Smoking attenuates the negative association between carotenoids consumption and colorectal cancer risk.
OBJECTIVE
Consumption of vegetables and fruits, physical activity, obesity and caloric intake are all strongly related to the risk of colorectal cancer (CRC). The association between dietary intake of carotenoids from vegetables/fruits and risk of CRC in the context of cigarette smoking was studied in a nutritionally diverse population.


METHODS
The study included 1,817 age sex residence-matched case-control pairs from a population-based study in Northern Israel. Data were acquired by food-frequency questionnaire. Individual intake of carotenoid isomers was calculated using an Israeli food content database. Odds ratios (ORs) were calculated using conditional logistic regression models adjusted for known risk factors.


RESULTS
Strong inverse associations were found with consumption of 9-cis-beta-carotene (OR = 0.35, 0.26-0.47), all-trans-beta-carotene (OR = 0.58, 0.44-0.76), cis-beta-cryptoxanthin (OR = 0.67, 0.50-0.90), all-trans-zeaxanthin (OR = 0.64, 0.48-0.86), and lutein (OR = 0.74, 0.57-0.96). Lycopene (OR = 2.22, 1.71-2.89) and all-trans-beta-cryptoxanthin (OR = 2.01, 1.48-2.73) were associated with increased risk of CRC. Inverse associations of most carotenoids with CRC, demonstrated in non-smokers, were much attenuated or reversed in past or current smokers with a highly significant interaction term.


CONCLUSIONS
Consumption of most dietary carotenoids was found to be strongly associated with reduced risk of CRC. However, smoking significantly attenuated or reversed this observed protective effect on CRC occurrence. Smokers should be advised that smoking also hampers the potential health promoting effects of high fruit and vegetable consumption.
Chaiter
Y
Y
Department of Community Medicine and Epidemiology, CHS National Cancer Control Center, Carmel Medical Center and B. Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, 7 Michal St, 34362, Haifa, Israel.
Gruber
S B
SB
Ben-Amotz
A
A
Almog
R
R
Rennert
H S
HS
Fischler
R
R
Rozen
G
G
Rennert
G
G
D000368:Aged; D002277:Carcinoma / Q000453:epidemiology / Q000209:etiology*; D002338:Carotenoids / Q000008:administration & dosage* / Q000032:analysis; D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000209:etiology*; D004032:Diet; D015930:Diet Records; D004435:Eating / Q000502:physiology; D005260:Female; D005638:Fruit; D006801:Humans; D007557:Israel / Q000453:epidemiology; D008297:Male; D016017:Odds Ratio; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology*; D054928:Validation Studies as Topic; D014675:Vegetables
D002338:Carotenoids