an epic undertaking lessons for vegetarians and vegans from the epic-oxford study paul appleby...
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An EPIC undertaking
Lessons for vegetarians and vegansfrom the EPIC-Oxford study
Paul Appleby
September 2008
The European Prospective Investigation into Cancer and Nutrition (EPIC)
• Largest ever ‘cohort’ study of diet and health• 520,000 participants in 10 European countries• Coordinated at the International Agency for Cancer Research (IARC, part of WHO)• Investigating the relationships between diet, lifestyle and environmental factors and the incidence of cancer and other chronic diseases
EPIC: 520,000 men and women in 10 countries
IARC LYON
PARIS
FLORENCE
MILAN
RAGUSA
TURIN
NAPLESBARCELONA
OVIEDO
GRANADA
MURCIA
PAMPLONA
SAN SEBASTIAN
CAMBRIDGE
OXFORD BILTHOVEN
UTRECHT
ATHENS
HEIDELBERG
POTSDAM
MALMÖ
UMEÅ
AARHUS
COPENHAGEN
TROMSØTromsø
UmeåMalmö
AarhusCopenhagen
OxfordCambridge
PotsdamHeidelberg
UtrechtBilthoven
Paris (nationwide)
TurinMilanFlorenceNaplesRagusa
OviedoSan SebastianPamplonaMurciaGranada
Athens (nationwide)
EPIC-Oxford
• Recruitment 1993-1999 throughout the UK• Aim to recruit as many vegetarians as possible: through GPs for the ‘general public’, by post for vegetarians• Participants:
65,500 diet group, basic characteristics57,500 lifestyle and food frequency questionnaire (FFQ)31,000 first 7-day food diary (1993-99)19,200 blood sample (1993-98)38,000 first follow-up questionnaire (2000-03)31,600 second follow-up questionnaire (2007-08)14,000 second 7-day food diary (2007-08)
Diet groups
For many analyses EPIC-Oxford participants have been divided into one of 4 diet groups.
Group Men Women TotalMeat eaters 7,800 26,100 33,900 (52%)Fish eaters 1,700 8,400 10,100 (15%)Vegetarians 4,200 14,700 18,900 (29%)Vegans 900 1,700 2,600 ( 4%)Total 14,600 50,900 65,500
(Numbers rounded to the nearest 100)
Main findings from EPIC-Oxford to date
• lifestyle characteristics and nutrient intakes• diet and body mass index / weight gain• hypertension and blood pressure• hormones and diet• diet and fracture risk• diet and cancer incidence• diet and mortality• miscellaneous
Selected lifestyle characteristics
WomenCharacteristic Meat Fish Veg VeganMedian age 48 39 35 32Current smoker (%) 11 8 8 10University degree (%) 35 47 44 45Married (%) 71 63 61 51
MenCharacteristic Meat Fish Veg VeganMedian age 51 42 39 35Current smoker (%) 10 10 9 8University degree (%) 50 61 55 49Married (%) 77 69 66 50
Fruit, daily consumption by sex and diet group
0100200300400500600
men women
g/da
y
meat
fish
veget
vegan
Vegetables (excl legumes & potatoes), daily consumption by sex and diet group
0
100
200
300
400
men women
g/da
y
meat
fish
veget
vegan
Mean daily nutrient intakes for women
Nutrient Meat Fish Veg Vgn DRVEnergy (MJ) 8.02 7.75 7.60 6.97 8.10Carbohydrate (% E) 48.3 51.2 52.9 56.1 47Protein (% E) 17.3 14.9 13.8 13.5 14.7Total fat (% E) 31.5 30.7 30.4 27.8 33Saturated fat (% E) 10.4 9.3 9.3 5.1 10PUFA (% E) 5.2 5.4 5.3 7.2 6Dietary fibre (g NSP) 18.9 21.6 21.8 26.4 18Folate (µg) 321 346 350 412 200Vitamin B12 (µg) 7.0 4.9 2.5 0.5 1.5Calcium (mg) 989 1021 1012 582 700Iron (mg) 12.6 12.8 12.6 14.1 14.8
Mean daily nutrient intakes for men
