Norwegian women's melanoma risk not raised by outdoor physical activity
Findings from a large population-based study suggest that outdoor physical activity does not raise the risk of cutaneous melanoma in Norwegian women.
In the paper, the authors note that physical activity is an important factor in cancer prevention.
The research sample included 150,000 Norwegian women aged 30 to 75 years who participated in the Norwegian Women and Cancer Study.
Each participant was followed up 18 years after initial survey completion, on average. The women had completed up to three questionnaires about their level of physical activity as well as other topics.
The women who participated in the study registered their level of physical activity on a 10-point scale ranging from “very low” to “very high”. They were also asked how many hours they walked or strolled outdoors, during each of the four seasons.
Participants also registered how many minutes they devoted each day to training/jogging and cycling.
In a press release from the University of Oslo in Norway, where the study was conducted, lead author Flavie Perrier said “We found no increased melanoma risk among physically active women. We even found that the risk of melanoma on the arms was slightly lower among the most active.”
The study findings were published online ahead of print in Preventative Medicine (April 20, 2021).
Perrier is a postdoctoral fellow in the department of biostatistics at the Institute of Basic Medical Sciences at the university.
Senior author Professor Marit Veierød, PhD, said that this finding means that outdoor physical activity can be encouraged, but it is important to remember the advice on sun safety.
“Other studies found that those who were most active got sunburns more often while we found the opposite,” said Dr. Veierød, who is a professor in the same department at the university. “A larger proportion of the most active women did not get sunburns compared to those who were less active,” she explains. “However, physically active women used a solarium more frequently and went on sunbathing vacations more often.”
Perrier mentioned several factors that may have contributed to their findings, and how they differ from other studies in the literature.
“One possible contributory factor is that we live further north, where the UV [ultraviolet] exposure from the sun is different. In addition, our participants were women only, on average older than in the other studies and slightly less active. Not all earlier studies had detailed data on UV exposure. The studies also varied according to whether physical activity was during leisure or work, or a combination of the two.”
“In Norway, many people like to sunbathe in summer. In addition, we have light skin. The high incidence of melanoma in Norway is most probably due to these factors rather than to how active we are,” said Dr. Veierød. “We have a shorter summer season than many other countries and excessive sun exposure may be more common when the opportunity arrives.”
Dr. Veierød emphasized the importance of following medical advice on sun safety and cancer prevention.