colorectal cancer ( crc ) remains the second leading cause of cancer deaths in the united states ( us ) ( 1 ) , despite the high survival rate from early treatment ( 2 ) .
it is estimated that 136830 new cases of colorectal cancer will be recorded in 2014 in the us and 50310 of these cases will die from the disease ( 3 ) .
cancer of the colon and rectum affects both males and females equally , and the risk increases with age ( 3 , 4 ) .
the survival rate for colorectal cancer is very low at late diagnosis of the disease .
five - year survival rates as high as about 90% have been reported for tumors detected and removed before extension ( 2 ) .
evidence also indicates a reduction in the survival rate to about 70% for tumors which have already extended , and as low as 13% when metastasis has already occurred ( 2 ) .
decline in crc mortality rates in the us has been attributed to early detection and surgical removal of the tumor before metastasis ( 5 ) .
early detection and early treatment are possible due to the availability of effective and relatively inexpensive crc screening tests ( 6 ) .
a clinical trial showed 33 and 43% reductions in incidence and mortality of crc respectively as result of a single sigmoidoscopy screening of adults between 55 and 64 years ( 7 ) . in the us
, crc screening is covered by most health plans and there is a published guideline for crc screening ( 8) .
however , uptake of crc screening is relatively low , and it is about 50% of those for whom the test is highly recommended ( 9 - 11 ) . this calls for public health efforts to increase awareness , acceptance and uptake of crc screening , especially for those with increased risk .
reported predictors of crc screening include age , educational level , income level , and health insurance status ( 9 , 12 ) .
it therefore raises questions about the low uptake of crc compared to screening programs for other cancers .
this calls for more investigation into predictors of crc screening uptake to inform policy and intervention planning .
the link between depression , alcohol and tobacco use ; and screening uptake have also been investigated .
a study investigated the influence of depression on other cancer screening among breast cancer survivors in latino .
a recent survey in washington state in the us identified depression as a significant barrier to cervical cancer screening uptake ( 14 ) .
however , kaida and co - workers ( 15 ) observed that age played an important role in the relationship between depression and cervical cancer screening .
in contrast , kodl and co - workers observed a significant increase in crc uptake among those with mental health diagnosis in a bivariate analysis ( 16 ) .
however , inverse association was observed when they controlled for timing of diagnosis and outpatient visits .
, it was observed that lower depression indirectly increases uptake of crc screening through a better self - rated health ( 17 ) .
these findings call for more investigation into the relationship between mental health and crc screening to inform policy and intervention .
however , to the best of our knowledge , the relationship between insomnia and crc screening uptake has not yet been evaluated . again
, racial differences in the influence of depression on crc screening have not yet been evaluated .
we examined the influence of and racial differences in depression , insomnia , alcohol use , and tobacco use on crc screening uptake in the usa .
the national health interview survey ( nhis ) is a multi - purpose health survey which is conducted by the national center for health statistics ( nchs ) , center for disease control and prevention ( cdc ) .
it is a principal source of health information of the civilian noninstitutionalized household population of the us .
public - use data files are released annually and can be accessed from the internet . from each family in the nhis ,
one adult aged 18 years or older is randomly selected to respond to sample adult core questionnaires .
the 2012 nhis sample is the largest sample size since the current sampling strategy came into force in 2006 .
analysis of 2012 data from the national health information survey ( nhis ) was done to determine associations between depression , insomnia , alcohol use and tobacco use , and colorectal cancer screening in participants .
information on depression , insomnia , alcohol use and tobacco use was self - reported .
participants were considered to have had a crc screening ( case ) if they responded 
yes  to the question  test for colon cancer , past 12 months  ( table 1 )
demographic variables collected and used in this analysis included age , classified as young ( 18 - 44 years ) , middle aged ( 45 - 64 years ) , and elderly ( 65 years or older ) ; gender ; race / ethnicity ( white , african american ( aa ) , asian and other )
. marital status was classified into married / living with partner ; widowed / divorced / separated ; and single .
