People who work outside all day for many years, like gardeners or road workers, are much more likely to get a type of skin cancer called SCC than people who work inside, because of all the sun they’re exposed to.
Scientific Claim
Outdoor workers in Lisbon exposed to cumulative solar ultraviolet radiation (UVR) for 25–40 years have a significantly increased relative risk of developing cutaneous squamous cell carcinoma (SCC), with risk elevations ranging from 65% to over 2,000% depending on occupation and exposure duration, compared to indoor workers with similar recreational UVR exposure.
Original Statement
“Solar UVR exposure was associated with an increased risk of developing SCC by values ranging from 22 to 437%, in terms of individual UVR dose assessment... Pavers had an increased risk of developing SCC by 65%, Asphalters by 133%, Sanitation Workers by 179%, Gravediggers by 187%, and Gardeners by 193%... For 40 years of outdoor work, Sailor: 2,093% increased risk.”
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
association
Can only show association/correlation
Assessment Explanation
The study is observational and uses a modeled risk estimate based on assumptions; it demonstrates association, not causation. The language 'associated with' and 'increased risk' appropriately reflects the evidence level.
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.
Systematic Review & Meta-AnalysisLevel 1aIn EvidenceThe pooled relative risk of SCC among outdoor workers across diverse populations and climates, adjusting for confounders like skin type, sunscreen use, and recreational exposure.
The pooled relative risk of SCC among outdoor workers across diverse populations and climates, adjusting for confounders like skin type, sunscreen use, and recreational exposure.
What This Would Prove
The pooled relative risk of SCC among outdoor workers across diverse populations and climates, adjusting for confounders like skin type, sunscreen use, and recreational exposure.
Ideal Study Design
A systematic review and meta-analysis of 20+ high-quality cohort or case-control studies from Europe, North America, and Australia, including 50,000+ outdoor workers with documented UVR exposure (via dosimetry or validated questionnaires), adjusting for age, skin phototype, history of sunburns, and sunscreen use, with SCC incidence as the primary outcome.
Limitation: Cannot establish biological mechanism or prove causation in individuals.
Prospective Cohort StudyLevel 2aThe prospective incidence of SCC in a defined population of outdoor workers over 10+ years, directly linked to measured UVR exposure and adjusted for confounders.
The prospective incidence of SCC in a defined population of outdoor workers over 10+ years, directly linked to measured UVR exposure and adjusted for confounders.
What This Would Prove
The prospective incidence of SCC in a defined population of outdoor workers over 10+ years, directly linked to measured UVR exposure and adjusted for confounders.
Ideal Study Design
A prospective cohort of 5,000+ outdoor workers (e.g., construction, agriculture, maritime) in Portugal and similar climates, wearing personal UVR dosimeters for 1 year at baseline, followed for 15 years with annual skin exams and biopsy-confirmed SCC diagnosis, adjusting for genetics, sunscreen use, and recreational exposure.
Limitation: Cannot control for behavioral changes over time (e.g., increased sun protection).
Population-Based Case-Control StudyLevel 2bThe odds ratio of SCC among individuals with high occupational UVR exposure compared to matched controls, with exposure quantified by dosimetry or job-exposure matrix.
The odds ratio of SCC among individuals with high occupational UVR exposure compared to matched controls, with exposure quantified by dosimetry or job-exposure matrix.
What This Would Prove
The odds ratio of SCC among individuals with high occupational UVR exposure compared to matched controls, with exposure quantified by dosimetry or job-exposure matrix.
Ideal Study Design
A population-based case-control study of 1,000+ SCC cases and 2,000+ matched controls in Portugal, with UVR exposure estimated via personal dosimetry (≥7 days) and detailed occupational history, controlling for skin type, sunburn history, and indoor/outdoor leisure time.
Limitation: Prone to recall bias in exposure assessment if dosimetry is not used prospectively.
Randomized Controlled TrialLevel 1bWhether reducing occupational UVR exposure through protective interventions directly reduces SCC incidence.
Whether reducing occupational UVR exposure through protective interventions directly reduces SCC incidence.
What This Would Prove
Whether reducing occupational UVR exposure through protective interventions directly reduces SCC incidence.
Ideal Study Design
A cluster-RCT of 50+ construction or landscaping companies (n=10,000+ workers), randomly assigning companies to implement UVR protection (shaded breaks, UV-protective clothing, sunscreen provision) vs. standard care, with SCC incidence tracked over 10 years via dermatological surveillance.
Limitation: Ethically and logistically infeasible to randomize exposure to carcinogens; unlikely to be conducted.
Evidence from Studies
Supporting (1)
This study found that people who work outside in Lisbon—like gardeners and construction workers—have a much higher chance of getting a type of skin cancer called SCC because of too much sun exposure over many years, which matches what the claim says.