"Gay and bisexual men 'more likely to suffer skin cancer' – and it may be because they use sunbeds more, scientists say," reports the Mail Online.
A survey of 845,264 men and women in the US found that men who said they were gay or bisexual were more likely to have been diagnosed with skin cancer than straight (heterosexual) men. Women who said they were lesbian, gay or bisexual were equally or less likely to have been diagnosed with skin cancer compared to straight women.
The survey did not ask questions about whether people sunbathed or used sunbeds, so we do not know why gay and bisexual men were more at risk. But the researchers say previous studies have found more gay and bisexual men use sunbeds, so that is a possible explanation for the difference.
Where did the story come from?
The researchers who carried out the study are from Harvard Medical School in the US.
The study was published in the peer-reviewed journal JAMA Dermatology. No information about funding was provided.
The Mail Online article was clear about the limits of the study and presented an accurate summary of the findings.
What kind of research was this?
This was a cross-sectional population survey, using information from an annual survey of adults in the US (the Behavioural Risk Factor Surveillance System, BRFSS).
This type of study is useful to compare risks of conditions between groups of individuals, but it does not tell us the causes of any differences in risks.
What did the research involve?
Researchers used information about 845,264 people who took part in the BRFSS between 2014 and 2018, and who gave information about their sexual orientation and whether they had been diagnosed with skin cancer. The survey asked these questions of adults in 37 US states.
They worked out the lifetime chance of having skin cancer (adjusted for age) for the following groups:
- men who said they were gay
- men who said they were bisexual
- men who said they were straight
- women who said they were gay or lesbian
- women who said they were bisexual
- women who said they were straight
They then adjusted their results for potential confounding factors including:
- people's age
- the region where they lived
- ethnic background
- health insurance status
- if they drank alcohol or smoked
- if they had been diagnosed with any other type of cancer
They calculated the odds of having skin cancer for gay or bisexual men compared to straight men, and for lesbian, gay or bisexual women compared to straight women.
What were the basic results?
Of the men in the study:
- 6.7% of straight men had skin cancer
- 8.1% of gay men had skin cancer
- 8.4% of bisexual men had skin cancer.
This represented a 26% increased risk of skin cancer for gay men and a 48% increased risk of skin cancer for bisexual men (adjusted odds ratio [aOR] for gay men 1.26, 95% confidence interval [CI] 1.05 to 1.51; aOR for bisexual men 1.48, 95% CI 1.02 to 2.16).
Of the women in the study:
- 6.6% of straight women had skin cancer
- 5.9% of lesbian or gay women had skin cancer
- 4.7% of bisexual women had skin cancer
This represented a 22% lower risk of skin cancer for bisexual women compared to straight women (aOR 0.78, 95% CI 0.61 to 0.99). The difference between rates for straight and lesbian or gay women was too small to be sure it was not down to chance (aOR 0.97, 95% CI 0.73 to 1.27).
How did the researchers interpret the results?
The researchers said this was the "largest study to examine lifetime prevalence of skin cancer among sexual minorities". They said the higher risk found among gay and bisexual men showed that "patient education and community outreach initiatives focused on reducing skin cancer risk behaviours among sexual minority men may help reduce lifetime development of skin cancer in this population."
They added that the findings showed the importance of asking about sexual orientation in health surveys, as it can identify groups at higher risk of certain conditions.
This study is quite limited, because we do not know why people's risk of skin cancer in the study varied according to sexual orientation. It may be, as the authors suggest, that attitudes to safe sun and use of sunbeds vary between groups. But the survey did not ask questions about sunbed use, so we do not know.
It is worth noting that people were not formally diagnosed with skin cancer in the study but were asked if they had been told by a doctor or nurse that they had skin cancer. This could make the results less accurate.
It seems unlikely that sexual orientation itself changes the risk of skin cancer, so it is possible that people's behaviour affects risk. But there are other factors, aside from sunbed use, that could affect people's chances of a skin cancer diagnosis, such as:
- skin type, including how easily people get sunburned
- job, for example whether people work indoors or outdoors
- if they have HIV – if a person's immune system is weakened by HIV, they are at higher risk of cancers, including skin cancer
- use of sun protection
- ability to access healthcare – people in the US who are not insured or have lower health insurance may be less likely to visit a doctor and have cancer diagnosed
It is also worth remembering that the differences in risk between the various groups are not very big, and that everyone is at risk of skin cancer if they do not protect their skin in the sun. You should spend time in the shade when the sun is strongest. In the UK, this is between 11am and 3pm from March to October.
Advice is to:
- make sure you never burn
- cover up with suitable clothing and sunglasses
- take extra care with children
- use at least factor 30 sunscreen
Analysis by Bazian
Edited by NHS Website
Links to the headlines
Mail Online, 12 February 2020
Links to the science
JAMA Dermatology. Published online 12 February 2020