional hazard models. RESULTS: During 19.2-year median follow-up (236 cases), we found a significant inverse association between sleep duration and risk of breast cancer, especially among postmenopausal women and women with low parity (nulliparous and women with < 3 children); the multivariable HRs (95% CIs) among postmenopausal women who reported 7 h/day and ≤ 6 h/day of sleep in reference to ≥ 8 h/day were 1.49 (0.81-2.76) and 1.98 (1.08-3.70) (P for trend = 0.028), respectively, and the corresponding values among women with low parity were 1.50 (0.96-2.35) and 1.76 (1.01-2.79) (P for trend = 0.018). CONCLUSIONS: Short sleep duration was associated with increased risk of incident breast cancer, especially among postmenopausal women and women with low parity.
PURPOSE: The evidence on beneficial or adverse effects of sleep duration on risk of breast cancer remains controversial and limited, especially in Asia. METHODS: A prospective study of 34,350 women aged 40-79 years in whom sleep duration, and menstrual and reproductive histories were determined by a self-administered questionnaire. The follow-up period was from 1988 to 2009, and hazard ratios (HRs) with 95% confidence intervals (CIs) of breast cancer incidence were calculated for shorter sleep duration in reference to sleep duration of ≥ 8 h/day by Cox proportional hazard models. RESULTS: During 19.2-year median follow-up (236 cases), we found a significant inverse association between sleep duration and risk of breast cancer, especially among postmenopausal women and women with low parity (nulliparous and women with < 3 children); the multivariable HRs (95% CIs) among postmenopausal women who reported 7 h/day and ≤ 6 h/day of sleep in reference to ≥ 8 h/day were 1.49 (0.81-2.76) and 1.98 (1.08-3.70) (P for trend = 0.028), respectively, and the corresponding values among women with low parity were 1.50 (0.96-2.35) and 1.76 (1.01-2.79) (P for trend = 0.018). CONCLUSIONS: Short sleep duration was associated with increased risk of incident breast cancer, especially among postmenopausal women and women with low parity.
Authors: Anna Brzecka; Karolina Sarul; Tomasz Dyła; Marco Avila-Rodriguez; Ricardo Cabezas-Perez; Vladimir N Chubarev; Nina N Minyaeva; Sergey G Klochkov; Margarita E Neganova; Liudmila M Mikhaleva; Siva G Somasundaram; Cecil E Kirkland; Vadim V Tarasov; Gjumrakch Aliev Journal: Curr Genomics Date: 2020-09 Impact factor: 2.236