Relationship of Dietary Intake of Omega-3 and Omega-6 Fatty Acids with Risk of Prostate Cancer Development: A Meta-Analysis of Prospective Studies and Review of Literature

Table 1

Detailed summary of included prospective cohort studies and each study quality scoring.

								Quality scores
								NOQAS			Critical appraisal —UK (11)
								(S)election
Study author (year)	Population of study	Years of followup	Ascertain of cases (prostate cancer)	Omega fatty acid intake determination	Fatty acid omega-3/omega-6	Comparison of group used	Adjustment variables	(C)omparison
								(O)utcome
								S; (4)	C; (2)	O; (3)
Schuurman et al. [9], 1999	58, 279 men; 55–69 yo	6.3 years	Pathology reports	150-item semiquantitative food frequency questionnaire (FFQ)	Omega 3 (ALA, EPA, DHA) and Omega 6 (LA, AA)	Quintile	Age, family history of prostate carcinoma, socioeconomic status, total energy intake	4	2	3	8
Laaksonen et al. [10], 2004	2,002; men; 42–60 yo	12.6 years	Cancer registries	4-day food records nutrition estimated for fatty acids	Omega 6; (LA)	Tertile	Age, dietary intake of energy-adjusted saturated fat, fiber and calcium intake; plasma lipid-standardized tocopherol levels.; BMI, fasting serum insulin and blood glucose levels and nonesterified fatty acid; concentrations	4	2	3	9
Leitzmann; et al. [11],; 2004	44,856 men; 40–75 yo	14 years	Self-report and medical/pathology record	Every 4 years 131-FFQ	Omega 3 and Omega 6 and ALA	Quintile	Age, major ancestry, family history of prostate cancer, BMI at age 21 y, height, type 2 diabetes,; history of vasectomy, cigarette smoking, physical activity, intake of total energy, intakes of calcium, supplemental vitamin E, and lycopene.	3	2	3	8
Koralek; et al. [12],; 2006	29,592 men; 55–74 yo	5.1 years (average years)	Self-report with medical record	Two 24 hr continuing Surveies of Food Intake by Individual over a year using 137 semiquantitative FFQ (ALA composite per food item)	Omega 3 (ALA)	Quintile	Age, current body mass; index, family history of prostate; cancer, history of diabetes,; smoking history, intake of total; energy, lycopene, supplemental; vitamin E, aspirin use, physical; activity, and race	4	2	3	8
Giovannucci; et al. [13], 2007	51,529; 40–75 yo	16 years	Self-report and hospital record	Every 4 years, 131 item semiquantitative FFQ	Omega 3 (ALA)	Quintile	Age, BMI at age 21 years, height, smoking, physical; activity level, family history of prostate cancer, history of diabetes mellitus, race, and intakes of total calories, processed meat, fish, tomato sauce, and vitamin E supplements	3	2	3	8
Neuhouser; et al. [14], 2007	18,314 smoker; 50–62	10 years	Cancer registries	Every 2 years, self-assessment diet FFQ	Omega 6	Quartile	Age, race/ethnicity, energy intake, BMI, smoking and family history	3	2	3	8
Park; et al. [15], 2007	82,483 men; >45 yo	8 years	Cancer registries	Self-administered quantitative FFQ, 180 item 3-day record	Omega 3 (DHA and EPA); ALA; Omega 6	Quintile	Age, ethnicity, family history of prostate cancer, education, BMI, smoking status, and energy intake	4	2	3	10
Wallström; et al. [16], 2007	10,564 men; 45–73 yo	11 years	Cancer registry	Modified diet history seven-day menu book/168 item questionnaire,; 45 min interview	Omega 3 and Omega 6	Quintile	Age, diabetes, waist circumference, height, educational level, alcohol habits, BMI, smoking history, birth country, total calcium intake, consumption of fruits,; vegetables, and red meat; All dietary variables were energy adjusted	4	2	3	10
Chavarro; et al. [17], 2008	20,167 men; 40–84 yo	19 years (mean year)	Medical record	12 months abbreviated food (fish) frequency questionnaire	Omega 3 (long-chain 𝑛-3)	Quintile	Age, BMI, physical activity, intakes of alcohol, tomato products, dairy products, and meat, smoking, race, use of multivitamins, use of vitamin E supplements	3	2	3	8