CHAMGAP
APPROVEDReviewed and approved by the Chamgap Editorial Team (2026-08-05). The draft was written by AI, the existence of all 3 cited sources was verified at the original page, and the verdict passed blind grading and adversarial audit. Methodology v0.6.
Verdict No. 2285 · Search date 2026-08-05 · Methodology v0.6

Indoor tanning-device use,
does it really help with Higher melanoma incidence?

30-Second Summary
B
Evidence Grade B · 79 · Safety warning
Cumulative indoor tanning and early initiation were associated with higher melanoma incidence
Ultraviolet radiation from indoor tanning devices causes burns and photoaging and is associated with higher melanoma incidence. Avoiding cosmetic indoor tanning is the safer choice.
What the
research shows
The grade is B. A prospective cohort followed 141,045 Norwegian women for an average of 13.7 years and documented 861 melanomas. The highest cumulative-use group had 32% higher incidence than never-users, and first use before age 30 was associated with 31% higher incidence. Adjustment included sun behavior and phenotype, but observational data cannot determine each individual's exact causal risk.
What the
ads claim
The endpoint here is melanoma incidence, not mortality. The grade does not rest on an IARC classification label; it rests on the underlying prospective human incidence study.
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Useful facts when choosing a product

  • The cohort included 141,045 women followed for an average of 13.7 years and 1,930,583 person-years.
  • Cancer-registry follow-up identified 861 incident melanomas.
  • The highest cumulative-use tertile and first use before age 30 were each associated with higher incidence than never-use.
  • Models adjusted for sunburn, sunbathing, hair color, skin color, and residence.
Gap Measurement · Verdict 2285 · B 79
What advertising claims
What independent, higher-quality research supports
△ GAP
01

What the research actually shows

Ghiasvand and colleagues followed 141,045 women in the Norwegian Women and Cancer study from 1991 through 2012. Questionnaires repeatedly collected indoor-tanning sessions and age at first use, while a cancer registry identified incident melanoma. Models considered attained age, birth cohort and residence, hair color, skin color, cumulative sunburns, and sunbathing. Direct adjustment for outdoor ultraviolet behavior is a strength, although residual self-report error remains. The exact original funding wording could not be confirmed. Zhang 2012 and Nielsen 2012 share no authors with the cited Ghiasvand team. They are not counted as direct replications because the key estimates and exposure definitions differ and Nielsen's funding wording could not be confirmed. None of the three studies provided exposure-group-specific absolute melanoma incidence.

02

Why this is classified as B (79)

Large prospective enrollment, repeated exposure assessment, a registry endpoint, and adjustment for sun and phenotype support concordant cumulative-use and initiation findings. The decisive evidence remains one observational cohort, giving B with 79 points.

Counterpoint. The association persisted after adjustment, but tanning was not randomized. Exact individual risk can vary with phenotype, device, and outdoor ultraviolet exposure.

Rejudgment record. Cross-check applied — Direct verification of cohort size, follow-up, events, initiation age, cumulative use, and sunlight adjustment

Scoring profile behind this grade
EndpointHHard endpoint - actual events such as death
ReplicationR1Single confirmatory trial
IndependenceI2Decisive evidence is publicly or non-profit funded
Effect sizeE+Meets the clinically important threshold

The scoring table and the verdict agree (B).

Sub-claim grades by effect

This ingredient is marketed for several effects. A single overall grade blends strong and weak claims together, so each effect is graded separately here. The overall grade reflects the strongest disconfirming or core claim.

Effect (sub-claim)GradeBasis
Cumulative indoor tanning and melanoma incidenceBThe highest tertile versus never-use had RR 1.32, 95% CI 1.08-1.63.
First use before age 30 and melanoma incidenceBVersus never-use, RR was 1.31, 95% CI 1.07-1.59.
Indoor tanning and melanoma mortality?This study assessed incidence, not mortality.

Cross-check — Codex and Claude

This verdict was drafted by Codex through literature review and source-existence checks, cross-checked through blind grading and adversarial audit, and settled by reapplying the methodology boundary rules. Cases with split grades were resolved through rejudgment.
03

Evidence Table

StudyDesignSampleFundingEndpointResultWeight
Study 1Prospective population cohort861The exact original funding wording could not be confirmedIncident melanomaHighest cumulative-session tertile RR 1.32 (1.08-1.63); first use before age 30 RR 1.31 (1.07-1.59)Large prospective hard endpoint with sun-behavior and phenotype adjustment
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Receipt — 3 References

All 3 cited sources were verified for existence at the original page (as of 2026-08-05).

Ghiasvand R, Rueegg CS, Weiderpass E, Green AC, Lund E, Veierød MB. Am J Epidemiol. 2017;185(3):147-156. PMID: 28077359. DOI: 10.1093/aje/kww148.
checked
Zhang M, Qureshi AA, Geller AC, Frazier L, Hunter DJ, Han J. J Clin Oncol. 2012;30(14):1588-1593. PMID: 22370316. DOI: 10.1200/JCO.2011.39.3652.
checked
Nielsen K, Måsbäck A, Olsson H, Ingvar C. Int J Cancer. 2012;131(3):706-715. PMID: 21898390. DOI: 10.1002/ijc.26408.
checked
Draft and rewrite: Codex (AI) · Verification: Codex blind grading and adversarial audit · Final adjudication: Claude
Reviewed and approved: Chamgap Editorial Team · Approval date: 2026-08-05 · Corrections: none

Cite this verdict

Indoor tanning-device use x melanoma Evidence Grade B card
[Chamgap] Indoor tanning-device use x melanoma — Evidence Grade B·79. 3 cited sources checked. Source: https://chamgap.com/en/verdicts/skin-hair/indoor-tanning-melanoma-incidence/ · CC BY 4.0

CC BY 4.0 — free to use with attribution; do not distort grades, numbers, or verdict meaning.

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What this document does and does not do

Chamgap is an information source. It reports what research has and has not confirmed; it does not tell readers what to take or buy. That decision belongs to readers and, when needed, medical or legal professionals. This verdict reflects literature available up to the search date and may change as new research appears. Nothing here is medical advice.