Study type: Epidemiological study (observational study)

Cellular phone use and risk of benign and malignant parotid gland tumors--a nationwide case-control study. epidem.

Published in: Am J Epidemiol 2008; 167 (4): 457-467

Aim of study (acc. to author)

The association between cellular phone use and parotid gland tumors was investigated in a nationwide case-control study in Israel. This study is part of the INTERPHONE project.

Further details

The association between laterality of tumor and side of cellular phone use was assessed by case-only analysis (including only cases who were regular users reporting on a single dominant side of use) and by case-control analysis stratified to ipsilateral and contralateral use.
Regular use of a mobile phone was defined as at least once a week for at least six months.

Endpoint/type of risk estimation

Type of risk estimation: (odds ratio (OR))

Exposure

Assessment

Exposure groups

Group Description
Reference group 1 regular user: no or < 1year
Group 2 regular user: yes
Reference group 3 regular user 5 years in the past: no
Group 4 regular user 5 years in the past: yes
Reference group 5 regular user 10 years in the past: no
Group 6 regular user 10 years in the past: yes
Reference group 7 time since start use: never or < 1 year
Group 8 time since start use: 1 - 4.9 years
Group 9 time since start use: 5 - 9.9 years
Group 10 time since start use: ≥ 10 years
Reference group 11 duration of use: never or < 1 year
Group 12 duration of use: 1 - 4.9 years
Group 13 duration of use: 5 - 9.9 years
Group 14 duration of use: ≥ 10 years
Reference group 15 cumulative number of calls: nonusers or < 1 year
Group 16 cumulative number of calls: ≤ 5,479
Group 17 cumulative number of calls: ≥ 5,480
Group 18 cumulative number of calls: ≥ 18,997
Reference group 19 cumulative call time: nonusers or < 1 year
Group 20 cumulative call time: ≤ 266.3 hours
Group 21 cumulative call time: > 266.3 hours
Group 22 cumulative call time: > 1,035 hours
Reference group 23 cumulative call time by time since start use: nonusers or < 1 year
Group 24 cumulative call time by time since start use: < 5 years, ≤ 266.3 hours
Group 25 cumulative call time by time since start use: < 5 years, > 266.3 hours
Group 26 cumulative call time by time since start use: ≥ 5 years, ≤ 266.3 hours
Group 27 cumulative call time by time since start use: ≥ 5 years, > 266.3 hours
Reference group 28 cumulative number of calls by time since start use: nonusers or < 1 year
Group 29 cumulative number of calls by time since start use: < 5 years, ≤ 5479
Group 30 cumulative number of calls by time since start use: < 5 years, > 5479
Group 31 cumulative number of calls by time since start use: ≥ 5 years, ≤ 5479
Group 32 cumulative number of calls by time since start use: ≥ 5 years, > 5479
Reference group 33 regular users only, time since start use: 1 - 4.9 years
Group 34 regular users only, time since start use: 5 - 9.9 years
Group 35 regular users only, time since start use: ≥ 10 years
Reference group 36 regular users only, duration of use: 1 - 4.9 years
Group 37 regular users only, duration of use: 5 - 9.9 years
Group 38 regular users only, duration of use: ≥ 10 years
Reference group 39 regular users only, cumulative number of calls: ≤ 5,479
Group 40 regular users only, cumulative number of calls: 5,480 - 18,996
Group 41 regular users only, cumulative number of calls: ≥ 18,997
Reference group 42 regular users only, cumulative call time: ≤ 266.3 hours
Group 43 regular users only, cumulative call time: 266.4 - 1034.9 hours
Group 44 regular users only, cumulative call time: ≥ 1035 hours

Population

Case group

Control group

Study size

Cases Controls
Eligible 531 1,920
Participants 460 1,266
Participation rate 87 % 66 %
Other:

402 benign and 58 malignant tumors

Statistical analysis method: (adjustment: )

Conclusion (acc. to author)

Cellular phone users in Israel are exceptionally heavy users compared to cellular phone users in other countries participating in the Interphone study.
No increased risk of parotid gland tumors was observed for ever having been a regular cellular phone user for the entire group. For ipsilateral use, the odds ratios in the highest category of cumulative number of calls and call time were significantly elevated.
The authors concluded that the results suggest a relation between long-term and heavy cellular phone use and parotid gland tumors. This association was seen in analyses restricted to regular users, analyses of laterality of cellular phone use, and analyses of area of main use (urban, rural, or both) .

Study funded by

Related articles