Table 4.
Summary of observational studies on the association between ARA and risk of prostate cancer
| References | Study | Subjects | Exposure Assessment | Prostate cancer assessment (diagnosis) | Adjustment for potential confounders | Assessment of reporting quality * |
Main findings |
||
|---|---|---|---|---|---|---|---|---|---|
| Intergroup comparison | P or Ptrend | ||||||||
|
Study design: cohort study | |||||||||
|
Exposure assessment: dietary intake | |||||||||
| Leitzmann et al. 2004 [67] |
HPFS, USA, 1986-2000, prospective cohort design (14 years follow-up) |
47,866 health professionals aged 40-65, no prior history of cancer |
Semiquantitative FFQ, 131 items, validated against 2 x 1-week DR |
Self-reported physician diagnosis supplemented by medical record and pathology report |
Age, time period, race, family history of prostate cancer, history of type 2 DM and vasectomy, BMI, height, smoking status, physical activity, total energy intake, % of energy from protein intake, monounsaturated fat intake, saturated fat intake and trans unsaturated fat intake, calcium intake, supplemental vitamin E and lycopene |
21 |
Dietary ARA intake, %energy, quintile |
RR(95% CI) |
Ptrend |
| Q1: <0.028 |
1.00 |
0.44 |
|||||||
| Q2: 0.028-0.035 |
1.06(0.94-1.19) |
||||||||
| Q3: 0.036-0.041 |
1.04(0.92-1.18) |
||||||||
| Q4: 0.042-0.049 |
1.02(0.89-1.16) |
||||||||
| Q5: >0.049 |
1.08(0.94-1.25) |
||||||||
|
Study design: nested case-control study | |||||||||
|
Exposure assessment: dietary intake | |||||||||
| Männistö et al. 2003 [68] |
ATBC study, Finland, 1985-1993, nested case-control design (5-8 years follow-up) |
198 prostate cancer patients, 198 controls (free of prostate cancer) matched by age, trial supplementation group |
Self-administered dietary questionnaire, 276 items, validated against 12 x 2-day DR |
Finnish Cancer Registry and Register of Causes of Death |
Resident area, educational level, BMI, alcohol intake, smoking period |
23 |
Dietary ARA intake, g/day, median |
OR(95%CI) |
Ptrend |
| Q1: 0.04 |
1.00 |
0.23 |
|||||||
| Q2: 0.06 |
0.89(0.52-1.54) |
||||||||
| Q3: 0.07 |
1.10(0.64-1.90) |
||||||||
| Q4: 0.10 |
1.31(0.77-2.21) |
||||||||
| |
|
|
|||||||
| Schuurman et al. 1999 [69] |
NLCS, Netherlands, 1986-1992 (6.3 years follow-up), case-cohort design |
642 primary prostate cancer patients from entire cohort, 1,525 subcohort members (selection criteria not shown) aged 55-69 at baseline, without prevalent cancer other than skin cancer, matching not indicated |
Semiquantitative FFQ, 150 items, validated against 3 x 3-day DR |
All regional cancer registries and Dutch national database of pathology reports |
Age, family history of prostate carcinoma, socioeconomic status, total energy intake, total energy-adjusted fat intake |
23 |
Dietary ARA intake, g/day, quintile, median |
RR(95%CI) |
Ptrend |
| Q1: 0.06 |
1.00 |
0.30 |
|||||||
| Q2: 0.09 |
1.21(0.88-1.66) |
||||||||
| Q3: 0.11 |
1.37(1.00-1.87) |
||||||||
| Q4: 0.13 |
1.11(0.80-1.54) |
||||||||
| Q5: 0.17 |
1.20(0.87-1.66) |
||||||||
|
Exposure assessment: blood ARA level | |||||||||
| Crowe et al. 2008 [70] |
EPIC study, Denmark, Germany, Greece, Italy, Netherlands, Spain, Sweden, UK, 1992-2000, nested case-cohort design |
962 prostate cancer patients, 1,061 controls without prevalent cancer other than NMSC, 1 case matched with 1-2 control(s) by study center, age, time of blood sampling, time between blood sampling and last consumption of food or drink |
