Lifestyle factors and small intestine adenocarcinoma risk: A systematic review and meta-analysis.
BACKGROUND
Although the incidence of small intestinal adenocarcinoma (SIA) is low, rates are increasing and little information regarding modifiable lifestyle risk factors is available.


OBJECTIVE
To provide a systematic review of lifestyle factors and SIA risk.


METHODS
Ovid MEDLINE, EMBASE and Web of science were searched from inception to week 1 October 2013. Nine publications that reported on SIA risk in relation to alcohol intake (n=6), tobacco smoking (n=6), diet (n=5), body mass (n=3), physical activity (n=1), hormone use (n=1) and/or socio-economic status (n=3) were retrieved. Results for alcohol, smoking and SIA risk were pooled using random-effects meta-analyses to produce relative risks (RR) and 95% confidence intervals (CI).


RESULTS
The summary RR for individuals consuming the highest versus lowest category of alcohol intake was 1.51 (95% CI 0.83-2.75; n=5 studies) with significant increased risks emerging in sensitivity analysis with reduced heterogeneity (RR: 1.82, 95% CI: 1.05-3.15; n=4 studies). The pooled SIA RR for individuals in the highest versus lowest category of smoking was 1.24 (95% CI 0.71-2.17; n=5 studies). In relation to dietary factors, high fibre intakes and normal body weight may be protective, while high intakes of red/processed meat and sugary drinks may increase SIA risk. Evidence on socio-economic status and SIA risk was equivocal. Data on other factors were too sparse to draw any conclusions.


CONCLUSIONS
Alcohol may be associated with an increased risk of SIA. Further investigation of lifestyle factors, particularly alcohol, smoking and diet, in the aetiology of this cancer is warranted in large consortial studies.
Cancer Epidemiology & Health Services Research Group, Centre for Public Health, Queens University Belfast, United Kingdom.
Caoimhe M
CM
Bennett
Cancer Epidemiology & Health Services Research Group, Centre for Public Health, Queens University Belfast, United Kingdom. Electronic address: h.coleman@qub.ac.uk.
Helen G
HG
Coleman
Cancer Epidemiology & Health Services Research Group, Centre for Public Health, Queens University Belfast, United Kingdom; Public Health Agency, United Kingdom.
Philip G
PG
Veal
Cancer Epidemiology & Health Services Research Group, Centre for Public Health, Queens University Belfast, United Kingdom.
Marie M
MM
Cantwell
Cancer Epidemiology & Health Services Research Group, Centre for Public Health, Queens University Belfast, United Kingdom.
Charlotte C L
CC
Lau
Cancer Epidemiology & Health Services Research Group, Centre for Public Health, Queens University Belfast, United Kingdom.
Liam J
LJ
Murray
D000230:Adenocarcinoma / Q000453:epidemiology*; D000428:Alcohol Drinking / Q000009:adverse effects*; D004032:Diet; D005247:Feeding Behavior; D006801:Humans; D015994:Incidence; D007414:Intestinal Neoplasms / Q000453:epidemiology*; D007421:Intestine, Small; D008019:Life Style; D008460:Meat / Q000009:adverse effects; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects
Alcohol; Cancer; Diet; Risk factors; Small intestine; Smoking