Vegetables and breast cancer.

Total breast cancer risk: Data about total vegetables in relation to total breast cancer risk was provided by a pooled analysis of 8 cohorts, and 8 additional cohorts, including a total of 18,023 cases.
A weak significantly increased risk was found in one cohort of very large size, including 5,815 cases (George SM [38]). No other (non)significant associations were found. The average RR = 1.00 (excluding incomplete data from Hirvonen T [29], Iwasaki M [20], Jarvinen R [11]).

Inclusion of intermediate levels of consumption:
(Non)significant effects at any level of consumption were as follows:

  • Zhang S (4) Significant protective at 154-223, and ≥ 385 g/day among premenopausal women.
  • van Gils CH (21) Significant protective at > 109-≤ 160 g/day.
  • Sonestedt E (24) Significant protective at 218 g/day.
  • George SM (38) Though the trend increased significantly, the risk increased nonsignificantly at ≥ 440 g/day.

RRs for the association between total vegetables and breast cancer risk (g/day):


Disease progression: Data about total vegetables in relation to disease progression was provided by 2 cohorts, including a total of 626 cases.
A nonsignificant protective effect against breast cancer recurrence among postmenopausal women was found in the smallest cohort (Hebert JR [12]), but no association was found in the larger cohort (Pierce JP [35]). The average RR = 0.88

Breast cancer mortality: Results were included about a) breast cancer mortality, and b) all-cause mortality following diagnosis of breast cancer. If data about both total mortality, and breast cancer-specific mortality were available following diagnosis of breast cancer, total mortality was chosen as end point.
Data about total vegetables in relation to breast cancer death was provided by 9 cohorts, including a total of 1,144 + X cases (no amount of cases was defined for one cohort (Ewertz M [3]).
A significant protective effect was found in one cohort (McEligot AJ [31]), and nonsignificant effects were found in 3 other cohorts (Ewertz M [3], Holmes D [4], Hebert JR [12]), including a total of 547 + X cases for all 4 cohorts combined (> 48% of all cases). No other (non)significant associations were found. The average RR = 0.90 (excluding incomplete data from Goodwin PC [23], Ingram D [6], Ewertz M [3]).

Inclusion of intermediate levels of consumption:
Significant protective effects at any level of consumption were restricted to one cohort, including 96 cases at the level of consumption of ≥ 154 g/day (31; McEligot AJ). No other (non)significant associations were found.



RRs for the association between total vegetables and breast cancer mortality (g/day):


Conclusion: A significantly increased risk was found in one cohort, but no associations with breast cancer risk were found in the remaining cohorts. Furthermore, no significant associations were found with breast cancer recurrence. No evidence was found for an association between total vegetables and either breast cancer risk or breast cancer recurrence.
Protective associations against mortality were found in 4 cohorts, but these were mostly nonsignificant. The cohorts included 48% of all cases. Suggestive evidence was found for a protective effect of total vegetables against breast cancer mortality (- 10%). No level of consumption could be defined for this effect.

Prospective studies of total vegetables and breast cancer risk:
AuthorCohort nameCasesRelative Risk (RR)
38) George SM (2008)The NIH-AARP Diet and Health Study5,815RR = 1.08 (1.00-1.18; P = 0.009)
29) Hirvonen T (2006)The SU.VI.MAX Study95No significant association (P = 0.98)
24) Sonestedt E (2008)The Malmö Diet and Cancer Cohort544HR = 0.84 (0.64-1.11; P = 0.18)
22) Maynard M (2003)The Boyd Orr cohort82OR = 1.43 (0.70-2.92; P = 0.59)
21) van Gils CH (2005)The EPIC Study3,659RR = 0.98 (0.84-1.14)
20) Iwasaki M (2008)The JPHC Study144No significant association (P = 0.20)
15) Smith-Warner SA (2001)Pooled analysis of 8 cohort studies7,377RR = 0.96 (0.89-1.04; P = 0.54)
11) Jarvinen R (1997)The Finnish Mobile Clinic Health Study88No significant association (no data shown)
1) Shibata A (1992)The Leisure World Study219RR = 0.96 (0.69-1.34)
Total number of cases: 18,023Average RR = 1.00


Prospective studies of total vegetables and breast cancer disease progression:
AuthorCohort nameCasesEnd pointRelative Risk (RR)Dietary assessment following cancer diagnosis
35) Pierce JP (2007)The WHEL Trial517Breast cancer eventsHR = 0.97 (0.67-1.40)yes
12) Hebert JR (1998)No cohort name defined109Breast cancer recurrenceRR = 0.46 (P = 0.08) among postmenopausal womenYes
Total number of cases: 626Average RR = 0.88


Prospective studies of total vegetables and total/breast cancer mortality:
AuthorCohort nameCasesRelative Risk (RR)Dietary assessment following cancer diagnosis
35) Pierce JP (2007)The WHEL Trial314HR = 1.19 (0.74-1.90)Yes
32) Fink BN (2006)The Long Island Breast Cancer Study ProjectPremenopausal: 43.

Postmenopausal: 131.
Premenopausal: HR = 1.40 (0.71-2.76; P = 0.53).

Postmenopausal: HR = 0.92 (0.57-1.48; P = 0.52)
Yes
31) McEligot AJ (2006)No cohort name defined96HR = 0.57 (0.35-0.94; P = 0.02)Yes
23) Goodwin PJ (2003)No cohort name defined52No significant effect (no data shown)Yes
22) Maynard M (2003)The Boyd Orr Cohort36OR = 0.86 (0.30-2.47; P = 0.35)No
12) Hebert JR (1998)No cohort name defined73RR = 0.31 (P = 0.08) among postmenopausal womenYes
6) Ingram D (1994)No cohort name defined21No significant associaton (P = 0.94)Yes
4) Holmes D (1999)The Nurses' Health Study378RR = 0.81 (0.59-1.11; P = 0.07)Yes
3) Ewertz M (1991)No cohort name definedNot definedA nonsignificant slightly decreased risk (no data shown)Yes
Total number of cases: 1,144 + XAverage RR = 0.90