Time trends in mobile phone use and glioma incidence among males in the Nordic Countries, 1979-2016

Environment International. · 2022 · No effect · Moderate evidence

← Research stream

No effectModerate evidencePaper 729

Glioma incidence rates among males aged 40-69 in Nordic countries increased slightly and steadily from 1979 to 2016, but observed trends were incompatible with moderate or higher risk increases reported in some case-control studies. The study found no evidenc…

Study snapshot

PublicationEnvironment International. · 2022

Study typeecological

Reported directionNo effect

Evidence ratingModerate

Abstract

Time trends in mobile phone use and glioma incidence among males in the Nordic Countries, 1979-2016 Isabelle Deltour, Aslak Harbo Poulsen, Christoffer Johansen, Maria Feychting, Tom Børge Johannesen, Anssi Auvinen, Joachim Schüz. Time trends in mobile phone use and glioma incidence among males in the Nordic Countries, 1979-2016. Environment International. 2022. 107487. doi:10.1016/j.envint.2022.107487. Abstract Introduction In the Nordic countries, the use of mobile phones increased sharply in the mid-1990s especially among middle-aged men. We investigated time trends in glioma incidence rates (IR) with the perspective to inform about the plausibility of brain tumour risks from mobile phone use reported in some case-control studies. Methods We analysed IR of glioma in Denmark, Finland, Norway, and Sweden among men aged 40-69 years, using data from national cancer registries and population statistics during 1979-2016, using log-linear joinpoint analysis. Information on regular mobile phone use and amount of call-time was obtained from major studies of mobile phones in these countries. We compared annual observed incidence with that expected under various risk scenarios to assess which of the reported effect sizes are compatible with the observed IR. The expected numbers of cases were computed accounting for an impact of other factors besides mobile phone use, such as improved cancer registration. Results Based on 18,232 glioma cases, IR increased slightly but steadily with a change of 0.1% (95%CI 0.0%, 0.3%) per year during 1979-2016 among 40–59-year-old men and for ages 60-69, by 0.6 % (95%CI 0.4, 0.9) annually. The observed IR trends among men aged 40-59 years were incompatible with risk ratios (RR) 1.08 or higher with a 10-year lag, RR ≥ 1.2 with 15-year lag and RR ≥ 1.5 with 20-year lag. For the age group 60-69 years, corresponding effect sizes RR ≥ 1.4, ≥ 2 and ≥ 2.5 could be rejected for lag times 10, 15 and 20 years. Discussion This study confirms and reinforces the conclusions that no changes in glioma incidence in the Nordic countries have occurred that are consistent with a substantial risk attributable to mobile phone use. This particularly applies to virtually all reported risk increases reported by previous case-control studies with positive findings. Excerpts "Our analyses are based on 18,232 male glioma cases, which occurred in the male population aged 40-69 years in Denmark, Finland, Norway and Sweden with 162 million person-years at risk. Rates of glioma showed a slow and constant increase with no marked changes in the trend in the recent years." "... our study also has some limitations. The exposure prevalence was obtained from two sources with different recruitment methods, age and questionnaire characteristics; the prevalence in the age group 60-69 years was less accurately registered than for the age group 40-59 years, because both studies had small sample sizes in this age range at recruitment, and in addition, the data had to be extrapolated for the distant past. Therefore, using these estimates of exposure prevalence could at best provide a range of possible exposure distributions in the population. The use of hands-free devices was not accounted for, but this was not frequent in these populations (data not shown). Our study is not free of assumptions. The induction period for an effect of mobile phone use on glioma risk, if one exists, is unknown, as is the magnitude of the risk, if any, and the real patterns may be more complex than the scenarios that we simulated. In addition, there are several factors that we were not able to account for. The coverage of the Nordic cancer registries was not perfectly complete, some 1.5% to 10% of the malignant brain tumours were missed in these age groups, but there is no reason to believe this proportion has increased over time. In Sweden, it has been estimated that completeness would not have changed over the period 1998-2014 for the age group 20-69 years, but has increased among ≥70 year olds; completeness might have improved in the other countries due to introduction of automated registration routines (Tettamanti et al., 2019, Gjerstorff, 2011, Leinonen et al., 2017, Larsen et al., 2009). Our analyses incorporated the possibility that other, currently unknown, risk factors, as well as improvement in glioma detection and reporting had a smooth, gradual impact, over the period 1979−2016, consistent with the gradually increasing IRs." "Our findings indicate that glioma incidence trends among men aged 40-59 years in the Nordic countries are not consistent with increased risks of moderate effect size (RR>1.2-1.4) assuming latency up to 20 years. This means that increased risks reported in some case-control studies are implausible and likely attributable to biases and errors in self-reported use of mobile phone. Our results were consistent with results from prospective cohort studies showing no association between mobile phone use and risk of glioma. Funding: This study was supported by the German Federal Office for Radiation Protection (BfS; grant FM 8867)." sciencedirect.com

Machine Enhanced Logic

AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeecological

Effect directionno_effect

Populationmales aged 40-69 years in Denmark, Finland, Norway, and Sweden

Sample size18232

ExposureRF

Evidence strengthModerateConfidence: 80% · Peer reviewed: yes

Main findings

Outcomes measured

glioma incidence rates

Limitations

Exposure prevalence estimates were based on limited and extrapolated data with small sample sizes in older age groups.
Use of hands-free devices was not accounted for but considered infrequent.
Assumptions about induction period and risk magnitude may not capture complex real patterns.
Cancer registry coverage was not perfectly complete and may have improved over time.
Potential unknown risk factors and improvements in detection/reporting were modeled as smooth gradual impacts.

View raw extracted JSON

{
  "study_type": "ecological",
  "exposure": {
    "band": "RF",
    "source": "mobile phone",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": "males aged 40-69 years in Denmark, Finland, Norway, and Sweden",
  "sample_size": 18232,
  "outcomes": [
    "glioma incidence rates"
  ],
  "main_findings": "Glioma incidence rates among males aged 40-69 in Nordic countries increased slightly and steadily from 1979 to 2016, but observed trends were incompatible with moderate or higher risk increases reported in some case-control studies. The study found no evidence supporting a substantial glioma risk attributable to mobile phone use.",
  "effect_direction": "no_effect",
  "limitations": [
    "Exposure prevalence estimates were based on limited and extrapolated data with small sample sizes in older age groups.",
    "Use of hands-free devices was not accounted for but considered infrequent.",
    "Assumptions about induction period and risk magnitude may not capture complex real patterns.",
    "Cancer registry coverage was not perfectly complete and may have improved over time.",
    "Potential unknown risk factors and improvements in detection/reporting were modeled as smooth gradual impacts."
  ],
  "evidence_strength": "moderate",
  "confidence": 0.8,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "mobile phone",
    "glioma",
    "incidence",
    "Nordic countries",
    "ecological study",
    "brain tumor",
    "radiofrequency"
  ],
  "suggested_hubs": [
    {
      "slug": "rf-exposure",
      "weight": 0.9,
      "reason": "Study focuses on mobile phone RF exposure and brain tumor incidence."
    }
  ]
}

AI can be wrong. Always verify against the paper.

AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1016/j.envint.2022.107487
PubMed: Not supplied

Read the original paper →

Related papers

← Back to the Research Library