Dietary fiber, whole grains, carbohydrate, glycemic index, and glycemic load in relation to risk of prostate cancer

Figures & data

Figure 1 Flow diagram of identification of relevant studies.

Table 1 Main characteristics of the studies included in this meta-analysis

Study	Year	Country	Cases	Controls or cohort	Age (years)	Quality score	Type of exposure	Matched or adjusted variables
Sawada et al^Citation13	2015	Japan	825	43,435	45–74	8	Fiber	Age, public health center area, smoking status, drinking frequency, marital status, BMI, and intake of green tea, genistein, SFAs, and carbohydrate
Vidal et al^Citation12	2015	USA	156	274	63 (SD 6.0)	6	Fiber, carbohydrate, GI	Age, race, family history, caloric intake, carbohydrate/fiber intake, BMI, diabetes, physical activity, alcohol, and smoking status
Deschasaux et al^Citation5	2014	France	139	3,313	63	8	Fiber	Age, energy intake without alcohol, intervention group, number of 24-h dietary records, smoking, educational level, physical activity, height, BMI, alcohol intake, family history, PSA calcium intake, processed meat intake, tomato product intake, vitamin E intake, and blood selenium
Hu et al^Citation7	2013	Canada	1,799	5,039	67	7	GI, GL	10-year age group, province, education, BMI, alcohol consumption, pack-year smoking, and energy intake (noncarbohydrate and alcohol)
Drake et al^Citation14	2012	Sweden	817	8,128	45–73	7	Fiber, carbohydrate, whole grains	Age, year of study entry, season of data collection, energy intake, height, waist, physical activity, smoking, educational level, birth in Sweden, alcohol, calcium, and selenium
Egeberg et al^Citation18	2011	Denmark	1,081	26,691	50–64	7	Whole grains	Height, weight, school education, intake of red meat, processed meat and dairy products, and smoking status
Hardin et al^Citation17	2011	USA	470	512	65.8 (SD 8.3)	6	Whole grains	Age, race, institution, energy intake, and history of first-degree relative with prostate cancer
Nimptsch et al^Citation16	2011	USA	5,112	49,934	40–75	7	Fiber, whole grains, GI, GL	Age, BMI, height, history of diabetes, family history, race/ethnicity, smoking, vigorous physical activity, energy intake, alcohol intake, calcium intake, alpha-linolenic acid, and tomato sauce
Shikany et al^Citation15	2011	USA	2,436	30,482	55–74	8	Carbohydrate, GI, GL	Age, year of entry, race, center, compliant for baseline screen, marital status, BMI, vigorous physical activity, smoking, history of diabetes, history of cancer, aspirin use, family history, any prostate problems, prior PSA test, prostate biopsy prior to entry, and dietary factors
Hu et al^Citation19	2010	Canada	1,797	2,547	20–76	7	Carbohydrate	Age, province, education, family income, BMI, total alcohol intake, and total energy intake
