Risk Factors

Although many potential predisposing factors for prostate cancer have been investigated, only three risk factors are well-established: age, family history and ethnicity.⁷ The existence of environmental (and therefore potentially modifiable) risk factors for prostate cancer is suggested by the increase in risk observed when migrants move from low-risk to high-risk countries.^5,8 Nonetheless, the exogenous factors explaining this observation have yet to be precisely defined.⁸ Unlike many other tumour types, smoking, alcohol and sedentary lifestyle do not appear to play a role in the development of prostate cancer.⁹

• Age: Prostate cancer is rare before the age of 50, but the incidence increases sharply thereafter, see Figure 4. The mean age at diagnosis is 72–74 years and 85% of cases are identified following the 65th year.⁹ The older the man, the higher his risk of developing prostate cancer.³ 

Figure 4. Average Number of New Cases per Year and Age-Specific Incidence Rates, UK, 2007-2009³

Reproduced with permission from Cancer Research UK

• Family history: People with a family history of prostate cancer in a first-degree relative (i.e. father or brother) have an approximately 2–3-fold increased risk of developing the disease compared with those without affected relatives.^10,11 The risk appears highest if the relative developed prostate cancer at an early age (<60 years), and the presence of multiple affected first-degree relatives confers even greater risk.^10,11 Several candidate susceptibility genes have been identified that may contribute to the inherited predisposition.¹²
• Ethnicity: In the UK the incidence of prostate cancer is around 3-fold higher in black men compared with white men.¹³ In contrast, men of Bangladeshi or Chinese ethnicity living in the UK have significantly lower rates of prostate cancer than white men.¹⁴
• Diet: A body of epidemiological evidence corroborates a ‘Western’ diet enriched in calcium, fat and red meat, and low in fibre, fruit and vegetables as increasing the risk of prostate cancer. There are a number of dietary and nutritional factors that may influence prostate cancer development, these include: include total energy intake (as reflected by body mass index), dietary fat, cooked meat, micronutrients and vitamins (carotenoids, retinoids, vitamins C, D, and E), fruit and vegetable intake, minerals (calcium, selenium), and phyto-oestrogens (isoflavonoids, flavonoids, lignans), or statins and/or cholesterol intake.⁷ Food supplements containing selenium, vitamin E, flavonoids or lycopene are widely used to prevent or treat prostate cancer, although no benefit has been demonstrated.⁹
• Arterial Hypertension: There have been many conflicting studies which demonstrate the association, or lack thereof, between hypertension and prostate cancer. The majority of authors, however, report an increased risk associated with hypertension following both case-control and cohort studies. The Norwegian CONOR study found that prostate cancer, especially those of high histological grade, was associated with hypertension, stating that it could be responsible for 3% of prostate cancers.¹⁵

References