Table 1 Subgroup analyses of association between sleep duration and cancer risk
Subgroups | Short sleep duration | Long sleep duration | ||||||
|---|---|---|---|---|---|---|---|---|
n | OR (95% CI) | I2 (%) | PHeterogeneity | n | OR (95% CI) | I2 (%) | PHeterogeneity | |
Regions | ||||||||
USA | 55 | 0.98 (0.95–1.02) | 13.2 | 0.207 | 55 | 1.01 (0.97–1.06) | 7.4 | 0.320 |
Asia | 5 | 1.36 (1.02–1.80) | 58.1 | 0.049 | 5 | 0.75 (0.44–1.27) | 82.0 | <0.001 |
Europe | 4 | 1.19 (0.84–1.67) | 66.7 | 0.029 | 4 | 0.95 (0.64–1.41) | 70.6 | 0.017 |
Gender | ||||||||
Women | 42 | 0.98 (0.94–1.03) | 22.4 | 0.102 | 42 | 1.02 (0.96–1.09) | 30.0 | 0.037 |
Men | 22 | 1.06 (0.96–1.16) | 29.8 | 0.094 | 22 | 1.02 (0.94–1.11) | 33.3 | 0.066 |
Definition of short or long sleep duration | ||||||||
≤ 6 or ≥ 9 | 14 | 1.01 (0.92–1.11) | 44.4 | 0.037 | 54 | 1.01 (0.95–1.06) | 27.7 | 0.034 |
≤ 5 or ≥ 10 | 6 | 1.00 (0.87–1.15) | 51.1 | 0.069 | 7 | 1.14 (0.87–1.49) | 48.7 | 0.069 |
Definition of reference category | ||||||||
7-8 h or 7 h | 51 | 1.00 (0.95–1.05) | 24.6 | 0.061 | 51 | 1.00 (0.95–1.05) | 21.9 | 0.088 |
Definition of short sleep or long duration versus reference category | ||||||||
≤ 6 vs. 7 or ≥ 9 vs. 7 | 9 | 0.98 (0.90–1.07) | 27.0 | 0.204 | 15 | 0.99 (0.90–1.08) | 43.3 | 0.038 |
Study quality score | ||||||||
≥ 7 | 58 | 1.02 (0.97–1.07) | 33.9 | 0.007 | 58 | 1.01 (0.95–1.06) | 32.4 | 0.011 |
< 7 | 7 | 0.97 (0.93–1.02) | 0.00 | 0.627 | 7 | 1.14 (0.95–1.37) | 26.5 | 0.226 |
Cancer type | ||||||||
Sex hormone-related cancers | 22 | 0.99 (0.94–1.04) | 32.9 | 0.069 | 22 | 0.97 (0.89–1.06) | 51.0 | 0.003 |
Breast cancer | 12 | 1.00 (0.94–1.08) | 46.1 | 0.040 | 12 | 1.02 (0.92–1.12) | 51.0 | 0.021 |
Skin cancer | 6 | 0.93 (0.88–1.00) | 0.0 | 0.481 | 6 | 0.92 (0.78–1.10) | 19.4 | 0.287 |
Colorectal cancer | 6 | 1.05 (0.92–1.19) | 38.3 | 0.151 | 6 | 1.21 (1.08–1.34) | 0.0 | 0.555 |
Endometrial cancer | 3 | 0.98 (0.82–1.17) | 44.3 | 0.135 | 3 | 1.06 (0.83–1.34) | 0.0 | 0.589 |
Lung cancer | 5 | 1.04 (0.88–1.22) | 46.1 | 0.115 | 5 | 1.01 (0.83–1.23) | 41.6 | 0.144 |
Ovarian cancer | 3 | 1.05 (0.72–1.53) | 44.3 | 0.166 | 3 | 0.84 (0.46–1.52) | 60.5 | 0.079 |
Prostate cancer | 4 | 0.95 (0.86–1.04) | 0.0 | 0.540 | 4 | 0.75 (0.54–1.05) | 70.9 | 0.016 |
Thyroid cancer | 3 | 1.11 (0.64–1.93) | 65.0 | 0.058 | 3 | 0.95 (0.63–1.45) | 0.0 | 0.539 |