Legumes (pulses) and prostate cancer.

Prostate cancer risk: Data about the relation between legumes and total prostate cancer risk was provided by 4 cohort, including a total of 5,315 cases.
Significant protective effects were found in 3 out of 4 cohorts (Mills PK [1], Schuurman AG [10], Park SY [17]), including 5,179 cases. Questionnaires from 2 cohorts did not include soy (1, 10), and results from the third cohort were similar when soy products were excluded. No association was found in the remaining cohort, which was of very small size (Tseng M [13]). The average RR = 0.86 (excluding incomplete data from Tseng M [13]).

Inclusion of intermediate levels of consumption:
The figure below shows RR from 2 cohorts including a total of 5,010 cases (94% of cases from all cohorts combined). Results from one cohort could not be included since they were presented in frequency of use (1):
Protective effects could be found at the level of consumption of > 62g/day (Schuurman AG), and > 71 g/day (Park SY).

RRs for the association between total legumes and total prostate cancer risk (g/day):

Advanced prostate cancer risk: Data about the relation with advanced stage prostate cancer risk was provided by 2 cohorts.
A significant protective effect against nonlocalized/high grade disease was found in the largest cohort (17), but no association was found with poorly/undifferentiated cancer in the other cohort (10).
Prostate cancer mortality: Data about the relation with prostate cancer mortality was provided by 3 cohorts (5, 20, 22). No associations were found.

Conclusion: Significant protective effects of legumes against total prostate cancer risk were found in 3 cohorts of moderate-large size and including 97% of all cases. No other associations were found. Legumes possibly protect against total prostate cancer risk (- 14%). This effect could be found at the level of consumption of > 71 g/day.
No evidence was found for an association between legumes and advanced prostate cancer risk or mortality. This evidence did not change when advanced cancer and mortality were considered one end point.

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Stratified by tumor stage:

Total prostate cancer

Nonlocalized (regional or distant) or high-grade (gleason score ≥ 7/poorly differentiated) prostate cancer

RR = 0.89 (0.80-0.99; P = 0.007) for the highest vs lowest quintile of consumption.

Amount specific data (g/1,000 kcal):
< 6.4: RR = 1.
6.4-< 10.8: RR = 0.97 (0.88-1.07).
10.8-< 16.5: RR = 1.02 (0.92-1.12).
16.5-< 28.2: RR = 0.94 (0.85-1.04).
≥ 28.2: RR = 0.89 (0.80-0.99).

RR = 0.74 (0.61-0.90; P = 0.007) for the highest vs lowest quintile of consumption.

Amount specific data (g/1,000 kcal):
< 6.4: RR = 1.
6.4-< 10.8: RR = 0.89 (0.74-1.06).
10.8-< 16.5: RR = 0.86 (0.71-1.03).
16.5-< 28.2: RR = 0.84 (0.70-1.01).
≥ 28.2: RR = 0.74 (0.61-0.90).

Total prostate cancer stratified by ethnicity:

African Americans
(1,186 cases)

Japanese Americans
(1,062 cases)

Latinos
(1,040 cases)

Whites
(924 cases)

RR = 0.95 (0.78-1.16; P = 0.39) for the highest vs lowest quintile of consumption.

Amount specific data (median intake in g/1,000 kcal):
3.3: RR = 1.
7.5: RR = 1.05 (0.87-1.27).
11.7: RR = 1.04 (0.86-1.26).
17.1: RR = 0.98 (0.80-1.19).
29.2: RR = 0.95 (0.78-1.16).

RR = 1.00 (0.82-1.21; P = 0.91) for the highest vs lowest quintile of consumption.

Amount specific data (median intake in g/1,000 kcal):
5.6: RR = 1.
9.8: RR = 1.00 (0.82-1.22).
13.9: RR = 0.98 (0.80-1.20).
19.8: RR = 0.87 (0.71-1.07).
35.2: RR = 1.00 (0.82-1.21).

RR = 0.80 (0.65-1.00; P = 0.01) for the highest vs lowest quintile of consumption.

Amount specific data (median intake in g/1,000 kcal):
7.0: RR = 1.
16.1: RR = 1.03 (0.85-1.24).
26.7: RR = 0.92 (0.75-1.12).
43.0: RR = 0.86 (0.70-1.06).
77.7: RR = 0.80 (0.65-1.00).

RR = 0.84 (0.68-1.04; P = 0.15) for the highest vs lowest quintile of consumption.

Amount specific data (median intake in g/1,000 kcal):
2.3: RR = 1.
6.1: RR = 0.99 (0.80-1.21).
10.0: RR = 0.92 (0.75-1.14).
15.1: RR = 1.06 (0.86-1.30).
27.6: RR = 0.84 (0.68-1.04).

Stratified by tumor stage:

Total prostate cancer

Nonlocalized (regional or distant) or high-grade (gleason score ≥ 7/poorly differentiated) prostate cancer

RR = 0.90 (0.81-1.01; P = 0.01) for the highest vs lowest quintile of consumption.

Amount specific data (g/1,000 kcal):
< 3.6: RR = 1.
3.6-< 6.8: RR = 1.01 (0.91-1.12).
6.8-< 11.2: RR = 1.02 (0.92-1.12).
11.2-< 21.3: RR = 1.01 (0.91-1.11).
≥ 21.3: RR = 0.90 (0.81-1.01).

RR = 0.72 (0.59-0.89; P = 0.01) for the highest vs lowest quintile of consumption.

Amount specific data (g/1,000 kcal):
< 3.6: RR = 1.
3.6-< 6.8: RR = 0.87 (0.72-1.05).
6.8-< 11.2: RR = 0.86 (0.72-1.04).
11.2-< 21.3: RR = 0.83 (0.69-1.00).
≥ 21.3: RR = 0.72 (0.59-0.89).