alcohol consumption was classified as never , current light or moderate drinking , and past drinking .
income level was categorized into low income ( 0 - 34999 usd ) , middle income ( 35000 - 74999 usd ) and high income (  75000 usd ) .  
population proportions in cases and controls of independent variables and demographic factors were estimated by proc surveyfreq procedure in sas .
proc surveymeans procedure was also used to estimate the overall prevalence of crc screening ; while sas proc surveyfreq was used to estimate the prevalence in potential factors .
odds ratios ( ors ) and their 95% confidence intervals ( cis ) were estimated for each of the suspected predictors of crc screening by prc surveylogistic procedure .
a multiple logistic regression was performed for all races combined and then stratified by race ( white and aa ) .
all the analyses were conducted with sas statistical software , version 9.2 ( sas institute , cary , nc , usa ) .
the national health interview survey ( nhis ) is a multi - purpose health survey which is conducted by the national center for health statistics ( nchs ) , center for disease control and prevention ( cdc ) .
it is a principal source of health information of the civilian noninstitutionalized household population of the us .
public - use data files are released annually and can be accessed from the internet . from each family in the nhis ,
one adult aged 18 years or older is randomly selected to respond to sample adult core questionnaires .
the 2012 nhis sample is the largest sample size since the current sampling strategy came into force in 2006 .
analysis of 2012 data from the national health information survey ( nhis ) was done to determine associations between depression , insomnia , alcohol use and tobacco use , and colorectal cancer screening in participants .
information on depression , insomnia , alcohol use and tobacco use was self - reported .
participants were considered to have had a crc screening ( case ) if they responded 
yes  to the question  test for colon cancer , past 12 months  ( table 1 ) .
subjects who answered  no  to the question served as controls . demographic variables collected and used in this analysis included age , classified as young ( 18 - 44 years ) , middle aged ( 45 - 64 years ) , and elderly ( 65 years or older ) ; gender ; race / ethnicity ( white , african american ( aa ) , asian and other ) .
marital status was classified into married / living with partner ; widowed / divorced / separated ; and single .
alcohol consumption was classified as never , current light or moderate drinking , and past drinking .
income level was categorized into low income ( 0 - 34999 usd ) , middle income ( 35000 - 74999 usd ) and high income (  75000 usd ) .   abbreviations : aa , african american .  
population proportions in cases and controls of independent variables and demographic factors were estimated by proc surveyfreq procedure in sas .
proc surveymeans procedure was also used to estimate the overall prevalence of crc screening ; while sas proc surveyfreq was used to estimate the prevalence in potential factors .
odds ratios ( ors ) and their 95% confidence intervals ( cis ) were estimated for each of the suspected predictors of crc screening by prc surveylogistic procedure .
a multiple logistic regression was performed for all races combined and then stratified by race ( white and aa ) .
all the analyses were conducted with sas statistical software , version 9.2 ( sas institute , cary , nc , usa ) .
there were 21511 participants included in the analysis , comprising 9542 ( 44% ) males and 11966 ( 56% ) females .
a higher percentage of males reported having crc screening in the last 12 months ( 54% vs. 46% ) . proportion of older adults was higher in cases than in controls ( 36% vs. 27% ) .
african - american ( aa ) adults and married also formed higher proportions in cases than in controls ( 13% vs. 10% , 70% vs. 66% , respectively ) . a higher proportion of cases had higher income than controls ( 41% vs. 36% ) .
table 2 illustrates the prevalence of crc screening by demographic factors and other independent variables .
the prevalence of crc screening in adults with cancer , depression and insomnia was significantly higher than those without the conditions ( 26% vs.18% ; 21% vs.18% ; and 21% vs.18% , respectively ) .
prevalence of crc screening was highest in past smokers compared to current smokers and never smokers ( 23% vs. 16% vs. 18% ) .