Nutrient Meat Fish Veg Vgn DRVEnergy (MJ) 9.18 8.90 8.78 8.01 10.6Carbohydrate (% E) 46.9 49.8 51.2 54.9 47Protein (% E) 16.0 13.9 13.1 12.9 14.7Total fat (% E) 31.9 31.1 31.1 28.2 33Saturated fat (% E) 10.7 9.4 9.4 5.0 10PUFA (% E) 5.2 5.6 5.7 7.5 6Dietary fibre (g NSP) 18.7 22.1 22.7 27.7 18Folate (µg) 329 358 367 431 200Vitamin B12 (µg) 7.3 5.0 2.6 0.4 1.5Calcium (mg) 1057 1081 1087 610 700Iron (mg) 13.4 14.0 13.9 15.3 8.7
Body Mass Index by diet-group and 10 year age-group among 65,000 men and women in EPIC-Oxford
19
20
21
22
23
24
25
26
27
20- 30- 40- 50- 60- 70- 80- 20- 30- 40- 50- 60- 70- 80-
Age (years)
BM
I kg/
m2 meat
fish
veget
vegan
Davey et al, Public Health Nutrition 2003; 6: 259-268
Men Women
Mean annual weight gain (grams) during 5 years of follow-up by diet group
Diet group Men WomenMeat eater 406 423Fish eater 377 338***Vegetarian 386 392Vegan 284* 303*‘Reverted’1 468 433‘Converted’2242*** 301***
Means are adjusted for age at recruitment, smoking, physical activity, marital status, current paid job, age left school, and age at menarche in women.* / *** denotes significantly lower mean weight gain compared with meat eaters at the P<0.05 / P<0.001 significance level.1 denotes subjects who changed their diet to include more animal foods during follow-up.2 denotes subjects who changed their diet to include fewer animal foods during follow-up.
Prevalence of self-reported hypertension by diet group
Women (% with self-reported hypertension)Adjusted for Meat Fish Veg Vegan PAge alone 12.1 9.6 8.9 7.7 <0.001Age & BMI 10.6 9.7 8.7 8.3 0.07
Men (% with self-reported hypertension)Adjusted for Meat Fish Veg Vegan PAge alone 15.0 9.8 9.8 5.8 <0.001Age & BMI 12.9 9.3 9.5 6.1 0.01
Mean systolic blood pressure by diet group
WomenAdjusted for Meat Fish Veg Vegan PAge alone 120.1 119.0 120.0 117.6 <0.005
Age & BMI 119.7 119.4 120.2 118.4 0.08
‘everything’* 119.4 119.4 120.3 119.5 0.21
MenAdjusted for Meat Fish Veg Vegan PAge alone 126.6 125.3 125.5 122.4 <0.005
Age & BMI 126.0 125.4 125.8 123.5 0.18
‘everything’* 125.0 125.7 126.2 125.2 0.66
* - age, BMI, non-dietary factors, nutrient intakes
Sex hormones and IGF in men
750 subjects in EPIC-Oxford: Allen et al 2000
Testosterone SHBG Free testo. (x 10) IGF-I0
10
20
30
40
50
60Serum concentration, nmol/l
Meat
Vegetarian
Vegan
P=0.003
P=0.001
P=0.14
P=0.002
Self-reported fracture risk by diet group in EPIC-Oxford
Diet group IRR (95% CI)1 IRR (95% CI)2
Meat eaters 1.00 (reference) 1.00 (reference)Fish eaters 1.01 (0.88-1.17) 1.05 (0.90-1.21)Vegetarians 1.00 (0.89-1.13) 1.02 (0.90-1.15)Vegans 1.30 (1.02-1.66) 1.00 (0.69-1.44)
1 Fracture incidence rate ratio compared with meat eaters among all participants, adjusted for age, sex and various non-dietary factors2 As above, but restricted to participants consuming at least 525 mg/day calcium
Cancer in vegetarians: incidence rate ratios for vegetarians compared to non-vegetarians
Cancer Collaborative analysis of mortality, 1999
Latest results for cancer incidence, EPIC-Oxford
Deaths DRR Cancers IRR
Colorectal 278 0.99 (0.77-1.27) 228 1.46 (1.07-2.00)
Lung 203 0.84 (0.59-1.18) 88 1.24 (0.70-2.19)
Breast 210 0.95 (0.55-1.63) 728 0.94 (0.78-1.14)
Prostate 137 0.91 (0.60-1.39) 180 0.85 (0.57-1.27)
All cancers - - 2167 0.92 (0.82-1.02)
All results adjusted for age, sex, smoking and study, as applicable: Key at al Am J Clin Nutr 1999, and unpublished 2008.
