Researchers from QIMR Berghofer have uncovered new evidence that explores the trend that people with hair loss can be more susceptible to deadly skin cancers.
Their findings are published in the journal Nature Communications.
In a press release, lead researcher Jue-Sheng Ong, PhD, said they were particularly interested in whether the link was driven by testosterone or sun exposure.
“Testosterone levels are a major driver of male pattern baldness, and some studies suggest they may also contribute to this increased skin cancer risk in people with hair loss,” said Dr. Ong.
Dr. Ong is a research officer in the Statistical Genetics group (MacGregor lab) in the QIMR Berghofer Medical Research Institute in Herston, Australia.
“The more obvious explanation would be that people with hair loss receive greater sun exposure to their head and neck.
“We sought to find clear answers, and unsurprisingly, it appears the more common-sense explanation is the correct one. Balding men are more susceptible to sun damage and skin cancer because they have less hair protection.”
In the release, the study authors say that while the explanation may seem self-evident, the research team needed to run extensive genetic analyses to provide evidence-based insight into the relationship between baldness and skin cancer.
“It's important that we investigate and prove causality to inform the best evidence-based prevention for deadly skin cancers—even if the answers seem obvious," said senior researcher Matthew Law, PhD.
“Health programs and interventions cannot be guided by assumptions. They need to be backed by evidence if they're to work.”
Dr. Law is a statistical geneticist and bioinformatician in the Statistical Genetics Laboratory at QIMR Berghofer.
The researchers analyzed genetic data from more than 29,000 cases of melanoma and keratinocyte cancer, available from the landmark QSkin Study and Melanoma Institute Australia.
They also incorporated large-scale genetic findings on testosterone and hair loss, to establish whether genes that predispose people to high testosterone or balding affect skin cancer risk.
The analysis confirmed a strong link between balding and skin cancers, that the link was predominantly due to greater sun exposure. However, genes linked to hair loss and skin colour also appear to play a role.
“We found no evidence that testosterone levels play any meaningful role in the relationship between balding and skin cancer,” said Dr. Ong.
“Interestingly, we did find an overlap between genes which cause hair loss and genes which affect skin colour or pigmentation. Skin colour is a known risk factor for skin cancer, and these results suggest pigmentation may also contribute to this increased risk in people with hair loss.
“However, the majority of this relationship between balding and skin cancer is still explained by increased sun exposure.”
The genetic findings were supported by further analysis of skin cancers in people with hair loss, categorized by anatomical region. It found that balding is associated with an elevated risk of developing skin cancers in the head and neck region, as people with hair loss are likely to receive more sun exposure around these body parts.