participants with past alcohol use recorded the highest prevalence of crc screening compared to current and never alcohol users ( 20% vs.19% vs. 16% ) .  
results of both univariate and multiple logistic regression analyses of the association between crc screening and all factors included in the model are shown in table 3 .
there were significant associations between crc screening and all factors examined in the unadjusted analysis ( p < 0.05 ) .
adjusting for all other factors , cancer history ( or = 1.51 , 95%ci = 1.32 - 1.73 ) ; moderate alcohol drinking ( or = 1.16 , 95%ci = 1.01 - 1.30 ) ; past smoking ( or = 1.17 , 95%ci = 1.04 - 1.32 ) ; depression ( or = 1.37 , 95%ci = 1.18 - 1.58 ) ; aa race ( or = 1.74 , 95% ci = 1.53 - 1.98 ) and insomnia ( or = 1.18 , 95%ci = 1.06 - 1.32 ) were all positively associated with crc screening .
females ( or = 0.73 ; 95% ci = 0.66 - 0.82 ) and single ( or = 0.78 , 95% ci = 0.66 - 0.91 ) were inversely associated with crc screening prevalence . compared to young adults ( 18 - 44 years ) ,
screening was significantly higher in middle - aged and the older adults (  65 ) ( or = 2.91 , 95%ci = 2.35 - 3.62 and or = 3.76 , 95%ci = 2.99 - 4.74 , respectively ) .
compared to low income earners ( 0 - 34999 usd ) , crc screening was significantly higher in middle income ( 35000 - 74999 usd ) and high income (  75000 ) earners ( or = 1.32 , 95% ci = 1.17 - 1.48 ; and or = 1.50 , 95% ci = 1.31 - 1.73 , respectively ) .  
abbreviations : aa , african american ; or , odds ratio ; ci , confidence interval .  
adjusting for all other factors , age , income and depression showed significant positive association with crc screening in both whites and aas . in both races , females were less likely to screen for crc . while the single were significantly less likely to receive crc screening among whites ( or = 0.75 , 95%ci = 0.61 - 0.92 ) , marital status was not significantly associated with crc screening among aa ( p > 0.4 ) .
cancer history was positively associated with crc screening in whites ( or = 1.55 , 95%ci = 1.33 - 1.79 ) but not significant in aas ( p > 0.1 ) .
there was a 47% significant increase in crc screening in past alcohol users among aas ( 95% ci = 1.06 - 2.09 ) but alcohol use was not associated with crc screening in whites ( p > 0.1 ) . in both races ,
crc screening was slightly but not significantly reduced in current smokers , however , past smoking was positively associated with crc screening in whites ( or = 1.29 , 95% ci = 1.09 - 1.53 ) but not in aas .
history of insomnia also increased crc screening in whites ( or = 1.17 , 95% ci = 1.03 - 1.34 ) but it was not significantly associated with crc screening in aas .  
abbreviations : aa , african american ; or , odds ratio ; ci , confidence interval .  
there were 21511 participants included in the analysis , comprising 9542 ( 44% ) males and 11966 ( 56% ) females .
a higher percentage of males reported having crc screening in the last 12 months ( 54% vs. 46% ) . proportion of older adults was higher in cases than in controls ( 36% vs. 27% ) .
african - american ( aa ) adults and married also formed higher proportions in cases than in controls ( 13% vs. 10% , 70% vs. 66% , respectively ) . a higher proportion of cases had higher income than controls ( 41% vs. 36% ) .
table 2 illustrates the prevalence of crc screening by demographic factors and other independent variables .
the prevalence of crc screening in adults with cancer , depression and insomnia was significantly higher than those without the conditions ( 26% vs.18% ; 21% vs.18% ; and 21% vs.18% , respectively ) .
prevalence of crc screening was highest in past smokers compared to current smokers and never smokers ( 23% vs. 16% vs. 18% ) .
