Epidemiological study (observational study)

Use of wireless phones and the risk of salivary gland tumours: a case-control study epidem.

By: Söderqvist F, Carlberg M, Hardell L

Published in: Eur J Cancer Prev 2012; 21 (6): 576-579

Aim of study (acc. to author)

A case-control study was conducted in Sweden to investigate the association between the use of wireless phones (mobile phones and cordless phones) and the risk of salivary gland tumor.

Further details

In the present publication data were analyzed that were collected in the years after the previous study by Hardell et al. (2004) on the topic had ended.
Participants who started their use of a mobile phone or cordless phone within one year prior diagnosis were classified as unexposed.

Endpoint/type of risk estimation

salivary gland tumor, parotid gland tumor

Type of risk estimation:

incidence

(odds ratio (OR))

Exposure

- mobile communications
- analog mobile phone
- digital mobile phone
- cordless phone

Assessment

questionnaire: use of mobile phones and cordless phones, cumulative number of hours, time since first use, the ear mostly used, use of hands-free equipment
calculation

Exposure groups

Group	Description
Reference group 1	no wireless phone use
Group 2	analog mobile phone, ≤ 52 h, > 1 year latency
Group 3	analog mobile phone, ≤ 52 h, > 1 - 5 year latency
Group 4	analog mobile phone, ≤ 52 h, > 5 - 10 year latency
Group 5	analog mobile phone, ≤ 52 h, > 10 year latency
Group 6	analog mobile phone, > 52 h, > 1 year latency
Group 7	analog mobile phone, > 52 h, > 1 - 5 year latency
Group 8	analog mobile phone, > 52 h, > 5 - 10 year latency
Group 9	analog mobile phone, > 52 h, > 10 year latency
Group 10	digital mobile phone, ≤ 69 h, > 1 year latency
Group 11	digital mobile phone, ≤ 69 h, > 1 - 5 year latency
Group 12	digital mobile phone, ≤ 69 h, > 5 - 10 year latency
Group 13	digital mobile phone, ≤ 69 h, > 10 year latency
Group 14	digital mobile phone, > 69 h, > 1 year latency
Group 15	digital mobile phone, > 69 h, > 1 - 5 year latency
Group 16	digital mobile phone, > 69 h, > 1 - 5 year latency
Group 17	digital mobile phone, > 69 h, > 10 year latency
Group 18	mobile phone, ≤ 66 h, > 1 year latency
Group 19	mobile phone, ≤ 66 h, > 1 - 5 year latency
Group 20	mobile phone, ≤ 66 h, > 1 - 5 year latency
Group 21	mobile phone, ≤ 66 h, > 10 year latency
Group 22	mobile phone, > 66 h, > 1 year latency
Group 23	mobile phone, > 66 h, > 1 - 5 year latency
Group 24	mobile phone, > 66 h, > 5 - 10 year latency
Group 25	mobile phone, > 66 h, > 10 year latency
Group 26	cordless phone use, ≤ 304 h, > 1 year latency
Group 27	cordless phone use, ≤ 304 h, > 1 - 5 year latency
Group 28	cordless phone use, ≤ 304 h, > 5 -10 year latency
Group 29	cordless phone use, ≤ 304 h, > 10 year latency
Group 30	cordless phone use, > 304 h, > 1 year latency
Group 31	cordless phone use, > 304 h, > 1 - 5 year latency
Group 32	cordless phone use, > 304 h, > 5 - 10 year latency
Group 33	cordless phone use, > 304 h, > 10 year latency
Group 34	wireless phone use, ≤ 273 h, > 1 year latency
Group 35	wireless phone use, ≤ 273 h, > 1 - 5 year latency
Group 36	wireless phone use, ≤ 273 h, > 5 -10 year latency
Group 37	wireless phone use, ≤ 273 h, > 10 year latency
Group 38	wireless phone use, > 273 h, > 1 year latency
Group 39	wireless phone use, > 273 h, > 1 - 5 year latency
Group 40	wireless phone use, > 273 h, > 5 -10 year latency
Group 41	wireless phone use, > 273 h, > 10 year latency
Group 42	analog mobile phone use: 1 - 1000 h
Group 43	analog mobile phone use: 1001 - 2000 h
Group 44	analog mobile phone use: > 2000 h
Group 45	digital mobile phone use: 1 - 1000 h
Group 46	digital mobile phone use: 1001 - 2000 h
Group 47	digital mobile phone use: > 2000 h
Group 48	mobile phone use: 1 - 1000 h
Group 49	mobile phone use: 1001 - 2000 h
Group 50	mobile phone use: > 2000 h
Group 51	cordless phone use: 1 - 1000 h
Group 52	cordless phone use: 1001 - 2000 h
Group 53	cordless phone use: > 2000 h
Group 54	wireless phone use: 1 - 1000 h
Group 55	wireless phone use: 1001 - 2000 h
Group 56	wireless phone use: > 2000 h

Population

Group:
- men
- women
Age: 22–80 years
Observation period: 2000 - 2003
Study location: Sweden

Case group

Characteristics: salivary gland tumor
Data source: Regional Oncology Centre of Uppsala/Örebro and Linkoping

Control group

Selection:
- population-based
Matching:
- sex
- area
- 5-year age group
- case:control = 1:4

Study size

	Cases	Controls
Eligible	78	312
Participants	69	262
Participation rate	88 %	83 %

Other:

63 out of 69 patients had parotid gland tumors

Statistical analysis method:

unconditional logistic regression

(adjustment:

sex
socioeconomic status
age at diagnosis, year of diagnosis

)

Results (acc. to author)

36 patients with salivary gland tumor (52%) and 149 control subjects (57%) reported using a wireless phone; mobile phone use (30 cases and 111 controls) was somewhat more common than cordless phone use (19 cases and 93 controls) among both cases and controls.
The use of wireless phones (mobile phones and cordless phones) was not associated with an overall increased risk of salivary gland tumors (OR 0.8; CI 0.4-1.5). There was neither an increased risk for the different phone types when calculated separately nor an increased risk for different latencies or different categories of cumulative use. The overall results were similar for the risk of parotid gland tumors. The authors conclude that their results add the evidence against there being an increased risk for parotid gland tumors associated with light-to-moderate use of wireless phones and for less than 10 years of use.

Study funded by

Cancer och Allergifonden (Cancer and Allergy Foundation), Sweden
Örebro County Council Research Committee, Sweden

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