Jessica Gorzelitz

Ph.D., M.S.

NCI / DCEG / MEB

Cancer prevention postdoctoral fellow

PLCO (Learn more about this study)

PLCO-665

Sep 10, 2020

Characteristics associated with weightlifting, cancer risk and associated mortality

The physical activity guidelines recommend muscle strengthening activity (MSA, also known as resistance or strength training) for the whole body on at least 2 days per week [1]. These recommendations are provided to maximize health benefits such as lower risk of chronic diseases and reduced mortality [1]. Most epidemiologic associations of physical activity and cancer incidence have examined aerobic activity, with limited studies examining MSA. In a pooled analysis, moderate to vigorous intensity (aerobic) activity was linked to a lower risk of developing 13 types of cancer, including endometrial cancer [2]. Mazzilli et. al recently published using the AARP cohort data showing MSA was associated with a lower risk of colon cancer, however only ten cancer types were studied, excluding all gynecologic malignancies [3].

Most studies show that aerobic exercise reduces risk of mortality in adults [4]. Those studies isolating MSA as an exposure have found lower risks of mortality in healthy adults [5, 6] and in cancer survivors specifically [7]. However, these associations have not been consistent across studies, as some report no association with MSA [4, 6]. In gynecologic cancer survivors specifically, observational data has been mixed about the impact of self-reported physical activity on mortality [8, 9]. To date, no studies have examined the independent association of MSA on mortality in gynecologic cancer survivors.
The epidemiologic evidence base for weightlifting and cancer is very scant, including very limited evidence on the characteristics of those who participate in weightlifting behaviors. Only three publications to date (Bennie 2016, Bennie 2018 and Bennie 2020**) have published on the characteristics of those who report weightlifting from epidemiologic studies, and these publications used population-based studies which were not specific to cancer. Understanding the demographics and characteristics (i.e. age, marital status, education, smoking, health history) of those who report weightlifting is a necessary first step in this analysis to represent the causal framework appropriately. Once we can better describe the patterns of those who are engaged in this activity, we will then expand the analysis into weightlifting and cancer risk, then weightlifting and mortality. A special emphasis will be placed on gynecologic malignancies, however given that the evidence base is so limited, it is necessary to describe the relationship between weightlifting and cancer risk and mortality for all cancers before focusing on gynecologic cancers.

The data from the PLCO cohort will be merged with that from the NIH-AARP cohort study to increase study power. Both cohorts have measures of weightlifting/MSA and cancer survivors.

1. Identify and describe the demographic and behavioral characteristics associated with those who report weightlifting activity.
2. Determine if weightlifting is associated with risk of cancer. This includes an overall association for all cancers and site-specific disease. Special emphasis will be placed on gynecologic malignancies (endometrial and ovarian).
3. Determine if weightlifting is associated with reduced mortality (all-cause, cancer-specific and cardiovascular-disease specific)

**new references: Bennie, J. A., Pedisic, Z., van Uffelen, J. G., Charity, M. J., Harvey, J. T., Banting, L. K., ... & Eime, R. M. (2016). Pumping iron in Australia: prevalence, trends and sociodemographic correlates of muscle strengthening activity participation from a national sample of 195,926 adults. PLoS One, 11(4), e0153225. | Bennie, J. A., Lee, D. C., Khan, A., Wiesner, G. H., Bauman, A. E., Stamatakis, E., & Biddle, S. J. (2018). Muscle-strengthening exercise among 397,423 US adults: prevalence, correlates, and associations with health conditions. American Journal of Preventive Medicine, 55(6), 864-874. | Bennie, J. A., Kolbe-Alexander, T., Seghers, J., Biddle, S. J., & De Cocker, K. (2020). Trends in Muscle-Strengthening Exercise Among Nationally Representative Samples of United States Adults Between 2011 and 2017. Journal of Physical Activity and Health, 17(5), 512-518.