The Joint Effects of Lifestyle Factors and Comorbidities on the Risk of Colorectal Cancer: A Large Chinese Retrospective Case-Control Study
December
The Joint Effects of Lifestyle Factors and Comorbidities on the Risk of Colorectal Cancer: A Large Chinese Retrospective Case- Control Study
Junjie Hang 0 1
Binxin Cai 0 1
Peng Xue 0 1
Lei Wang 0 1
Hai Hu 0 1
Yangyang Zhou 0 1
Shujuan Ren 0 1
Jiajin Wu 0 1
Meiying Zhu 0 1
Donghui Chen 0 1
Haiyan Yang 0 1
Liwei Wang 0 1
0 1 Department of Oncology and Pancreatic Cancer Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China , 2 Shanghai Key Laboratory of Pancreatic Disease , Shanghai , China , 3 Songjiang Center of Shanghai Municipal Center for Disease Control and Prevention , Shanghai , China
1 Editor: Nathan A. Ellis, University of Arizona, UNITED STATES
Background
Methods
Colorectal cancer (CRC) is a major cause of cancer morbidity and mortality. In previous
epidemiologic studies, the respective correlation between lifestyle factors and comorbidity
and CRC has been extensively studied. However, little is known about their joint effects on
CRC.
We conducted a retrospective case-control study of 1,144 diagnosed CRC patients and
60,549 community controls. A structured questionnaire was administered to the participants
about their socio-demographic factors, anthropometric measures, comorbidity history and
lifestyle factors. Logistic regression model was used to calculate the odds ratio (ORs) and
95% confidence intervals (95%CIs) for each factor. According to the results from logistic
regression model, we further developed healthy lifestyle index (HLI) and comorbidity history
index (CHI) to investigate their independent and joint effects on CRC risk.
Results
Four lifestyle factors (including physical activities, sleep, red meat and vegetable
consumption) and four types of comorbidity (including diabetes, hyperlipidemia, history of
inflammatory bowel disease and polyps) were found to be independently associated with the risk of
CRC in multivariant logistic regression model. Intriguingly, their combined pattern- HLI and
CHI demonstrated significant correlation with CRC risk independently (ORHLI: 3.91, 95%CI:
3.13–4.88; ORCHI: 2.49, 95%CI: 2.11–2.93) and jointly (OR: 10.33, 95%CI: 6.59–16.18).
Competing Interests: The authors have declared
that no competing interests exist.
Conclusions
There are synergistic effects of lifestyle factors and comorbidity on the risk of colorectal
cancer in the Chinese population.
Introduction
CRC is a major cause of cancer-related morbidity and mortality. It is the third most commonly
diagnosed cancer among males and the second among females on a global level [
1
]. In China,
an annual report on status of cancer in 2011 showed that the incidence and mortality of CRC
accounted for 9.20% and 7.09% of all kinds of cancers respectively [
2
]. Without effective
prevention strategy, the male and female CRC incidence rate would reach 33.92/100,000 and
27.13/100,000 in urban areas; and 13.61/100,000 and 13.68/100,000 in rural areas by the year
2015 in China [
3
]. And such increase in CRC incidence is corresponding with the increasing
incidence of CRC-associated comorbidity and adoption of a westernized lifestyle in China.
Therefore, understanding the role of these factors may suggest additional prevention strategies
that can reduce the incidence of CRC.
Several aspects of risk factors for CRC, including inherited genetic variation [
4
], lifestyle
factors [
5,6
], comorbidity [7] and the lifetime number of stem cell divisions [
8
], have been studied
on different levels. In this study, we mainly paid our attention to the joint effects of lifestyle
factors and comorbidity on CRC risk. In terms of lifestyle factors, there are various known and
putative ones including cigarette smoking [
9,10
], alcohol consumption [
11,12
], vegetable
intake [
6
], red meat consumption [
13
], physical activities [
14
], sleep [
15–17
] and obesity
[
18,19
]. Meanwhile, several kinds of comorbidity are also linked to an increasing risk of CRC
such as chronic gastritis [
20–22
], schistosomiasis [23], inflammatory bowel disease (IBD)[
24
],
polyps [
25
], diabetes [
26,27
], hyperglycemia and hypertension [
28,29
].
All these evidence suggests the multi-factorial nature and preventive potential of CRCs with
optimal lifestyle and well-controlled comorbidity. However, to our knowledge, no study has
been done to determine the joint effects of lifestyle factors and comorbidity on colorectal
carcinogenesis, especially in China. Given this condition, we embark on the present case-control
study with a view to assess the potential influence of several factors on CRC in Chinese
population more precisely. And we established Healthy Lifestyle Index (HLI) and Comorbidity
History Index (CHI) to evaluate possible synergistic effects of lifestyle factors and comorbidity on
the risk for CRC.
Materials and Methods
Study population
Colorectal cancer cases were drawn from a database of the Songjiang Center of Shanghai
Mun (...truncated)