Lewis et al^Citation4	2009	USA	478	382	63.3 (SD 8.2) 66.9 (SD 8.1)	6	Fiber, carbohydrate, whole grains	Age, education, BMI, smoking history, family history of prostate cancer in first-degree relatives, and total caloric intake
Suzuki et al^Citation20	2009	Multicenter	2,747	142,590	52	8	Fiber	Study center, age, energy intake, height, weight, smoking, education, and marital status
George et al^Citation21	2009	USA	15,949	262,642	50–71	7	GI, GL	Age, race/ethnicity, education, marital status, BMI, family history of any cancer, physical activity, smoking, alcohol consumption, and energy intake
McCann et al^Citation23	2005	USA	433	538	NA	6	Fiber, carbohydrate	Age, county of residence, education, BMI, cigarette smoking status, total energy, and vegetable intake
Walker et al^Citation22	2005	Canada	80	334	65.0 (SD 6.0)	5	Fiber, carbohydrate	Age, alcohol intake, carbohydrate/fiber, total energy, protein, fat, cholesterol, and calcium
Pelucchi et al^Citation24	2004	Italy	1,294	1,451	66 (46–74)	6	Fiber	Age, study center, education, family history, smoking, alcohol consumption, and energy intake
Augustin et al^Citation6	2004	Italy	1,204	1,352	66 (46–74)	6	GI, GL	Age, study center, education, family history, energy intake, alcohol consumption, smoking, BMI, occupational physical activity at 50 years, intake of fiber, and intake of lycopene
Lu et al^Citation25	2001	USA	65	132	59.98	5	Fiber	Age, race, education, alcohol drinking, smoking, family history, and total dietary caloric intake
Ramon et al^Citation26	2000	Spain	217	434	≤80	6	Fiber, carbohydrate	Age, residence, calories, family history, and BMI; carbohydrate further adjusted for total protein and total fat intake
Chan et al^Citation27	2000	Finland	184	27,062	50–69	7	Carbohydrate	Supplementation group, education, age, BMI, energy, and number of years as a smoker
Deneo-Pellegrini et al^Citation29	1999	Uruguay	175	233	40–89	6	Fiber, carbohydrate, whole grains	Age, residence, urban/rural status, education, family history, BMI, and total energy intake
Jain et al^Citation28	1999	Canada	617	636	69.8	7	Whole grains	Total energy, vasectomy, age, ever-smoked, marital status, study area, BMI, education, ever-used multivitamin supplements, area of study, and log-converted amounts for grains, fruit, vegetables, total plants, total carotenoids, folic acid, dietary fiber, conjugated linoleic acid, vitamin E, vitamin C, retinol, total fat, and linoleic acid
Chatenoud et al^Citation30	1998	Italy	127	7,990	<75	6	Whole grains	Age, sex, education, smoking, alcohol, and BMI
Andersson et al^Citation31	1996	Sweden	526	536	70.7 (SD 5.9)	6	Fiber, carbohydrate	Age and energy
Walker et al^Citation3	1992	South Africa	166	166	69.2 (SD 8.9)	5	Fiber	Age and residence
West et al^Citation32	1991	USA	358	679	45–74	6	Carbohydrate	Since interaction and confounding did not exist, crude ORs are presented
Oishi et al^Citation33	1988	Japan	100	100	50–79	5	Fiber, carbohydrate	Age, date of admission

