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The Prostate 39:23–27 (1999)
Prostate Cancer Mortality Trends in
Mexico, 1980–1995
Vı́ctor Tovar-Guzmán,* Carlos Hernández-Girón, Olga López-Rı́os, and
Eduardo C. Lazcano-Ponce
Center for Public Health Research, National Institute of Public Health, Cuernavaca, Mexico
BACKGROUND. In Mexico, prostate cancer (PC) is the second highest cause of mortality by
cancer in men. In 1991, there were 2,473 deaths, with a crude rate of 5.66 cases per 100,000 men
age 40 or over. For this same year, the ratio of proportional mortality to the total number of
malignant tumors was 12.6%. Our objectives were to determine the trends and geographic
distribution of mortality for PC in Mexico for 1980–1995.
METHODS. Crude and adjusted mortality rates were carried out for 1980–1995. A test for
trend was done using the simple lineal regression method. The standardized mortality ratio
(SMR) was calculated for 1980–1995 for each Mexican state.
RESULTS. The total number of deaths by PC in Mexico for 1980–1995 was 32,349. The crude
mortality rate increased during that period from 3.16 to 6.75 cases per 100,000 men over age
40. The statistical trend test with respect to time was significant (P < 0.0001). The state of
Southern Baja California showed a higher SMR, and a smaller SMR was shown for the state
of Quintana Roo.
CONCLUSIONS. The mortality trends for PC increased for the period studied. It represents
a serious problem for public health. We find that the central and northern states of the
country, characterized by a greater industrial and socioeconomic development, are those with
a higher SMR. Prostate 39:23–27, 1999. © 1999 Wiley-Liss, Inc.
KEY WORDS:
prostate cancer; mortality trends; Mexico
INTRODUCTION
Today, research on prostate cancer (PC) in Mexico
is limited. Some descriptive studies exist with respect
to the epidemiology of this disease, which mainly report the rapid increase in incidence and mortality, and
above all its appearance starting at age 45 years, with
an alarming rate in men 75 years and older.
In Mexico, PC is the second highest cause of mortality by cancer in men; the first is lung cancer. In 1991,
there were 2,473 deaths due to PC in Mexico, which is
equivalent to a crude rate of 5.66 cases per 100,000
men aged 40 or over. For this same year, the ratio of
proportional mortality to the total number of malignant tumors was 12.6%. For 1992, mortality rates by
state did not have a logical distribution pattern. The
state with the highest rate was Southern Baja California, and the one with the lowest rate was Quintana
Roo (6.4 and 1.1 per 100,000 inhabitants, respectively)
[1].
The objectives of our descriptive epidemiological
© 1999 Wiley-Liss, Inc.
research were to determine trends of specific crude
and adjusted mortality rates for PC in Mexico for
1980–1995, and their distribution by 5-year age groups
starting at age 40. Also, we calculated the value of the
standardized mortality ratio by state, which will provide information on the difference between observed
and expected cases. Another objective was to calculate
the correlation between specific mortality rates and
the socioeconomic level by state in Mexico.
MATERIALS AND METHODS
This work was carried out through an analysis of
information obtained from electronic records of PC
*Correspondence to: Dr. Victor Tovar-Guzmán, Center for Public
Health Research, National Institute of Public Health, Av. Universidad 655, Col. Sta. Marı́a Ahuacatitlán, Cuernavaca, Mor. C.P. 62508,
Mexico. E-mail: vtovar@insp3.insp.mx
Received 18 March 1998; Accepted 28 September 1998
24
Tovar-Guzmán et al.
Fig. 1. Mortality trends in prostate cancer among Mexican men, 1980–1995. Crude and age-adjusted rates. *P < 0.0001.
Fig. 2. Mortality trends by 5-year groups for prostate cancer in Mexico, 1980–1995. *P < 0.05.
mortality, edited by the National Statistics, Geography, and Informatics Institute (INEGI), which also integrates records such as age, state of residency, determinant cause of death (International Disease Classification (CIE) no. 185) and year of death [2]. For
calculations of crude mortality rates, was used as denominator the population projected by the National
Population Council (CONAPO). Adjusted mortality
rates for PC, for 1980–1995, were calculated according
to the direct statistical method, using the population of
the Mexican Republic as a reference [3,4].