Plasma phospholipids, GC analysis, precision indicated |
Regional or national cancer registries or combination of health insurance records, cancer and pathology registries and self-report |
BMI, smoking status, alcohol intake, educational level, marital status, physical activity |
26 |
ARA composition mol%, quintile |
RR(95%CI) |
Ptrend |
| Q1: 4.40–7.93 |
1.00 |
0.419 |
|||||||
| Q2: 7.93–8.89 |
1.28(0.96-1.70) |
||||||||
| Q3: 8.90–9.86 |
1.17(0.88-1.56) |
||||||||
| Q4: 9.86–10.98 |
0.81(0.60-1.10) |
||||||||
| Q5: 10.99–19.14 |
0.91(0.65-1.25) |
||||||||
| |
|
|
|
|
|
|
|
|
|
| Chavarro et al. 2007 [71] |
PHS, USA, 1982-1995, nested case-control design within a randomized, double-blind, placebo-controlled factorial aspirin and beta-carotene trial (13 years follow-up) |
476 prostate cancer patients, 476 controls, male physicians without history of cancer except NMSC, 1 case matched with 1 control by age, smoking status, with consideration for trial intervention |
Whole blood fatty acids, GC analysis blinded to case-control status, precision indicated |
Self-report, combined with review of hospital records and pathology reports |
Age, smoking status, length of follow-up |
22 |
ARA concentration (%,), quintile, median |
OR(95%CI) |
Ptrend |
| Q1: 7.9 |
1.00 |
0.98 |
|||||||
| Q2: 9.3 |
1.22(0.82-1.81) |
||||||||
| Q3: 10.1 |
1.05(0.70-1.57) |
||||||||
| Q4: 10.9 |
0.98(0.66-1.46) |
||||||||
| Q5: 12.3 |
1.09(0.72-1.64) |
||||||||
| |
|
|
|
|
|
|
|
|
|
| Männistö et al. 2003 [68] |
ATBC study, Finland, 1985-1993, nested case-control design (5-8 years follow-up) |
198 prostate cancer patients, 198 controls (free of prostate cancer) matched by age, trial supplementation group |
Serum cholesterol ester fatty acids, GC analysis, precision indicated |
Finnish Cancer Registry and Register of Causes of Death |
Resident area, educational level, BMI, alcohol intake, smoking period |
23 |
ARA composition %, quartile, median |
OR(95%CI) |
Ptrend |
| Q1: 3.96 |
1.00 |
0.34 |
|||||||
| Q2: 4.55 |
1.05(0.60-1.84) |
||||||||
| Q3: 5.09 |
0.94(0.54-1.64) |
||||||||
| Q4: 5.89 |
1.39(0.79-2.44) |
||||||||
| |
|
|
|
|
|
|
|
|
|
| Harvei et al. 1997 [72] |
Janus serum bank, Norway, 1973-1994, nested case-control design |
141 prostate cancer patients, 282 controls (eligibility criteria not shown), 1 case matched with 2 controls by age, date of blood sampling, resident area |
Serum phospholipids, GC analysis, blinded to case-control status, precision not indicated |
Cancer Registry and Statistics Norway |
None |
14 |
ARA concentration mg/l, quartile, upper limit |
OR(95%CI) |
Ptrend |
| Q1: 4.86 |
1.0 |
0.6 |
|||||||
| Q2: 5.68 |
1.1(0.6-1.9) |
||||||||
| Q3: 6.68 |
1.2(0.7-2.1) |
||||||||
| Q4: >6.68 |
0.8(0.4-1.5) |
||||||||
| Gann et al. 1994 [73] |
PHS, USA, 1982-1988, nested case-control design within a randomized, double-blind, placebo-controlled factorial aspirin and beta-carotene trial (6 years follow-up) |
120 prostate cancer patients, 120 controls, male physicians without history of cancer except NMSC, 1 case matched with 1 control by age, smoking status without regard to trial intervention |
Plasma cholesterol ester fatty acids, GC analysis blinded to case-control status, precision indicated |
Self-report, combined with review of medical records |
None |
19 |
ARA composition of plasma cholesterol estel %, quartile |
OR |
Ptrend |
| Q1 |
1.00 |
0.76 |
|||||||
| Q2 |
1.81 |
||||||||
| Q3 |
1.00 |
||||||||
| Q4 |
1.36(vs Q1 95% CI: 0.63-2.90) |
||||||||
|
