May 3, 2021
Cancer center researchers Xin Li, Sc.D., and Jiali Han, Ph.D., served as senior authors of “The Association between Citrus Consumption and Melanoma Risk in the UK Biobank,” which was published in BJD, the British Journal of Dermatology.
They and their colleagues concluded that high citrus consumption is associated with an increased risk of melanoma and that further validation of their findings could lead to improved melanoma prevention strategies.
Li
The study builds upon research that Han and others published in the Journal of Clinical Oncology in 2015 in which the authors reported similar findings.
Li answered questions about the study published in BJD.
In your words, what is the single main purpose of this study?
Psoralen, a known photocarcinogen, is naturally abundant in citrus products, leading to the hypothesis that high citrus consumption may increase melanoma risk. This fairly new hypothesis has yielded inconsistent results from previous studies, which represents a critical gap in the melanoma knowledge base and highlights the need for further investigation of citrus as a potential melanoma risk factor.
The purpose of the current study is to address these gaps in knowledge by performing the following analyses in the UK Biobank, a large population-based cohort: 1.) investigate the association between total citrus consumption and melanoma risk; 2.) investigate the association between individual citrus product and melanoma risk; and 3.) test for interactions between total citrus intake and established melanoma risk factors.
What were the key findings/results?
We found that individuals who consume more citrus are at higher risk of melanoma compared to those with no consumption. Among the individual citrus products examined, consumption of oranges and orange juice are positively associated with melanoma risk. We also observed that the association for total citrus is modified by skin color: Participants with a fair or very fair skin complexion were found to be particularly at risk with higher citrus intake.
What is the significance of the finding? Is it new? Does it confirm anything?
Since 2015, three large prospective studies in the United States have investigated the hypothesis that high citrus consumption increases melanoma risk due to psoralen photocarcinogenicity. These studies have yielded mixed results, and they were subject to limitations that could challenge external validity.
In the current study among the UK population, we confirm the positive association between total citrus consumption and melanoma reported by a previous U.S. study. To the best of our knowledge, this association has been investigated for the first time in a British cohort.
We believe the results of the study will increase current knowledge and understanding of skin cancer risk factors, and, upon further validation, can serve as an empirical basis for future primary prevention interventions.
What are the strengths of your study?
Using data from the UK Biobank, a large prospective cohort with rich information, we were able to include more than 190,000 people in the current analysis and control for key sociodemographic and skin cancer-related variables. We also investigated how pigmentation phenotypes and sun exposure history might influence the association of interest.
What are the implications of your findings? Are there clinical applications that can be applied in the next few years?
Further investigation and confirmation of these findings could lead to improved melanoma risk-reduction strategies. Research on this topic could help physicians/clinicians better advise their patients to prevent melanoma skin cancer.
Initially, will your study be of most interest to other researchers? The general public?
This information will be particularly useful to cancer researchers, clinicians, and anyone interested in the primary prevention of melanoma. Individuals who like to eat citrus fruit and already have established risk factors of skin cancer, such as family history of melanoma and fair skin cancer, may consider reducing their citrus intake. Citrus has a beneficial health effect as it’s high in vitamin C and other phytonutrients. We are not concerned about citrus products. However, people who consume a lot of citrus may consider taking extra sun protections.
All of the study’s authors are connected to IU: Li, Han, and Yiqing Song, M.D., Sc.D., are faculty at the IU Richard M. Fairbanks School of Public Health at IUPUI. Victoria Champion, Ph.D., is associate director of community outreach and population science research at the IU Simon Comprehensive Cancer Center and is a faculty member at IU School of Nursing; Ming Li, Ph.D., is a faculty member at IU School of Public Health-Bloomington; and Andrew Marley, Ph.D., a former student in the National Cancer Institute-funded T32 Interdisciplinary Training in Behavioral Oncology program at IU, graduated last year from the Fairbanks School of Public Health’s Department of Epidemiolgy.