The calculation of the statistical trend test, measured through the value of P, was done using the
simple lineal regression method, taking as a depen-
PC Trends in Mexico
25
Fig. 3. Standardized mortality ratios of prostate cancer by state in Mexico, 1980–1995.
dent variable the crude and adjusted mortality and, as
an independent variable, the year of death [5].
The crude cancer mortality rate trends by 5-year
groups, starting at age 40, were calculated using a
robust regression statistical technique, obtaining from
this the regression coefficient, 95% confidence interval, and statistical P value [6]. The working hypothesis
distinguishes the gradient, which is unequal to zero (␤
⫽ 0). The corresponding graph of rate trends was
done using the x-axis for the year of the study and the
y-axis for the corresponding rate. For this, the arithmetic scale was changed into a logarythmic one in
order to obtain a better understanding of the phenomenon under study.
The standardized mortality ratio (SMR) was calculated for 1980–1995 with a corresponding confidence
interval (CI) of 95% for each Mexican state. The SMR
is an intermediary step in the calculation of adjusted
statistical rates, using the indirect method [4].
Statistical analysis was carried out considering the
rural level, which was calculated by CONAPO using
different social indicators for the year 1990 for each
Mexican state [7] and the mortality rate due to PC.
Statistical analysis was carried out using the
STATA 3.1 [8] and EXCEL [9] packages.
RESULTS
The total number of deaths by PC in Mexico for
1980–1995 was 32,349, as recorded by death certificates. The crude mortality rate increased during that
period from 3.16 to 6.75 cases per 100,000 men over 40;
this represents an increase of 113.6% between 1980–
1995. The adjusted rate by age for the same period
varied between 2.71–7.01 cases per 100,000 men over
40, representing an increase of 191.9%. The statistical
trend test for the two rates with respect to time were
significant (P < 0.0001) (Fig. 1).
When analyzing mortality trends for each 5-year
age group, a statistically significant increase was observed in the slopes, starting from the 50–54-year age
group (P < 0.05). The greatest regression slope was for
the group of men older than 75 years, with a ␤ coefficient slope of 10.98 (P < 0.0001). The crude mortality
rate varied, and in the group of men 75 and older, it
26
Tovar-Guzmán et al.
TABLE 1. Standardized Mortality Ratio of Prostate Cancer by State in Mexico,
1980–1995*
State
BCS
Jalisco
Aguascalientes
Colima
Michoacán
Sonora
Zacatecas
Nayarit
Guanajuato
Chihuahua
Tabasco
Sinaloa
Coahuila
BCN
Tamaulipas
Distrito Federal
SMR
95% CI
State
SMR
95% CI
183.28
161.81
152.21
151.83
145.05
139.69
135.49
135.18
127.05
126.24
121.96
121.95
119.10
112.67
111.62
104.86
(158.36–208.18)
(156.18–167.44)
(136.15–168.27)
(132.78–170.88)
(138.35–151.74)
(131.32–148.07)
(124.99–146.00)
(122.88–147.48)
(120.93–133.18)
(119.14–133.34)
(111.90–132.02)
(114.69–129.21)
(111.27–126.92)
(104.05–121.28)
(104.90–118.35)
(101.78–107.93)
SLP
Nuevo León
Morelos
Yucatán
Querétaro
Tlaxcala
Hidalgo
Durango
Chiapas
Campeche
Veracruz
Puebla
Oaxaca
México
Guerrero
Quintana Roo
102.01
99.93
98.22
97.23
95.41
95.06
88.64
86.44
83.60
83.27
82.72
81.99
60.49
59.91
57.69
47.87
(94.96–09.06)
(94.41–105.46)
(89.21–107.22)
(89.23–105.22)
(84.74–106.09)
(83.13–106.99)
(81.77–95.50)
(78.47–94.40)
(77.78–89.42)
(71.30–95.24)
(79.29–66.16)
(77.43–86.56)
(55.94–65.04)
(57.46–62.36)
(52.89–62.49)
(35.86–59.89)
*SMR, standardized mortality ratio; 95% CI, 95% confidence interval.
increased from 170.1 in 1980 to 331.1 in 1995, which
represented an increase of 94% (Fig. 2).