Study design: case-control study (temporal relationship among exposure and outcome is unclear) | |||||||||
|
Exposure assessment: dietary intake | |||||||||
| Hodge et al. 2004 [74] |
Survey, Australia, 1994-1997, case-control design |
858 prostate cancer patients aged <70, 905 controls matched by age |
Melbourne FFQ, 121 items, validated against 2 x 4-day WFR |
Not shown |
Age at selection, study center, calendar year, family history of prostate cancer, country of birth, socioeconomic status |
18 |
Dietary ARA intake, g/day, quintile |
OR(95%CI) |
Ptrend |
| Q1: <0.028 |
1.0 |
0.6 |
|||||||
| Q2: 0.028-0.036 |
1.2(0.8-1.6) |
||||||||
| Q3: 0.037-0.046 |
1.2(0.8-1.6) |
||||||||
| Q4: 0.047-0.059 |
1.0(0.7-1.3) |
||||||||
| Q5: ≥0.06 |
1.0(0.7-1.4) |
||||||||
|
Exposure assessment: blood ARA level | |||||||||
| Ukori et al. 2010 [75] |
Survey, USA and Nigeria, case-control design |
48 African American and 66 Nigerian prostate cancer patients, 96 African American and 226 Nigerian controls, aged ≥40, without any cancer history other than skin cancer, matching not indicated |
Plasma fatty acids (fasting blood), GC analysis, precision not indicated |
Abnormal DRE and/or abnormal PSA (>4ng/ml) with histological diagnosis |
Age, educational level, family history of prostate cancer, WHR |
14 |
ARA concentration μg/ml, quartile American African: |
OR(95%CI) |
Ptrend |
| Q1 vs Q4 |
American African: |
American African: |
|||||||
| Nigerian: |
0.3(0.08-1.11) |
||||||||
| Q1 vs Q4 |
Nigerian: |
<0.05 |
|||||||
| 0.75(0.32-1.74) |
Nigerian: |
||||||||
| Not significant | |||||||||
| Ukori et al. 2009 [76] |
Survey, Nigeria, case-control design |
66 prostate cancer patients, 226 controls, aged ≥40, matching not indicated (same population as Nigerian participants of Ukori et al. 2010) |
Plasma fatty acids (fasting blood), GC analysis, precision not indicated |
Abnormal DRE and/or abnormal PSA (>4ng/ml) with histological diagnosis |
Age, educational level, family history of prostate cancer, WHR |
11 |
ARA concentration μg/ml, quartile |
OR(95%CI) |
Ptrend |
| Q1 |
1.00 |
0.06 |
|||||||
| Q2 |
2.59(0.85-7.86) |
||||||||
| Q3 |
1.93(0.73-5.14) |
||||||||
| Q4 |
0.75(0.32-1.74) |
||||||||
| |
|
|
|
|
|
|
|
|
|
| Newcomer et al. 2001 [77] |
Survey, USA, case-control design |
67 prostate cancer patients, 156 population-based controls, 1 case matched with about 2 controls by age distribution |
Erythrocyte fatty acids, GC analysis blinded to case-control status, precision indicated |
Not shown |
Age |
23 |
ARA composition weight%, quartile |
OR(95%CI) |
Ptrend |
| Q1: ≤13.25 |
1.0 |
0.88 |
|||||||
| Q2: 13.26-14.12 |
1.6(0.7-3.7) |
||||||||
| Q3: 14.13-14.90 |
1.6(0.7-3.5) |
||||||||
| Q4: ≥14.91 |
0.9(0.4-2.3) |
||||||||
| |
|
|
|
|
|
|
|
|
|
| Yang et al. 1999 [78] |
Survey, Korea |
19 prostate cancer patients, 24 benign prostatic hyperplasia patients, 21 normal controls, matched by age, demographics |
Serum fatty acids, GC-MS analysis, precision not indicated |
Not shown |
None |
4 |
ARA composition%, mean (SD) |
ARA composition%, mean(SD) |
P |
| Cancer: |
Normal control: |
Not significant |
|||||||
| 0.77(0.31) |
1.15(0.45) |
||||||||
| Benign: | |||||||||
| 0.95(0.16) | |||||||||
|
Study design: cross-sectional study | |||||||||
|
Exposure assessment: blood ARA level | |||||||||
| Faas et al. 2003 [79] |
Survey, USA, 1995-1998 |
Prostate cancer patients, benign prostate disease patients |
Erythrocyte and plasma phospholipids, GC analysis, precision not indicated |