participants with past alcohol use recorded the highest prevalence of crc screening compared to current and never alcohol users ( 20% vs.19% vs. 16% ) .  
results of both univariate and multiple logistic regression analyses of the association between crc screening and all factors included in the model are shown in table 3 .
there were significant associations between crc screening and all factors examined in the unadjusted analysis ( p < 0.05 ) . adjusting for all other factors , cancer history ( or = 1.51 , 95%ci = 1.32 - 1.73 ) ; moderate alcohol drinking ( or = 1.16 , 95%ci = 1.01 - 1.30 ) ; past smoking ( or = 1.17 , 95%ci = 1.04 - 1.32 ) ; depression ( or = 1.37 , 95%ci = 1.18 - 1.58 ) ; aa race ( or = 1.74 , 95% ci = 1.53 - 1.98 ) and insomnia ( or = 1.18 ,
females ( or = 0.73 ; 95% ci = 0.66 - 0.82 ) and single ( or = 0.78 , 95% ci = 0.66 - 0.91 ) were inversely associated with crc screening prevalence . compared to young adults ( 18 - 44 years ) , screening was significantly higher in middle - aged and the older adults (  65 ) ( or = 2.91 , 95%ci = 2.35 - 3.62 and or = 3.76 , 95%ci = 2.99 - 4.74 , respectively ) . compared to low income earners ( 0 - 34999 usd ) , crc screening was significantly higher in middle income ( 35000 - 74999 usd ) and high income (  75000 ) earners ( or = 1.32 , 95% ci = 1.17 - 1.48 ; and or = 1.50 , 95% ci = 1.31 - 1.73 , respectively ) .  
abbreviations : aa , african american ; or , odds ratio ; ci , confidence interval .  
adjusting for all other factors , age , income and depression showed significant positive association with crc screening in both whites and aas . in both races , females were less likely to screen for crc . while the single were significantly less likely to receive crc screening among whites ( or = 0.75 , 95%ci = 0.61 - 0.92 ) , marital status was not significantly associated with crc screening among aa ( p > 0.4 ) .
cancer history was positively associated with crc screening in whites ( or = 1.55 , 95%ci = 1.33 - 1.79 ) but not significant in aas ( p > 0.1 ) .
there was a 47% significant increase in crc screening in past alcohol users among aas ( 95% ci = 1.06 - 2.09 ) but alcohol use was not associated with crc screening in whites ( p > 0.1 ) . in both races ,
crc screening was slightly but not significantly reduced in current smokers , however , past smoking was positively associated with crc screening in whites ( or = 1.29 , 95% ci = 1.09 - 1.53 ) but not in aas .
history of insomnia also increased crc screening in whites ( or = 1.17 , 95% ci = 1.03 - 1.34 ) but it was not significantly associated with crc screening in aas .  
abbreviations : aa , african american ; or , odds ratio ; ci , confidence interval .  
in the combined analysis , increasing age , high income , being male , depression , insomnia , past smoking , moderate alcohol drinking , and aa race were all associated with increased crc screening .
crc screening prevalence was significantly reduced in the single compared to the married or living with partner . in a stratified analysis by race groups , significant differences in crc screening predictors were observed between whites and aas .
there was a significant increase in crc screening with increasing age , increasing income level , and depression in both races .
similar to the combined analysis , females were less likely to screen for crc in both whites and aas .
cancer history , marital status , and insomnia were associated with crc screening in whites but not in aas .
past alcohol drinking increased screening in aas but alcohol was not associated with screening in whites .
the relationship between age , gender , income level and crc screening have been widely reported in the literature , and our findings are in line with those already reported ( 9 , 12 ) . however , in contrast with findings in the literature ( 9 , 12 ) , our analysis found a significant increase in crc screening among aas compared to whites .
this increase may stem from perception of risk . though our analysis can not fully explain why crc screening is higher in aas than whites , it is important to note that incidence of and mortality from crc have been reported to be higher in aas than all other racial / ethnic groups in the usa ( 20 - 24 ) .
