Table 3

Odds ratios and 95% confidence intervals for risk of glioma in relation to use of analogue phones

Factor and level of exposureCasesControlsOdds ratio (95% CI)
Frequency of use*:
Never/non-regular456 (47.2)818 (47.7)1.0
Digital only378 (39.1)685 (39.9)0.96 (0.79 to 1.16)
Regular analogue128 (13.3)212 (12.4)0.87 (0.66 to 1.15)
Not known4 (0.4)1 (0.1)
Years since first use:
Never/non-regular456 (47.2)818 (47.7)1.0
Digital only378 (39.1)685 (39.9)0.96 (0.79 to 1.16)
1.5-415 (1.6)33 (1.9)0.59 (0.30 to 1.15)
5-956 (5.8)84 (4.9)0.98 (0.66 to 1.45)
≥1056 (5.8)95 (5.5)0.87 (0.59 to 1.27)
Not known5 (0.5)1 (0.1)
Lifetime years of use:
Never/non-regular456 (47.2)818 (47.7)1.0
Digital only378 (39.1)685 (39.9)0.96 (0.79 to 1.16)
0.5-490 (9.3)159 (9.3)0.82 (0.60 to 1.11)
5-927 (2.8)42 (2.4)0.97 (0.57 to 1.66)
≥1010 (1.0)11 (0.6)1.20 (0.48 to 3.04)
Not known5 (0.5)1 (0.1)
Cumulative hours of use ≥10 years ago:
Never/non-regular456 (47.2)818 (47.7)1.0
Digital only378 (39.1)685 (39.9)0.95 (0.79 to 1.16)
<10 years69 (7.1)115 (6.7)0.86 (0.61 to 1.22)
≥10 years, ≤126 hours23 (2.4)47 (2.7)0.70 (0.41 to 1.21)
≥10 years, >126 hours31 (3.2)47 (2.7)0.98 (0.59 to 1.62)
Not known9 (0.9)4 (0.2)
  • * Of 4055 phones reported by participants, 586 (14.5%) were analogue, 3183 (78.5%) were digital, and 286 (7.1%) could not be classified.

  • † Lower limit 1.5 years ago because regular phone use defined as phone use of at least six months' duration at least one year before reference date.

  • ‡ Use ≥10 years before reference date for controls and diagnosis date for cases.