Colorectal cancer (CRC) is highly preventable with screening, yet it remains the third leading cause of cancer death in both men and women [
The literature on CRC screening and weight status in large, nationally representative samples is contradictory. In the 1997 Cancer Prevention Nutrition cohort, Chao et al. observed lower rates of CRC screening in overweight men, overweight women, obese men, and obese women in comparison to their normal weight peers [
In the 2000 National Health Interview survey (NHIS) data, Wee et al. found a trend towards increased screening in the overweight population compared to their normal weight counterparts, but this analysis did not examine obesity and overweight separately in relation to CRC screening, nor did the analysis address the relationship of race/ethnicity and gender with screening [
This paper seeks to address limitations of prior analyses by examining race/ethnicity and gender, along with weight status, in CRC screening. This analysis uniquely includes Hispanics and reports weight status in terms of normal, overweight, and obese. Thus, findings presented here provide a more comprehensive view of factors which may impact CRC screening use than has been reported in the literature to date [
This study analyzed the data from the 2005 National Health Interview Survey, a nationally representative, cross-sectional, household survey of the civilian noninstitutionalized population of the United States [
NHIS respondents in this study were individuals aged 50 to 80 years old [
The sampling plan follows a multistage area probability design that permits the representative sampling of households and noninstitutional group quarters (e.g., college dormitories) and oversamples of blacks, Hispanics, and Asians. This complex survey design allows for population estimates of the United States [
We examined the self-reported variables related to endoscopy and stool blood testing and test date. The outcome variable of overall CRC screening status (up to date or not) was defined as up to date in individuals who had one of the following screening tests: colonoscopy within the last 10 years, sigmoidoscopy in last 5 years, or FOBT within the last year [
Obesity was defined according to BMI which was calculated as weight in kilograms divided by the square of height in meters. BMI was categorized as underweight (<18.5), normal weight (18.5–24.9), overweight (25–29.9), and obesity (≥30) [
We examined the potential confounding variables of age (50–59, 60–69, 70–79), marital status (married, unmarried), education (<12 y, high school graduate, some college, college graduate), annual income (<20 K, >20 K), regular source of medical care (yes/no), insurance status (yes/no), office visits in the last year (none, 1, 2–5, ≥6), personal history of cancer (yes/no), alcohol consumption (heavy, light, none), health status (fair/poor, excellent/good), smoking status (current, former, never), physician recommendation (yes/no), number of comorbidities (0, 1, 2-3, 4-5, 6 or more), and physical recreational activity as metabolic equivalents per week (none, <675 mets, ≥675 mets).
In univariable analyses, we computed the proportion of subjects who had CRC screening across levels of each of the variables listed above (and shown in Table
Colorectal cancer screening according to selected covariates (
Variable | CRC screening rate (weighted) | Unadjusted odds ratio [CI95] | Adjusted odds ratio [CI95]1 |
---|---|---|---|
Overall | 55.8 | ||
Weight status | |||
aNormal weight | 56.3 | ||
Overweight | 55.7 | 0.97 [0.86–1.11] | 1.00 [0.84–1.21] |
Obese | 55.5 | 0.98 [0.85–1.12] | 0.91 [0.75–1.12] |
Gender | |||
aFemale | 55.7 | 0.99 [0.89–1.10] | 0.86 [0.73–1.02] |
Male | 56.0 | ||
Race | |||
aHispanic | 38.2 | ||
Black | 46.1 | 1.38 [1.06–1.81] | 1.26 [0.87–1.82] |
White | 58.5 | 2.28 [1.85–2.80] | 1.25 [0.96–1.63] |
Age | |||
a50–59 | 47.2 | ||
60–69 | 62.7 | 1.87 [1.67–2.11] | 1.69 [1.41–2.02] |
70–79 | 65.0 | 2.08 [1.79–2.41] | 1.71 [1.39–2.10] |
Marital status | |||
aUnmarried | 51.6 | ||
Married | 57.5 | 1.27 [1.15–1.41] | 1.02 [0.86–1.20] |
Education | |||
| 44.6 | ||
High school graduate | 53.3 | 1.41 [1.21–1.70] | 1.03 [0.83–1.28] |
Some college | 55.6 | 1.56 [1.32–1.84] | 1.01 [0.79–1.29] |
College graduate | 65.3 | 2.33 [1.96–2.78] | 1.42 [1.09–1.85] |
Annual income | |||
| 45.0 | ||
>20 K | 58.0 | 1.69 [1.48–1.93] | 1.31 [1.05–1.63] |
Regular source of medical care2 | |||
aNo | 28.5 | ||
Yes | 57.4 | 3.38 [2.57–4.44] | 1.11 [0.78–1.57] |
Insured | |||
aNo | 22.7 | ||
Yes | 57.9 | 3.78 [3.02–4.73] | 1.57 [1.16–2.14] |
Office visits in last year | |||
aNone | 24.4 | ||
One | 43.3 | 2.37 [1.78–3.16] | 1.21 [0.83–1.77] |
2–5 visits | 58.4 | 4.35 [3.39–5.59] | 1.60 [1.14–2.27] |
≥6 visits | 64.9 | 5.74 [4.44–7.42] | 2.05 [1.42–2.96] |
Physician recommendation3 | |||
Yes | 81.9 | 43.49 [36.82–51.36] | 36.97 [31.18–43.84] |
