How do height, adiposity affect prostate Ca risk?

Taller men and those with greater adiposity are at increased risk of having high-grade prostate cancer and of dying from their malignancy, according to recently published research.

Men who are taller and those with greater adiposity are at increased risk of having high-grade prostate cancer and of dying from their malignancy, according to new analyses of data collected in the European Prospective Investigation into Cancer and Nutrition (EPIC) study.

As reported in a study published in BMC Medicine (2017; 15:115), the investigators analyzed data from 141,896 men enrolled in EPIC, a multicenter cohort study investigating relationships between diet, lifestyle, environmental factors, and cancer risk. Within this population, 7,024 men developed prostate cancer during a mean follow-up of almost 14 years and 934 men died from their prostate cancer.

Multivariable-adjusted models were used to examine associations between height, body mass index (BMI), and waist circumference with prostate cancer risk and death. The prostate cancer risk analyses considered incidence of total prostate cancer and also examined associations with disease aggressiveness by categorizing prostate cancer based on grade (low-intermediate and high) and stage (localized and advanced). For each of the main exposure variables (height, BMI, waist circumference), the men were divided into fifths, and hazard ratios (HRs) were calculated, using the lowest fifth as the reference group.

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Statistically significant positive associations were found between height and both high-grade disease and prostate cancer death. Statistically significant associations between the measures of adiposity and prostate cancer varied by disease aggressiveness. Both BMI and waist circumference were significantly inversely associated with total prostate cancer, low-grade disease, and localized disease, but they were positively associated with high-grade prostate cancer, advanced prostate cancer, and prostate cancer death.

Men in the highest fifth for height had a 1.54-fold increased risk for having high-grade prostate cancer and a 1.43-fold increased risk for prostate cancer death compared with the shortest subgroup. Waist circumference, which may be considered a better marker than BMI for adiposity in men, had slightly stronger associations with the aggressiveness and mortality endpoints than BMI. Men in the highest fifth for waist circumference had a 1.43-fold increased risk for having high-grade prostate cancer and a 1.55-fold increased risk for prostate cancer-related mortality compared with the reference group.

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“The results emphasize the importance of studying risk factors for prostate cancer separately for advanced-stage and high-grade tumors. There is nothing men can do about their height, but at least it is now more evident that they may reduce their risk of aggressive prostate cancer by having a healthy weight. However, further research is still needed to understand possible mechanisms, such as hormonal alterations, and to establish whether the associations we have seen are causal,” said first author Aurora Perez-Cornago, MSc, PhD, of the University of Oxford, Oxford, United Kingdom in a press release from the institution.

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The investigators stated their study had a number of strengths, including its prospective design, long duration of follow-up, large population and number of incident prostate cancer cases, and availability of data on potential confounders, tumor characteristics, and prostate cancer-related death. Among its limitations were missing information on tumor characteristics for about one-fourth of the men with prostate cancer and lack of data on early-life factors that could affect prostate cancer risk.

Putting their findings into perspective, the investigators noted that previous studies have reported a positive association between height and death from prostate cancer and between adiposity and risk of aggressive disease. The identification of an inverse association between adiposity and prostate cancer incidence and non-aggressive disease was also consistent with previous reports. However, the present study is thought to be the first to identify height as a risk factor for high-grade prostate cancer.

Mechanisms for the observed associations with the body size factors were also discussed.