Quality score Study Source Study design Age of study population Years of followup Ascertain of cases Blood omega-3 fatty acid level determination Level of comparison used (NOQAS**) Quality score ++ ) Adjustment variables S (4) C (2) E (3) Harvei 1997 [100 ] Norway Nested case control Ave. 50 yo 19.2 years Cancer registries Serum fatty acids Quartiles 3 2 3 9/11 Age, area of residence
Männist
2003 [101 ] Finland Nested case 50–69 yo 5–10 years Cancer registry and histopathology review Serum fatty acids Quartile 2 2 3 8/11 Age, area of residence (urban/rural), level of education, body mass index, alcohol consumption, and the number of years of smoking Chavarro 2007 [102 ] US Nested case control 40–84 yo 13 years Hospital record and histopathology review Blood level fatty acids Quintile 2 1 3 9/11 Age, smoking status at baseline, and length of followup Crowe 103 ] Netherland Nested case control 53–67 yo 4.2 years National and regional cancer registry Blood phospholipid Quintile 2 2 3 9/11 Age, BMI, smoking, alcohol intake, level of education, marital status, and physical activity Park 2009 [104 ] USA Nested case control 45–75 yo 10 years Tumor registry Erythrocyte membrane fatty acids Quartile and tertile 2 2 3 10/11 Age, area of residence, race/ethnicity, family Brasky 2011 [105 ] US Nested case control 55–84 yo 7 years End-study prostate biopsies Serum fatty acids Quartile 4 2 3 9/11 Age, race, family history of prostate cancer, diabetes, BMI, alcohol, and treatment arm Norrish 1999 [99 ] New Zealand Case control 40–80 yo N/A Histopathology Erythrocyte membrane fatty acids Quartile 3 2 3 9/11 Age, height, total nonsteroidal anti-inflammatory drug use, socioeconomic status, and food frequency questionnaire-estimated intake of total polyunsaturated fat Shannon 2010 [97 ] US Case control 50–86 yo N/A Histopathology Erythrocyte membrane fatty acids Tertile 3 2 3 9/11 Age, BMI, race, and family history of prostate cancer Godley 94 ] US Case control
45 yo N/A Histopathology Erythrocyte membrane fatty acids Quartile 3 2 2 8/11 Age and Race Newcomer 2001 [95 ] US Case control 41–66 yo N/A Histopathology Erythrocyte membrane fatty acids Quartile 3 1 3 8/11 Age Ukoli 2009 [96 ] Nigeria Case control ≥45 N/A Histopathology Serum fatty acids Quartile 3 2 3 9/11 Age, level of education, family history of prostate cancer, and waist-hip ratio Ukoli 2010 [98 ] Nigeria Case control ≥45 N/A Histopathology Serum fatty acids Quartile 3 2 3 9/11 Age, level of education, family history of prostate cancer, and waist-hip ratio