The standard mortality ratio (SMR) for the different
Mexican states showed a dispersed relationship between the different regions, with higher SMRs in the
states of Southern Baja California (SMR, 183.28; 95%
CI, 158.36208), Jalisco (SMR, 161.81; 95% CI, 156.18–
167.44), and Aguascalientes (SMR, 136.15; 95% CI,
136.15–168.27). The smaller SMRs corresponded to the
states of Quintana Roo (SMR, 47.87; 95% CI, 35.86–
59.89), Guerrero (SMR, 57.69; 95% CI, 52.89–62.49),
and Mexico (SMR, 59.91; 95% CI, 57.46–62.36) (Table I,
Fig. 3).
A statistical analysis was carried out using mortality rate values for PC and rural level for 1990, which
gave us a value of r = −0.15 (P < 0.005), showing that
at higher rural levels, mortality rates were lower.
DISCUSSION
It is important to point out the change in the mortality behavior pattern that is occurring in Mexico. In
the last few decades, this has changed from a mortality
where causes were mostly infectious or due to deficiencies to a pattern of chronic diseases, particularly
cerebral-vascular and cancer. These causes are turning
into an important public health problem. In this context, PC is not an exception: its risks, characterized by
the influence of environmental and hormonal factors,
as well as life styles, have had an influence on the
incidence of the disease, with truly specific risk factors, such as its appearance in age groups older than
50 and primarily in the black race [10–13].
When analyzing SMR distribution in Mexico, we
found that the central and northern states of the country, characterized by greater industrial and socioeconomic development, were the ones with a higher
SMR, i.e., the number of observed cases was greater
than the number of expected cases, and this agrees
with the international literature, in the sense that this
type of cancer is more frequent in developed countries
[14–17].
In this study, we found an inverse determination
coefficient between rural level and crude PC rates.
This confirms what we stated above, that the states
with a higher rural level (Chiapas, Oaxaca, Campeche,
Guerrero, Tabasco, and Quintana Roo) are the ones
with lower rates for this kind of disease.
Environmental and geographic patterns, as well as
lifestyles that together become causes for PC, are distributed differentially throughout the Mexican regions; for example, the prevalence of determined risk
factors, such as lifestyles (a diet rich in saturated fats,
low physical activity, obesity, smoking, alcoholism)
are mainly manifested in the northern Mexican states.
These findings are similar to those reported in the
world literature [18–21].
A potential bias of mortality rates could be due to
the change in the quality of records. Some years ago,
there were problems in the notification and recording
of information, which created difficulties in diagnostic
certainty. Presently, due to state policies implemented
in the last several years, there is now greater certainty
in the statistics of secondary information on general
mortality.
PC Trends in Mexico
CONCLUSIONS
In Mexico, massive PC detection campaigns have
not yet been implemented. Techniques most often
used are rectal exploration by touch, transrectal ultrasonography, and serological markers [22]; these have
been mainly used in the diagnostic clinical phase. The
control and reduction of PC could be carried out in
two ways: 1) with a decrease in new cases, and 2)
through an increase in survival rates, through early
detection, and through improvements in treatment.
This would lead to a decrease in PC mortality.
In order to complement a better epidemiological
scenario for PC, it is important to carry out more descriptive and analytical research to obtain a better
comprehension of this problem.
REFERENCES
1. Olaiz G, Hernández M. Cáncer: un encuentro con el futuro epidemiológico. Cuadernos de Salud. Secretarı́a de Salud. México;
1994.
2. OPS. Clasificación internacional de enfermedades. IX revisión.
Washington, DC. 1978.
3. Lilienfield D, Stolley P. Foundations of epidemiology, 3rd ed.
New York: Oxford University Press; 1994.
4. Dever A. Epidemiologı́a y administración de servicios de salud.
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5. Daniel W. Bioestadı́stica. Base para el análisis de las ciencias de
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6. Hamilton L. Statistics with Stata 3. Belmont, CA: Duxbury Press;
1993.
7. Indice de marginación social. Mexico: CONAPO; 1990.
8. Stata Corporation. Stata release 3.1. College Station, MA: Stata
Corporation; 1993.
9. Microsoft Corporation. Microsoft Excel 5.0. Cambridge, MA:
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14. Bolumar F, Vioque J, Cayuela A. Changing mortality patterns
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H. Lifestyles factors and prostate cancer risk: a case-control
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prostate cancer: a case-control study in Ontario, Canada. Cancer
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