Table 3 Risks of acoustic neuroma in relation to various characteristics of analogue or digital phone use

From: Mobile phone use and risk of acoustic neuroma: results of the Interphone case–control study in five North European countries

  Type of phone a
  Analogue Digital
Factor Cases Controls OR (95% CI) Cases Controls OR (95% CI)
Frequency of use
 Never/nonregular useb 316 1435 1.0 316 1609 1.0
 Regular use 101 414 0.9 (0.7–1.2) 323 1770 0.9 (0.7–1.1)
Years since first use
 Never/nonregular useb 316 1435 1.0 316 1609 1.0
 1.5–4c 10 58 0.5 (0.2–1.1) 208 1157 0.9 (0.7–1.1)
 5–9 48 195 0.9 (0.6–1.3) 113 598 0.9 (0.7–1.2)
10 43 161 1.1 (0.7–1.7) 2 15 0.7 (0.2–3.5)
    P trend=0.8    P trend=0.6
Lifetime years of use
 Never/nonregular useb 316 1435 1.0 316 1609 1.0
 0.5–4 71 279 0.9 (0.7–1.3) 264 1413 0.9 (0.7–1.1)
 5–9 22 107 0.8 (0.5–1.3) 58 348 0.9 (0.6–1.2)
10 7 26 1.1 (0.4–2.8)   2 0 (0-)
 Not known 1 2 P trend=0.7 1 7 P trend=0.5
Cumulative hours of use d
 Never/nonregular useb 316 1435 1.0 316 1609 1.0
 <median 41 204 0.7 (0.5–1.1) 148 867 0.8 (0.7–1.1)
 Median-3rd quartile 21 102 0.7 (0.4–1.2) 80 432 0.9 (0.7–1.2)
 >3rd quartile 35 102 1.3 (0.8–2.0) 88 434 1.0 (0.7–1.3)
 Not known 4 6 P trend=1.0 7 37 P trend=0.7
  1. aOf the 5341 phones listed, for 223 (4.2%) the subject did not recall the model and 130 (2.4%) could not be coded to analogue or digital for other reasons. A total of 248 (10.8%) regular users had used one or more phones that could not be categorised. Repeating the analyses without these 248 subjects produced nearly identical results. For the analogue phone analysis, 260 cases and 1445 controls, and for the digital phone analysis 39 cases and 157 controls were excluded because they were only regular users of all phones combined or only of the digital or analogue type, respectively. A further one case and 259 controls for the analogue phone analysis and 17 controls for the digital phone analysis were excluded because they had no controls or cases, respectively, in their matching stratum.
  2. bReference group is never or nonregular use of mobile phones of any type.
  3. cLower limit 1.5 years ago because regular phone use defined as phone use of at least 6 months’ duration at least 1 year prior to the reference date.
  4. dClassification based on the distribution among controls who were users. Data were divided into <135, 135–493, >493 for analogue phones, and <94, 94–388, >388 for digital phones.