Sex Differences in the Association between Night Shift Work and the Risk of Cancers: A Meta-Analysis of 57 Articles
Table 2
The results of subgroup analyses and metaregression analyses on the association between night shift work and the risk of cancers.
Subgroup
No. of studies
Weight (%)
OR (95% CI)
for heterogeneity
for interaction
Shift schedulea
0.570
Rotating shift
29
46.97
1.14 (1.04–1.24)
68.7%
<0.001
Fixed shift
9
11.19
1.09 (0.90–1.31)
51.1%
0.037
Mixed shift
27
41.84
1.20 (0.82–1.77)
80.7%
<0.001
Type of cancerb
0.298
Digestive system cancer
11
15.72
1.15 (1.01–1.32)
40.2%
0.081
Hematological system cancer
5
9.12
1.08 (0.99–1.17)
54.7%
0.066
Prostate cancer
11
16.10
1.26 (1.05–1.52)
73.2%
<0.001
Breast cancer
37
39.62
1.22 (1.08–1.38)
81.2%
<0.001
Reproductive system cancer
6
7.99
1.06 (0.85–1.32)
49.5%
0.078
Lung cancer
5
7.53
1.08 (0.87–1.35)
53.4%
0.073
Skin cancer
3
3.92
0.93 (0.50–1.74)
74.9%
0.019
Region
0.298
Australia
3
5.03
0.91 (0.77–1.06)
0.0%
0.728
Europe
27
48.92
1.18 (1.10–1.28)
75.1%
<0.001
Asia
11
14.29
1.11 (0.88–1.39)
78.3%
<0.001
North America
17
31.75
1.16 (1.04–1.31)
76.1%
<0.001
Occupation
0.795
Unclassified occupation
35
61.45
1.17 (1.10–1.25)
69.7%
<0.001
Industry
9
12.09
1.00 (0.81–1.24)
72.8%
<0.001
Nurses
14
26.46
1.17 (1.02–1.35)
80.6%
<0.001
Study design
0.845
Case-control study
21
32.23
1.28 (1.15–1.42)
66.5%
<0.001
Nested case-control study
6
9.08
1.30 (0.89–1.90)
88.0%
<0.001
Cohort study
31
58.69
1.07 (1.00–1.15)
70.9%
<0.001
Exposure assessment
0.075
Questionnaire
28
53.99
1.08 (1.00–1.17)
77.1%
<0.001
Interview
24
34.52
1.32 (1.17–1.49)
66.3%
<0.001
Database
6
9.06
1.00 (0.85–1.18)
77.1%
0.004
Number of adjusted variables
0.926
≤4
15
22.84
1.13 (0.99–1.28)
82.7%
<0.001
>4
43
77.16
1.16 (1.08–1.24)
72.8%
<0.001
Study score
0.585
Low quality
17
25.20
1.16 (0.98–1.37)
86.9%
<0.001
High quality
41
74.80
1.14 (1.08–1.21)
61.6%
<0.001
a,bFive studies report their studies including different kinds of cancer; nine articles report their studies including different types of shift schedules. values for metaregression.