Abbreviations: BMI, body mass index; SD, standard deviation; GI, glycemic index; h, hours; PSA, prostate specific antigen; GL, glycemic load; ORs, odds ratios; SFAs, saturated fatty acids; NA, not available.

Figure 2 Summary RR of fiber intake and prostate cancer risk.

Note: Weights are from random effects analysis.
Abbreviations: RR, relative risk; CI, confidence interval.

Figure 3 Summary RR of whole grains intake and prostate cancer risk.

Note: Weights are from random effects analysis.
Abbreviations: RR, relative risk; CI, confidence interval.

Figure 4 Summary RR of carbohydrate intake and prostate cancer risk.

Note: Weights are from random effects analysis.
Abbreviations: RR, relative risk; CI, confidence interval.

Figure 5 Summary RRs of GI (A), GL (B), and prostate cancer risk.

Note: Weights are from random effects analysis.
Abbreviations: RRs, relative risks; GI, glycemic index; GL, glycemic load; CI, confidence interval.

Table 2 Pooled and subgroup analyses stratified by study design and area

	Fiber intake			Whole grains intake			Carbohydrate intake			GI			GL
	Na	RR (95% CI)	I^2 (%)	Na	RR (95% CI)	I^2 (%)	Na	RR (95% CI)	I^2 (%)	Na	RR (95% CI)	I^2 (%)	Na	RR (95% CI)	I^2 (%)
Overall	16	0.94(0.85–1.05)	39.5	8	1.13 (0.98–1.30)	52.5	13	0.96(0.81–1.14)	51.2	6	1.06(0.96–1.18)	69.5	5	1.04(0.91–1.18)	67.0
Study design
Cohort	5	0.99(0.87–1.14)	52.6	3	1.10(1.02–1.19)	0.0	3	0.98(0.83–1.17)	1.9	3	0.98(0.94–1.02)	0.0	3	0.96(0.87–1.06)	43.9
Case-control	11	0.89(0.75–1.06)	27.6	5	1.27(0.87–1.86)	69.4	10	0.94(0.73–1.20)	60.1	3	1.34(1.10–1.62)	22.1	2	1.36(1.08–1.70)	0.0
Area
Asia	2	0.96(0.76–1.21)	0.0	0	–	–		1.33 (0.76–2.32)	–	0	–	–	0	–	–
Europe	6	0.94(0.79–1.1 1)	48.9	3	1.03 (0.90–1.18)	0.0	4	0.96(0.75–1.22)	44.5		1.57(1.19–2.07)	–		1.41 (1.05–1.90)	–
North America	6	0.95(0.75–1.21)	35.8	4	1.22(0.93–1.61)	72.5	7	1.00(0.78–1.29)	54.5	5	1.00(0.94–1.07)	33.8	4	0.98(0.88–1.10)	53.0

Note:

a The number of studies included.

Abbreviations: GI, glycemic index; GL, glycemic load; RR, relative risk; CI, confidence interval.

Figure 6 Begg’s funnel plots of dietary fiber, whole grains, carbohydrate, GI, GL, and prostate cancer risk.

Abbreviations: GI, glycemic index; GL, glycemic load; RR, relative risk.

Figure 7 Sensitivity analyses of dietary fiber, whole grains, carbohydrate, GI, GL, and prostate cancer risk.

Abbreviations: GI, glycemic index; GL, glycemic load; CI, confidence interval.

SawadaNIwasakiMYamajiTJapan Public Health Center–based Prospective Study GroupFiber intake and risk of subsequent prostate cancer in Japanese menAm J Clin Nutr2015101111812525527755

 PubMed Web of Science ®Google Scholar

VidalACWilliamsCDAllottEHCarbohydrate intake, glycemic index and prostate cancer riskProstate201575443043925417840

 PubMed Web of Science ®Google Scholar

DeschasauxMPouchieuCHisMHercbergSLatino-MartelPTouvierMDietary total and insoluble fiber intakes are inversely associated with prostate cancer riskJ Nutr2014144450451024553693

 PubMed Web of Science ®Google Scholar

HuJLa VecchiaCAugustinLSCanadian Cancer Registries Epidemiology Research GroupGlycemic index, glycemic load and cancer riskAnn Oncol201324124525122831983

 PubMed Web of Science ®Google Scholar

DrakeISonestedtEGullbergBDietary intakes of carbohydrates in relation to prostate cancer risk: a prospective study in the Malmo Diet and Cancer cohortAm J Clin Nutr20129661409141823134882

 PubMed Web of Science ®Google Scholar

EgebergROlsenAChristensenJIntake of whole-grain products and risk of prostate cancer among men in the Danish Diet, Cancer and Health cohort studyCancer Causes Control20112281133113921656162

 PubMed Web of Science ®Google Scholar

HardinJChengIWitteJSImpact of consumption of vegetable, fruit, grain, and high glycemic index foods on aggressive prostate cancer riskNutr Cancer201163686087221774611

 PubMed Web of Science ®Google Scholar

NimptschKKenfieldSJensenMKDietary glycemic index, glycemic load, insulin index, fiber and whole-grain intake in relation to risk of prostate cancerCancer Causes Control2011221516121069447

 PubMed Web of Science ®Google Scholar

ShikanyJMFloodAPKitaharaCMDietary carbohydrate, glycemic index, glycemic load, and risk of prostate cancer in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO) cohortCancer Causes Control2011227995100221553078