Pathology reports |
None |
10 |
Erythrocyte ARA composition%, mean(SEM) |
Erythrocyte ARA composition%, mean(SEM) |
P |
| Malignant: |
Benign: |
Erythrocyte: |
|||||||
| 16.33(0.28) |
16.68(0.25) |
Not significant |
|||||||
| Plasma ARA composition%, mean(SEM) |
Plasma ARA composition%, mean(SEM) |
Plasma: |
|||||||
| Malignant: |
Benign: |
Not significant |
|||||||
| 12.60(0.27) |
13.03(0.29) |
||||||||
| Hietanen et al. 1994 [46] |
Survey, UK, cross-sectional design |
10 prostate cancer patients aged 64-85, controls, matched by age, sex, smoking status |
Erythrocyte phospholipids (fasting blood), GC analysis, precision not indicated |
Not shown |
None |
8 |
ARA composition%, mean(SD) |
ARA composition%, mean(SD) |
P |
| Case: |
Control: |
Not significant |
|||||||
| 17.8(1.3) |
18.6(1.3) |
||||||||
| |
|
|
|
|
|
|
|
|
|
| Chaudry et al. 1991 [80] |
Survey, UK |
20 patients admitted for prostatic surgery (10 malignant, 10 benign) |
Plasma phospholipids (fasting blood), GC analysis, precision not indicated |
Histological diagnosis |
None |
6 |
ARA composition%, median(IQR) |
ARA composition%, median(IQR) |
P |
| Malignant: |
Benign: |
Not significant |
|||||||
| 8.93(1.84) |
8.78(2.03) |
||||||||
|
Exposure assessment: tissue ARA level | |||||||||
| Faas et al. 2003 [79] |
Survey, USA, 1995-1998 |
Prostate cancer patients, benign prostate disease patients |
Prostate tissue phospholipids, GC analysis, precision not indicated |
Pathology reports |
None |
10 |
ARA composition%, mean(SEM) |
ARA composition%, mean(SEM) |
P |
| Malignant: |
Benign: |
<0.001 |
|||||||
| 15.20(0.33) |
16.99(0.29) |
||||||||
| |
|
|
|
|
|
|
|
|
|
| Mamalakis et al. 2002 [81] |
Survey, Greece, 1997-1999 |
36 prostate cancer patients, 35 benign prostate hyperplasia patients |
Gluteal adipose tissue and prostate tissue fatty acids, GC analysis, precision not indicated |
DRE, serum PSA, transrectal ultrasound, prostate biopsy |
None |
12 |
Gluteal adipose tissue ARA composition%, mean(SD) |
Gluteal adipose tissue ARA composition%, mean(SD) |
P |
| Malignant: |
Benign: |
Gluteal adipose tissue: |
|||||||
| 0.28(0.12) |
0.25(0.14) |
Not significant |
|||||||
| Prostate tissue ARA composition%, mean(SD) |
Prostate tissue ARA composition%, mean(SD) |
|
|||||||
| Malignant: |
Benign: |
Prostate tissue: |
|||||||
| 5.99(3.65) |
10.71(2.69) |
<0.001 |
|||||||
| Chaudry et al. 1991 [80] | Survey, UK | 20 patients admitted for prostatic surgery (10 malignant, 10 benign) | Prostate tissue phospholipids, GC analysis, precision not indicated | Histological diagnosis | None | 6 | ARA composition%, median(IQR) |
ARA composition%, median(IQR) |
P |
| Malignant: |
Benign: |
|
|||||||
| 11.33(4.12) | 15.55(2.54) | 0.002 | |||||||
ARA Arachidonic acid, ATBC Study: Alpha-tocopherol. Beta-carotene cancer prevention study, BMI Body mass index, DM Diabetes mellitus, DR Diet record, DRE Digital rectal examination, EPIC European prospective investigation into cancer and nutrition, FFQ Food frequency questionnaire, GC Gas chromatography, HPFS Health professionals follow-up study, IQR Interquartile range, NLCS Netherlands cohort study on diet and cancer, NMSC Non-melanoma skin cancer, OR Odds ratio, PHS Physician's health study, PSA Serum level of prostate specific antigen, RR Relative risk, UK United Kingdom, USA United States of America, USDA United states Department of Agriculture, WFR Weighed food record, WHR Waist-to-hip ratio.
*Result of the critical evaluation carried out using the STROBE tool.