Emory Study Links Risks of Death from Injury to Socioeconomic Status
ATLANTA -- Being a blue collar worker such as a trash collector or a
maid, rather than a white collar professional such as a teacher or lawyer,
doubles a person's odds of dying from violent injury, says a new study
that analyzes causes of death and employment categories for more than
a quarter-million Americans. And the effect is even stronger for men
than it is for women.
The findings of Kyle Steenland,
PhD, professor of environmental and occupational health at Emory Universityís
Rollins School of Public Health, and colleague s from the National Institute
for Occupational Safety and Health and New Jersey Medical School were
published in the January issue of the Epidemiology journal.
Dr. Steenland used occupational
mortality data from death certificates in a program coordinated by the
National Institute for Occupational Safety and Health and data from
the US Census to estimate the association between socioeconomic status
and deaths from external causes, which includes motor vehicle accidents,
suicide, homicide, medical complications, and non-vehicular injuries.
For both men and women aged 20 to 64, all major categories of death
from these external causes are related to socioeconomic status (SES).
The results show a strong trend of fewer deaths with higher socioeconomic
status and higher deaths with lower socioeconomic status.
"Deaths from external causes
are usually preventable and are the second leading cause of years of
life lost for persons under age 75, just behind cancer," Dr. Steenland
says. "We show that these causes are strongly related to socioeconomic
status. Those in the lower quarter of socioeconomic status die at a
rate twice that of those in the upper quarter of socio-economic status."
A total of 261,723 deaths
were measured in 27 states from 1984-1997 among employed persons aged
20-64. Occupations were determined by listings on death certificates
and Nam-Powers scores were used to measure socioeconomic status. (Nam-Power
scores are well-known and commonly used scores based on the income and
education levels associated with each occupation enumerated in the U.S.
The scores were then divided
into four quartiles, with the first quartile representing the lowest
socioeconomic status and the fourth quartile the highest socioeconomic
For men and women combined,
40% of motor vehicle fatalities can be attributed to being in the lower
3/4 of SES versus the top quartile SES. In addition, 32% of suicides,
51% of homicides and 40% of deaths from other injuries can be attributed
to having an SES status below the top quartile.
"Approximately 41% of the
measured deaths would be preventable if those in the lowest three quartiles
of socioeconomic status had the same income and education as those in
the top quartile of socioeconomic status," Dr. Steenland says. "But
there are lots of reasons why the less advantaged die more of external
causes ≠ less access to mental health care, unsafe working and living
conditions, and more exposure to violent crime. All these factors can
be improved if society as a whole wishes to make these changes."
The data reflect a stronger
and more consistent SES effect among males than females. Males had a
three to four times higher death rate due to external causes than females.
Dr. Steenland suggests that the factors that increase deaths from external
causes in men, such as higher rates or alcohol abuse, higher crime rates,
and more work-related fatalities, are factors associated with SES. Dr.
Steenlandís research also concluded that:
- Men in the lowest quartile
had a mortality rate from external causes almost three times higher
than men in the highest quartile.
- Women in the lowest quartile
had 58% higher rate of mortality than women in the highest quartile.
- Blacks had a 74% higher
rate of death from all external causes when compared to whites.
- Homicide rates in the
data in the entire U.S. began decreasing in the 1990s, parallel with
an improving U.S. economy, and parallel to a decrease in all serious
"Often we in the scientific
and medical community focus on details of one disease or one treatment,
failing to look at the big picture," Dr. Steenland says. "Facing up
to inequalities in death rates may force us to see the dramatic impact
of inequalities in our daily lives."
N. Kyle Steenland, Ph.D.
conducts research in occupational and environmental epidemiology. Dr.
Steenland also works on issues of epidemiologic methods and risk assessment.
Recently he has begun new work in the area of social epidemiology, studying
the relation of socioeconomic status to cancer and heart disease.
*Examples of occupations
in each socioeconomic quartile include: first quartile-
maids, roofers, garbage collectors; second quartile -
bartender, truck driver, carpenter, auto mechanic; third quartile-
postal clerk, secretary, car salesman; fourth quartile
- registered nurse, elementary teacher, lawyer, doctor