 PubMed Web of Science ®Google Scholar

HuJLa VecchiaCGibbonsLNegriEMeryLNutrients and risk of prostate cancerNutr Cancer201062671071820661818

 PubMed Web of Science ®Google Scholar

LewisJESoler-VilaHClarkPEKrestyLAAllenGOHuJJIntake of plant foods and associated nutrients in prostate cancer riskNutr Cancer200961221622419235037

 PubMed Web of Science ®Google Scholar

SuzukiRAllenNEKeyTJA prospective analysis of the association between dietary fiber intake and prostate cancer risk in EPICInt J Cancer2009124124524918814263

 PubMed Web of Science ®Google Scholar

GeorgeSMMayneSTLeitzmannMFDietary glycemic index, glycemic load, and risk of cancer: a prospective cohort studyAm J Epidemiol2009169446247219095757

 PubMed Web of Science ®Google Scholar

McCannSEAmbrosoneCBMoysichKBIntakes of selected nutrients, foods, and phytochemicals and prostate cancer risk in western New YorkNutr Cancer2005531334116351504

 PubMed Web of Science ®Google Scholar

WalkerMAronsonKJKingWDietary patterns and risk of prostate cancer in Ontario, CanadaInt J Cancer2005116459259815825170

 PubMed Web of Science ®Google Scholar

PelucchiCTalaminiRGaleoneCFibre intake and prostate cancer riskInt J Cancer2004109227828014750181

 PubMed Web of Science ®Google Scholar

AugustinLSGaleoneCDal MasoLGlycemic index, glycemic load and risk of prostate cancerInt J Cancer2004112344645015382070

 PubMed Web of Science ®Google Scholar

LuQYHungJCHeberDInverse associations between plasma lycopene and other carotenoids and prostate cancerCancer Epidemiol Biomarkers Prev200110774975611440960

 PubMed Web of Science ®Google Scholar

RamonJMBouRRomeaSDietary fat intake and prostate cancer risk: a case-control study in SpainCancer Causes Control200011867968511065004

 PubMed Web of Science ®Google Scholar

ChanJMPietinenPVirtanenMDiet and prostate cancer risk in a cohort of smokers, with a specific focus on calcium and phosphorus (Finland)Cancer Causes Control200011985986711075876

 PubMed Web of Science ®Google Scholar

Deneo-PellegriniHDe StefaniERoncoAMendilaharsuMFoods, nutrients and prostate cancer: a case-control study in UruguayBr J Cancer1999803–459159710408871

 PubMed Web of Science ®Google Scholar

JainMGHislopGTHoweGRGhadirianPPlant foods, antioxidants, and prostate cancer risk: findings from case-control studies in CanadaNutr Cancer199934217318410578485

 PubMed Web of Science ®Google Scholar

ChatenoudLTavaniALa VecchiaCWhole grain food intake and cancer riskInt J Cancer199877124289639389

 PubMed Web of Science ®Google Scholar

AnderssonSOWolkABergströmREnergy, nutrient intake and prostate cancer risk: a population-based case-control study in SwedenInt J Cancer19966867167228980172

 PubMed Web of Science ®Google Scholar

WalkerARWalkerBFTsotetsiNGSebitsoCSiwediDWalkerAJCase-control study of prostate cancer in black patients in Soweto, South AfricaBr J Cancer19926534384411558801

 PubMed Web of Science ®Google Scholar

WestDWSlatteryMLRobisonLMFrenchTKMahoneyAWAdult dietary intake and prostate cancer risk in Utah: a case-control study with special emphasis on aggressive tumorsCancer Causes Control19912285941873441

 PubMed Web of Science ®Google Scholar

OishiKOkadaKYoshidaOA case-control study of prostatic cancer with reference to dietary habitsProstate19881221791903368406

 PubMed Web of Science ®Google Scholar