One cohort included all adult Danes subscribing for a mobile phone during the period 1982 - 1995 (n=420,095). The other cohort comprised all residents born between 1925 and 1976 with data on sociodemographic factors and cancer risk (n=2.88 million). By linkage of the 2 cohorts via the personal identification number, each of the 2.88 million subjects of the nationwide cohort was classified as either a long-term mobile phone user (by having the first subscription 11 years ago or longer) or non- and shortterm users.
Long-term mobile phone subscription was defined as first subscription 11 years or longer ago.
|Reference group 1||nonusers (no subscription or less than 11 years)|
|Group 2||users with a long-term subscription (first subscription 11 years ago or longer)|
A total of 404 cases in men and 402 cases in women were diagnosed in the cohort as having vestibular schwannoma.
The results of this study including 2.9 million subjects showed that a long-term mobile phone subscription of 11 years and longer was not related to an increased vestibular schwannoma risk in men (RR 0.87 CI 0.52-1.46). No cases among long-term subscribers occurred in women. Vestibular schwannomas did not occur more often on the right side of the head, although the majority of Danes reported holding their mobile phone to the right ear. Tumors in long-term male subscribers were not of larger size than expected.
The authors concluded that overall no evidence was found that mobile phone use is related to the risk of vestibular schwannoma. Because of the usually slow growth of vestibular schwannoma and possible diagnostic delay, further surveillance is indicated.