Natural Hair Color Identified as Potential Skin Cancer Risk Factor

There may be a correlation between natural hair color and skin cancer, according to a study published in Gene.

Samples of Different Hair Colors | image credit: Margo_Alexa - stock.adobe.com

Skin cancer is typically identified in 2 categories: keratinocyte skin cancer (KSC) and melanoma. The prevalent subtypes of KSC are squamous cell carcinoma (SCC) and basal cell carcinoma (BCC); however, cutaneous melanoma (CM) is indicated to have higher rates of mortality in affected patients. As metastasis in CM further complicates a patient’s chances of survival, there is a need for earlier diagnostic strategies based on risk factors for CM.

Risk factors such as fairer skin, using tanning beds, family history, prior experience with skin cancer, sun burns, and even freckles have been indicated as contributors to one’s vulnerability to skin cancer. Furthermore, natural hair color has become a risk factor of interest. The authors of the present study cite prior research that associates red hair, blonde hair, and darker hair with certain increases in skin cancer risk. At present, however, the relationship between hair color and risk is not completely clear and this data have largely been derived from observational studies without validation from randomized controlled trials (RCTs).

To combat the potentially biased and time- and cost-consuming nature of observational studies and RCTs, researchers utilized a Mendelian randomization to investigate whether a risk factor for skin cancer can be linked to some form of genetic variation in natural hair color. Their assessment included a diverse set of genetic variants (instrumental variables [IVs]) to paint a clearer picture about any potential influence natural hair color has on the development of skin cancers.

Data were gathered from a meta-analysis from the UK Biobank Consortium that included 360,270 individuals descendent from Europe. A total of 211 single nucleotide polymorphisms were used as genetic instruments in their analysis.

Higher risk of CM was associated with red hair (OR, 1.034; 95% CI, 1.024-1.044; P < .001), blonde hair (OR, 1.008; 95% CI, 1.003-1.014; P = .003), and light brown hair (OR, 1.006; 95% CI, 1.002-1.011; P = .009). Individuals with dark brown hair exhibited a decreased risk compared with light-haired individuals (OR, 0.987; 95% CI, 0.984-0.990; P < .001), whereas those there was no noted association between CM risk and black hair.

In a similar trend, the risk of KSC was higher in those with red hair (OR, 1.078; 95% CI, 1.053-1.103; P < .001), blond hair (OR, 1.024, 95% CI, 1.009-1.040; P = .002), and light brown hair (OR, 1.018; 95% CI, 1.004-1.033; P = .01). Dark brown hair was shown to have a negative association with KSC (OR, 0.979; 95% CI, 0.970-0.988; P < .001), as was black hair (OR, 0.954; 95% CI, 0.913-0.997; P = .036).

A secondary MR analysis replicated these results but revealed a gender-specific complexity regarding skin cancer risk and hair color. Notably, the risk of KSC was observably higher in men with red hair (P = .032) and blonde hair (P = .036). Women with red hair were also more impacted by KSC (P < .001). These analyses also further demonstrated the apparent protective effect of dark brown hair on KSC risk across genders (P = .002).

As these results have identified individuals with lighter hair as carrying more risk for skin cancer development, the authors conclude by emphasizing the importance of earlier prevention methods, such as sun avoidance or protection. Furthermore, it could be beneficial to implement earlier cancer screenings for those with lighter hair. Earlier detection and prevention are of utmost importance because, as the authors note, previous research has suggested that earlier detection of CM can lead to better treatment access in 90% of cases.

Reference

Wang S, Chen J, Jin Z, Xing Y, Wang R. Natural hair color and skin cancers: a two-sample Mendelian randomization study. Gene. 2024;893:147940. doi:10.1016/j.gene.2023.147940