Factor N (%)a
reporting		 N shown
significant
association
Age
12 (24.5)
3
Gender
13 (26.5)
3
Socio-demographic factors
Education
Employment status
Income
Ethnicity
Marital status
2 (4.1)
2 (4.1)
1 (2)
1 (2)
2 (4.1)
-
1
1
1
1
Alcohol consumption
3 (6.1)
1
Smoking
2 (4.1)
-
Other factors
Co-morbidity
Metallic taste
Prognosis
Dental care
Depression or anxiety
Optimism
2 (4.1)
1 (2)
2 (4.1)
1 (2)
5 (10.2)
1 (2)
-
1
2
-
5
1
Site of cancer 10 (20.4)
5
Tumour stage 11 (22.4)
5
Tumour size 3 (6.1)
1
Treatment-related factors
Type of treatment
24 (49)
15
Stage of treatment or time since treatment
9 (18.4)
6

aNumbers do not add up to total (n = 49), because some studies reported several factors.