Consumption of Fish Products across the Lifespan and Prostate Cancer Risk

Johanna E Torfadottir,Laufey Steingrimsdottir,Hrafn Tulinius,Laufey Tryggvadottir,Julie L Kasperzyk,Katja Fall,Tamara B Harris,Lorelei A Mucci,Meir Stampfer,Vilmundur Gudnason,Eirikur Jonsson,Hans-Olov Adami,Unnur A Valdimarsdottir,Thor Aspelund,Orn Olafsson

doi:10.1371/journal.pone.0059799

Abstract

ObjectiveTo examine whether fish and fish oil consumption across the lifespan is associated with a lower risk of prostate cancer.DesignThe study was nested among 2268 men aged 67–96 years in the AGES-Reykjavik cohort study. In 2002 to 2006, dietary habits were assessed, for early life, midlife and later life using a validated food frequency questionnaire. Participants were followed for prostate cancer diagnosis and mortality through 2009 via linkage to nationwide cancer- and mortality registers. Adjusting for potential confounders, we used regression models to estimate odds ratios (ORs) and hazard ratios (HRs) for prostate cancer according to fish and fish oil consumption.ResultsAmong the 2268 men, we ascertained 214 prevalent and 133 incident prostate cancer cases, of which 63 had advanced disease. High fish consumption in early- and midlife was not associated with overall or advanced prostate cancer. High intake of salted or smoked fish was associated with a 2-fold increased risk of advanced prostate cancer both in early life (95% CI: 1.08, 3.62) and in later life (95% CI: 1.04, 5.00). Men consuming fish oil in later life had a lower risk of advanced prostate cancer [HR (95%CI): 0.43 (0.19, 0.95)], no association was found for early life or midlife consumption.ConclusionsSalted or smoked fish may increase risk of advanced prostate cancer, whereas fish oil consumption may be protective against progression of prostate cancer in elderly men. In a setting with very high fish consumption, no association was found between overall fish consumption in early or midlife and prostate cancer risk.

Highlights

The association between fish consumption – and two important components in certain types of fish, namely long chain n23 polyunsaturated fatty acids (PUFAs) and vitamin D – and prostate cancer have been investigated in several epidemiologic studies [1,2,3,4,5]
High intake of salted or smoked fish was associated with a 2-fold increased risk of advanced prostate cancer both in early life and in later life
Men consuming fish oil in later life had a lower risk of advanced prostate cancer [hazard ratios (HRs) (95%confidence intervals (CIs)): 0.43 (0.19, 0.95)], no association was found for early life or midlife consumption

Summary

Introduction

The association between fish consumption – and two important components in certain types of fish, namely long chain n23 polyunsaturated fatty acids (PUFAs) and vitamin D – and prostate cancer have been investigated in several epidemiologic studies [1,2,3,4,5]. Different source of fish may be of importance, differences in cooking methods may offer explanations to the mixed findings; cooking white fish using high-temperature has for example been associated with increased risk of advanced prostate cancer [13]. Long chain n23 PUFAs may affect prostate inflammation and carcinogenesis [2] and several studies have reported inverse associations between blood levels of n-3 PUFAs and risk of prostate cancer [14,15,16]. Fatty fish is a good source of vitamin D and higher prediagnostic plasma 25-hydroxyvitamin D levels have been linked to improved prostate cancer prognosis [17,18]

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