High levels of physical activity were linked with a 22% decreased risk for renal cancer, according to a meta-analysis that looked at results from 19 studies that quantified the relationship with physical activity and renal cancer.
The results of the analysis were published in British Journal of Cancer.
“There are several plausible biologic mechanisms linking a high level of physical activity to reduced renal cancer risk,” said Gundula Behrens, PhD, of the department of epidemiology and preventive medicine at Regensburg University Medical Center, Regensburg, Germany. “Although it is speculative, physical activity may decrease renal cancer risk by reducing unfavorable conditions, such as adiposity, hypertension, insulin resistance, or oxidative stress, factors that are thought to be related to the development of renal cancer.”
Behrens and colleagues identified 19 relevant studies for the meta-analysis. These studies were inclusive of more than 2 million patients and more than 10,000 cases of renal cancer.
When the researchers used a random effects model to summarize the risk estimates for renal cancer from the 19 studies, results indicated that a high level of physical activity resulted in a relative risk for renal cancer of 0.88 (95% CI, 0.79–0.97). By isolating the risk summaries from just those studies deemed to be of high quality, the association between a high level of physical activity and a decreased risk for renal cancer increased (relative risk = 0.78; 95% CI, 0.66–0.92).
Further evaluation of the data revealed that the relative risk of the high-quality studies was not affected by factors such as the type of physical activity assessment, timing in life of physical activity, sex, study design or region, hypertension, smoking, obesity, or diabetes.
The researchers noted that the 19 studies had varying definitions of low and high physical activity, which may have affected the results. This variation meant that no specific “type, intensity, frequency, and duration of physical activity required to lower renal cancer risk” could be identified. Further research will be required to identify this information.
“Our study suggests that renal cancer can be added to the list of cancers potentially preventable by regular physical activity,” Behrens said.
Patients should be encouraged to engage in regular physical activity to reduce the risk of not only renal cancer, but cancer of other sites, such as the colon, breast, and endometrium, where a high level of physical activity has the potential to decrease the risk for cancer, according to Behrens.