In class we’ve discussed many aspects of cancer. Some
of these had to do with the most prevalent types of cancer in the United
States, the survival rates, treatments, cancer risks, and many other related
topics. There is one possible related risk factor which we did not discuss:
socioeconomic status of the patient. In an article titled, Impact of Socioeconomic Status on cancer incidence and stage at diagnosis, scientists explore the relationship between socioeconomic status and
cancer incidence. Combining data from the Surveillance, Epidemiology, and End
Results (SEER) Program at the National Cancer Institute, a population-based
cancer registry, and the US representative National Longitudinal Mortality
Study (NLMS), which provides self-reported demographic and socioeconomic data, researchers
were able to examine the connection between the two.
Socioeconomic status is still very prevalent in
cancer incidence, despite all of the advances in identifying risk factors and
treatment for the disease. In fact, since so many disadvantaged groups were
suffering from cancer at a larger rate, Congressional legislation was prompted
and the NIH (National Institutes of Health) Center for Minority Health and
Health Disparities was established. The NLMS data had to be used with that of
the SEER Program because individual socioeconomic status (SES) – for example, education,
occupation, and income – are not obtained by SEER. They have had to rely more
on aggregate ecological data. This study used the record linkages to assess
cancer incidence, tumor characteristics, and patient survival, based on
race/ethnicity, immigrant status, health status, and health care access (availability
of health insurance).
The study begins with researchers matching SEER
cancer patient records to NLMS records for patients diagnosed between 1973 and
2001. The SEER registries included the states of Connecticut, Hawaii, Iowa,
Kentucky, Louisiana, and Utah; the areas of Detroit, Los Angeles, Northern
California (the greater bay area), and Seattle; and greater California
(excludes L.A. and Northern California). They used an algorithm to match the
reports using social security numbers, names, and birth dates. In total, they
compared 2.4 million NLMS records with 4,172,139 patient records in SEER
registries, for a total of 26,844 patient matches. Of these, 2,663 patients
were diagnosed with more than one primary cancer, resulting in a total of 29,883
primary cancers diagnosed. Some patients had to be excluded because of various
problems with follow-up information, residency, or diagnoses too late for
follow-ups.
All of the demographic and socioeconomic variables
used are from self-reports, except age, stage, and sex at diagnosis. There were
five categories of educational level used: less than high school, high school
graduate, some post high school education, college education or beyond, and unknown.
Employment status was classified into five categories: employed, unemployed,
retired, unable to work, and outside the labor force. Both of these
classifications are shown in the tables.
Incidence analyses were performed for all cancers
combined and for six major cancers separately: colon/rectum, breast, lung,
uterine cervix, prostate, and melanoma. Age specific cancer incidence rates
were calculated and adjusted using the age composition of the 2000 US standard
population. Only the first primary cancer diagnosed in a patient was counted,
regardless of cancer site, and follow-up time was allowed to accumulate only
until the date of diagnosis of the first cancer.
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| Table 1 |
The tables show specific cancer incidence with
relation to the socioeconomic factors I’ve described above. Table 1 above shows the
data for all cancers combined to show how the total cancer incidence burden
varies by socioeconomic characteristics. There were many correlations between various
factors and specific cancer incidence. For example, as shown in Table 2 below, men
with a less than high school education and those with a high school education
had lung cancer rate ratios of 3.01 and 2.32, compared to those who were
college-educated. In Table 3 below, compared with the college-educated, men and women with less than a high school
education had ratios of 0.79 and 0.74 for prostate and breast cancer incidence.
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| Table 2 |
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| Table 3 |
Income gradients in male and female lung cancer
incidence were significant as well, with those with incomes less than $12,500
having a greater incidence rate than those with incomes above $50,000. However,
what’s interesting is that men with lower incomes were at reduced risk when
compared to those with an income greater than $50,000.
Overall, Hispanics and Asian/Pacific Islanders had
significantly lower incidence rates for all cancers, when compared with
non-Hispanic whites (Tables 2, 3, 4). When comparing non-Hispanic whites with
non-Hispanic blacks, those who were black had a higher overall cancer rate,
with specifically higher rates of lung and prostate cancer.
For the first time, these researchers have
demonstrated disparities in cancer incidence and socioeconomic status for a
large portion of the United States. The racial and ethnic patterns in cancer
incidence found in this study are consistent with those obtained from other
data. Interestingly, there was a significantly lower rate of cancer incidence in
those who were Asian/Pacific Islander or Mexican when compared with those who
were non-Hispanic blacks and in lower education and income brackets.
Some of the social inequalities in cancer incidence
may be related to other socioeconomic and demographic differences in risk
factors – for example, cigarette smoking, poor diet, physical inactivity,
obesity, or sun exposure. Also, disparities in health care access and
availability (like cancer screening) may contribute to differences in cancer
deaths. Those who have a lower socioeconomic status are more likely to smoke or
be obese. However, these may not always be an accurate sign of cancer incidence
because some risk factors, or other things which affect socioeconomic status, can
be encountered over a period of time (like educational level) which can’t be
directly contributed to a certain area.
I think that this examination into the relationship
between socioeconomic status and cancer incidence only further seconds the
hypotheses that have been made regarding health care in the United States. Usually,
those who are less fortunate and are in the lower income bracket tend to have
more health risks, either because they don’t have access to preventative care
or are just more likely to engage in risky behavior. I do think it’s strange, however,
the study mentions that when examining those who reside in the SF Bay area,
breast and prostate cancer have larger incidence when socioeconomic status
increased. Following my past comment and the general findings of the study, one
would think that they would be lower. This leads me to believe that something
else is playing a role in the incidence of breast and prostate cancer, something
which is closely related to those with a higher socioeconomic status. This
sector of the population must be more likely to engage in certain risk factors
which lead to these incidences. What this could be is unknown, but it could be
contributed to the food they eat (maybe these people are more likely to eat
fast food because of busier schedules) or even general stress they may endure.
I’m curious as to how the government will go about
developing new policies to combat this growing disparity between socioeconomic
status and cancer incidence. Will these findings mean anything to policymakers?
It’s important to note that these findings can also be applied to the rest of
the health care world. More often than not, those with a lower socioeconomic
status are more likely to suffer from detrimental health problems because of
their decreased access to health care and, perhaps more importantly, preventative
health care.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2711979/pdf/nihms-104105.pdf