Total prostate cancer stratified by ethnicity:

African Americans
(1,186 cases)

Japanese Americans
(1,062 cases)

Latinos
(1,040 cases)

Whites
(924 cases)

RR = 0.95 (0.78-1.15; P = 0.36) for the highest vs lowest quintile of consumption.

Amount specific data (median intake in g/1,000 kcal):
3.1: RR = 1.
7.2: RR = 1.03 (0.85-1.25).
11.2: RR = 1.01 (0.83-1.22).
16.5: RR = 0.95 (0.78-1.15).
28.1: RR = 0.95 (0.78-1.15).

RR = 0.99 (0.81-1.21; P = 0.62) for the highest vs lowest quintile of consumption.

Amount specific data (median intake in g/1,000 kcal):
1.4: RR = 1.
3.4: RR = 1.12 (0.92-1.35).
5.4: RR = 0.99 (0.81-1.20).
7.7: RR = 1.04 (0.85-1.26).
12.7: RR = 0.99 (0.81-1.21).

RR = 0.80 (0.65-1.00; P = 0.01) for the highest vs lowest quintile of consumption.

Amount specific data (median intake in g/1,000 kcal):
6.6: RR = 1.
15.5: RR = 1.07 (0.89-1.30).
26.1: RR = 0.93 (0.77-1.14).
42.4: RR = 0.90 (0.74-1.11).
77.0: RR = 0.80 (0.65-1.00).

RR = 0.90 (0.73-1.11; P = 0.26) for the highest vs lowest quintile of consumption.

Amount specific data (median intake in g/1,000 kcal):
1.8: RR = 1.
5.1: RR = 1.03 (0.83-1.26).
8.5: RR = 0.94 (0.76-1.17).
12.7: RR = 0.99 (0.80-1.22).
23.0: RR = 0.90 (0.73-1.11).

Prostate cancer risk in subgroups on differentiation grade. RRs are per 25 g/day increment

well differentiated

moderately differentiated

poorly or undifferentiated

RR = 0.93 (0.76-1.15)

RR = 0.88 (0.72-1.08)

RR = 1.07 (0.87-1.32)

**Prospective studies of legumes and prostate cancer mortality:**
Author	Cohort name	Subjects	Years of follow-up	Cases	End point	Consumption of	Relative Risk (RR)	Adjustments
22) Smit E (2007)	The Puerto Rico Heart Health Program.	9,777 men aged 35-79.	1965-2005	167?	Prostate cancer death	Legumes (not defined, but non-soy)	OR = 1.06 (0.48-2.32;P = 0.93) for the highest vs lowest quartile of consumption. Amount specific data in cups/day (servings/day): 0 (None): OR = 1. 0.25-0.5 (0.92-1.84): OR = 1.14 (0.72-1.79). 0.75 (2.76): OR = 0.90 (0.48-1.69). ≥ 1 (3.68): OR = 1.06 (0.48-2.32).	Age, education, BMI, living (urban/rural), physical activity, smoking and residual energy intake.
20) Iso H (2007)	The JACC Study.	41,816 men. (Japan)	Not defined.	154	Prostate cancer mortality	Boiled beans (not defined)	HR = 1.11 (0.71-1.76) for the highest vs lowest tertile of consumption. Amount specific data: < 1/w: HR = 1. 1-2/w: HR = 1.12 (0.73-1.70). ≥ 3/w: HR = 1.11 (0.71-1.76).	Age and study area.
5) Hsing AW. (1990)	The Lutheran Brotherhood Cohort Study.	17,633 white men age ≥ 35. (USA)	20 (1966-1986)	149?	Prostate cancer mortality	Beans	No individual food item was found to increase or decrease risk significantly (no data shown).	age, tobacco

Prospective studies of legumes and prostate cancer mortality:

Author

Cohort name

Subjects

Years of follow-up

Cases

End point

Consumption of

Relative Risk (RR)

Adjustments

22) Smit E (2007)

The Puerto Rico Heart Health Program.

9,777 men aged 35-79.

1965-2005

167?

Prostate cancer death

Legumes (not defined, but non-soy)

OR = 1.06 (0.48-2.32;P = 0.93) for the highest vs lowest quartile of consumption.

Amount specific data in cups/day (servings/day):
0 (None): OR = 1.
0.25-0.5 (0.92-1.84): OR = 1.14 (0.72-1.79).
0.75 (2.76): OR = 0.90 (0.48-1.69).
≥ 1 (3.68): OR = 1.06 (0.48-2.32).

Age, education, BMI, living (urban/rural), physical activity, smoking and residual energy intake.

20) Iso H (2007)

The JACC Study.

41,816 men.
(Japan)

Not defined.

154

Prostate cancer mortality

Boiled beans (not defined)

HR = 1.11 (0.71-1.76) for the highest vs lowest tertile of consumption.

Amount specific data:
< 1/w: HR = 1.
1-2/w: HR = 1.12 (0.73-1.70).
≥ 3/w: HR = 1.11 (0.71-1.76).

Age and study area.

5) Hsing AW. (1990)

The Lutheran Brotherhood Cohort Study.

17,633 white men age ≥ 35.
(USA)

20
(1966-1986)

149?

Prostate cancer mortality

Beans

No individual food item was found to increase or decrease risk significantly (no data shown).

age, tobacco

Cancer & Diet. A systematic review.

Literature review.

Relating various aspects of our diet
to prostate cancer risk & mortality.

Legumes (pulses) and prostate cancer.

Cancer & Diet. A systematic review.

Literature review.

Relating various aspects of our dietto prostate cancer risk & mortality.

Legumes (pulses) and prostate cancer.

Relating various aspects of our diet
to prostate cancer risk & mortality.