aNo | 9.4 | ||
Health status | |||
aFair/Poor | 56.5 | ||
Excellent/Good | 52.8 | 1.16 [1.01–1.33] | 1.12 [0.91–1.38] |
Comorbidities | |||
a0 | 43.7 | ||
1 | 55.3 | 1.60 [1.38–1.85] | 1.18 [0.94–1.48] |
2-3 | 62.4 | 2.14 [1.85–2.48] | 1.28 [0.99–1.65] |
4-5 | 62.3 | 2.13 [1.73–2.62] | 1.20 [0.85–1.70] |
6 or more | 73.4 | 3.55 [2.29–5.53] | 2.28 [1.14–4.56] |
Personal history cancer ever | |||
aNo | 69.3 | ||
Yes | 53.5 | 1.96 [1.67–2.30] | 1.15 [0.92–1.43] |
Alcohol consumption4 | |||
aHeavy | 51.6 | ||
Light | 59.1 | 1.23 [0.93–1.63] | 1.01 [0.72–1.41] |
None | 54.0 | 0.91 [0.69–1.20] | 1.03 [0.73–1.45] |
Smoke | |||
aCurrent | 55.0 | ||
Former | 62.6 | 2.28 [1.93–2.70] | 1.27 [1.03–1.58] |
Never | 42.4 | 1.67 [1.43–1.94] | 1.26 [1.03–1.54] |
Recreational physical activity (METS) | |||
aNone/unable to exercise | 48.1 | ||
<675 | 59.4 | 1.58 [1.39–1.79] | 0.97 [0.81–1.17] |
≥675 | 69.9 | 1.84 [1.61–2.09] | 1.19 [0.98–1.44] |
1Adjusted for all covariates listed in first column
2Recoded from NHIS data, has a usual place of care which is not the emergency room
3Saw physician in last 12 months and received a recommendation for either colonoscopy or endoscopy
4Heavy ≥14 drinks/week, light = 1–14 drinks/week
The final sample included 7,088 individuals. Overall, CRC screening was up to date in approximately 56% of respondents. Weighted CRC screening rates among NHIS respondents were as follows: white males (58%), white females (58%), black males (44%), black females (48%), Hispanic males (39%), and Hispanic females (37%).
Table
Obesity was categorized further as obesity class I, II, and III, and there was no effect (data not shown). This classification could not be carried through in subgroups due to sample size. We also examined endoscopy and FOBT as separate outcomes and found no differences (data not shown).
Table
Adjusted model for colorectal cancer screening according to race/gender and ethnicity (
Weight status | CRC screening rate | Adjusted odds ratios1 | 95% confidence interval |
---|---|---|---|
Stratum specific for race/gender | |||
White males ( | 58.6 | ||
Normal | 59.7 | 1.00 | |
Overweight | 57.9 | 0.90 | 0.68–1.18 |
Obese | 59.0 | 0.83 | 0.61–1.13 |
Black males ( | 43.8 | ||
Normal | 45.5 | 1.00 | |
Overweight | 44.2 | 1.07 | 0.62–1.85 |
Obese | 42.1 | 1.06 | 0.56–2.02 |
Hispanic males ( | 39.4 | ||
Normal | 37.6 | 1.00 | |
Overweight | 35.0 | 0.71 | 0.37–1.37 |
Obese | 52.1 | 0.97 | 0.47–2.03 |
White females ( | 58.3 | ||
Normal | 58.3 | 1.00 | |
Overweight | 59.9 | 1.11 | 0.84–1.46 |
Obese | 56.5 | 0.91 | 0.68–1.21 |
Black females ( | 48.0 | ||
Normal | 36.2 | 1.00 | |
Overweight | 53.6 | 1.32 | 0.75–2.31 |
Obese | 48.1 | 1.16 | 0.64–2.10 |
Hispanic females ( | 37.1 | ||
Normal | 32.6 | 1.00 | |
Overweight | 34.6 | 0.88 | 0.47–1.64 |
Obese | 43.3 | 1.06 | 0.54–2.10 |
1Adjusted for all variables in Table
Obese and overweight individuals are as likely to receive CRC screening as their normal weight peers regardless of gender, race, or Hispanic ethnicity. This finding contradicts other literature which suggests a relationship between weight status and CRC screening. This study agrees with the recent analysis of Chang et al., who found no evidence that obese or overweight patients were less likely to receive recommended care, including CRC screening, when compared with their normal weight peers [
Findings presented here may be directly compared to a recent analysis which also examined the relationship of obesity and CRC screening in the NHIS 2005 data set [
The cross-sectional design of our study precludes determination of cause. BMI and CRC screening are self-reported and therefore may be distorted. Sample size is a challenge in analysis of our subgroups. Although all cells met the NHIS suggested requirements (less than 30% standard error), the wide confidence intervals suggest that sample size may have been a restriction in groups such as Hispanics. Additionally, we could not examine subclasses of obesity (i.e., obesity I, II, III) in our groups of interest due to sample size.
CRC screening reduces mortality and prevents colorectal cancer. However, rates of screening are unacceptably low overall and in minority subgroups. The rising prevalence of obesity and the higher burden of cancer risk in obese individuals make this an especially important population subgroup in terms of race/ethnicity, gender, and other characteristics.
There is no relationship between increasing weight and CRC screening in this nationally representative sample. Regardless of the lack of association of obesity and CRC screening, obesity remains a risk factor for increased morbidity/mortality related to CRC. Therefore, future work is needed to understand and mitigate risk in the obese population especially as this group comes to represent an ever-increasing percentage of the US population.