EPIC-Oxford: standardized mortality ratios as percentages, compared to UK national rates, among all participants aged below 90 with known diet group
Cause of death
Deaths Non-vegetarians
Vegetarians All participants
All circulatory
931 39 (37-42) 41 (36-47) 40 (37-42)
IHD 464 36 (33-40) 34 (27-41) 36 (33-39)
Stroke 258 44 (38-51) 54 (41-68) 46 (41-52)
All causes 2889 47 (45-49) 48 (45-52) 48 (46-49)
Mortality in EPIC-Oxford: deaths before age 90 among participants with no prior IHD, stroke or cancer
Cause of death Deaths Death rate ratio for vegetarians versus non-vegetarians (95% CI)*
IHD 207 0.89 (0.63-1.34)
Stroke 155 1.17 (0.82-1.67)
Total circulatory 467 1.04 (0.84-1.30)
All causes of death 1458 1.08 (0.95-1.22)
*Adjusted for age, sex and smoking
Miscellaneous findings
• higher frequency of bowel movements among vegetarians and vegans
• compared with people who become vegetarian when adult, life-long vegetarians do not differ in adult height, weight, BMI or age at menarche in women
Selected Publications
• Allen NE, Appleby PN, Davey GK, Key TJ. Hormones and diet: low insulin-like growth factor-I but normal bioavailable androgens in vegan men. British Journal of Cancer 2000; 83: 95-97.• Appleby PN, Davey GK, Key TJ. Hypertension and blood pressure among meat eaters, fish eaters, vegetarians and vegans in EPIC-Oxford. Public Health Nutrition 2002; 5: 645-654.• Davey GK, Spencer EA, Appleby PN, Allen NE, Knox KH, Key TJ. EPIC-Oxford: lifestyle characteristics and nutrient intakes in a cohort of 33883 meat-eaters and 31546 non meat-eaters in the UK. Public Health Nutrition 2003; 6: 259-268.• Spencer EA, Appleby PN, Davey GK, Key TJ. Diet and body mass index in 38000 EPIC-Oxford meat-eaters, fish-eaters, vegetarians and vegans. International Journal of Obesity 2003; 27: 728-734.• Key TJ, Appleby PN, Davey GK, Allen NE, Spencer EA, Travis RC. Mortality in British vegetarians: review and preliminary results from EPIC-Oxford. American Journal of Clinical Nutrition 2003; 78: 533S-538S.• Appleby P, Roddam A, Allen E, Key T. Comparative fracture risk in vegetarians and non-vegetarians in EPIC-Oxford. European Journal of Clinical Nutrition 2007; 61:1400-1406.
Further information and acknowledgements
EPIC-Oxford website: www.epic-oxford.org
Thanks are owing to all participants in EPIC-Oxford, and to Professor Tim Key and colleagues past and present at the Cancer Epidemiology Unit, Oxford University.
EPIC-Oxford is supported by Cancer Research UK, the Medical Research Council, and the European Community.