awareness of this statistics can trigger uptake of screening as has been shown previously ( 25 ) .
the observation that moderate alcohol drinking was associated with increase crc screening is similar to previously reported influence of alcohol consumption on mammography ( 26 ) .
however , our results indicate that the relationship between moderate alcohol drinking and cancer screening may be race - dependent . when stratified by race , the observed 16% increase in crc screening in moderate alcohol consumption completely attenuated .
it resulted in 47% significant increase in crc screening among past alcohol users but only in aas .
we have found no significant difference in crc screening between current and never smokers in contrast to earlier finding that smoking reduces cancer screening ( 27 , 28 ) . in line with a previous report ( 10 ) , we found past smoking to increase crc screening in the combine analysis .
it suggests that campaigns to increase smoking cessation may also lead to improvement in healthy behaviors .
our findings on depression contrast most of the evidence reported earlier ( 13 - 15 , 29 ) .
number of outpatient visits has been found to mediate mental illness and health behavior ( 16 ) .
we are unable to attribute the observed influence of depression to physician visit based on our data , however , it is more plausible for depressed individuals to have increased contact with care providers ( 16 ) and the result may reflect the importance of health care provider contacts and screening uptake
. this may also apply to those who reported symptoms of insomnia in the last 12 months .
insomnia may affect up to 50% of patients with cancer and increases cancer symptom burden and impairs quality of life ( 18 , 30 - 33 ) .
however , to the best of our knowledge , this study is the first to examine the relationship between insomnia and crc screening uptake .
we found that insomnia was positively associated with crc screening and the associations showed race difference . of significant important
though our data is limited to explain these differences , it suggests that race specific interventions may be important in improving uptake of crc screening
. however , further studies on these variations may be important to explain the difference .
since information from participants was self - reported , our study may suffer from a recall bias as well as social desirability bias .
however , recall bias is likely to be minimal since information collected was within one year . in conclusion , cancer history , smoking status , insomnia and alcohol intake status
may influence crc screening uptake differently between whites and aas . to improve overall crc screening uptake in the us ,
it is important to consider racial differences in predictors and tailor appropriate interventions to each racial / ethnic group .
 background : mortality from colorectal cancer ( crc ) can be reduced drastically by early detection and early treatment . 
 however , uptake of crc screening is relatively low , about 50% for those whom the test is highly recommended.objectives:we examined the influence of and racial differences in depression , insomnia , alcohol use , and tobacco use on crc screening uptake in the us.patients and methods : analysis of the 2012 national health information survey data was conducted . 
 both weighted univariate and multiple logistic regression analyses were performed in sas to estimate the odds ratios ( ors ) and their 95% confidence intervals ( cis ) . a total of 21511 participants were included in the analysis.results:prevalence of crc screening in the participants was 19% . adjusting for all factors , insomnia ( or = 1.18 , 95%ci = 1.06 - 1.32 ) , moderate alcohol drinking ( or = 1.16 , 95%ci = 1.01 - 1.30 ) , past smoking ( or = 1.17 , 95%ci = 1.04 - 1.32 ) , depression ( or = 1.37 , 95%ci = 1.18 - 1.58 ) , african american ( aa ) race , and cancer history were positively associated with crc screening . females and single were inversely associated with crc screening prevalence . in stratified analysis by races ( white and aa ) , depression was associated with crc screening in both races . 
 marital status , smoking , cancer history and insomnia were associated with crc screening in whites only ; while alcohol use was associated with crc screening in aas only.conclusions:we have found significant associations between lifestyle factors ( alcohol consumption and smoking ) and mental health problems ( depression and insomnia ) and crc screening uptake . to improve overall crc screening uptake in the us , 
 it is important to consider racial differences in predictors and tailor appropriate interventions to each racial / ethnic group . 