The Stagnation of the Mexican Life Expectancy in the First Decade of the Twenty

First Century: The Impact of Violent Deaths.

Vladimir Canudas-Romo* Vctor Manuel Garca-Guerrero^1

Abstract

In the first decade of the twenty first century the Mexican life expectancy changed from a

long trend of increase to stagnation. These changes concur with an increase in deaths by

homicides that the country experienced in that decade. There are 138,461 official reported

deaths by homicide in the period of 2000 to 2010. However, the time trend shows an

increase in the counts of homicides in the later years from an annual number of 10,000 to

25,000 deaths in 2010. We quantify the impact of these changes in homicides and other

causes of death in life expectancy. Male life expectancy remained around the value of 72

years from 2000 to 2010. However, the apparent stagnation in life expectancy is resultant of

increase in homicides and diabetes deaths on one hand, and the positive improvements

observed in other causes of death on the other. The negative impact of homicides is

particularly observed at ages 15 and 50, and diabetes for ages 45 and more, and they

account for almost an entire year of the male life expectancy. Mexican males would have

observed a 2 years increase in life expectancy if homicides and diabetes deaths had been

avoided.

* University of Southern Denmark, Denmark; Johns Hopkins University, USA ^ Colegio de Mexico, Mexico

Introduction

The demographic transition has been described as a period of decline from high to lower

levels of fertility and mortality (Notestein 1945, Davis 1945, Lee 2003). The mortality

aspect of this transition has been characterized by, among others, the increase in life

expectancy at birth (LE). As mortality has changed, the cause of death structure has shifted

from a dominance of deaths due to infectious diseases to a preponderance of deaths due to

chronic diseases, a change denoted as the epidemiologic transition (Omran, 1971).

As conceived initially the epidemiological transition had three stages: (a) The age of

pestilence and famine which precedes the mortality transition (LE is less than 40 years);

(b) The age of receding pandemics with steady decline in mortality and increase in LE to

levels above 40 years; and (c) The age of degenerative or human-made diseases with LE

reaching 70 years and above. Other authors have included more stages to the transition, for

example the missing component of the violent and accidental mortality (Rogers and

Hackenberg 1987).

During the second half of the twentieth century Mexico transitioned at a very rapid pace

into the second and third stages of the epidemiological transition. Life expectancy in 1950

was 49 and 45 years for females and males respectively, and changed by 2000 to 77 years

for females and 72 for males (INEGI, 2012). These changes correspond to annual increases

in life expectancy of 0.38 and 0.40 of a year for females and males respectively. These

paces of increase are far higher than the long uninterrupted increase of 0.25 per year

observed in the trend of the female record life expectancies in the world (Oeppen and

Vaupel 2002). Thus, Mexico has greatly reduced its longevity gap respect to the developed

world of countries holding the maximum life expectancy.

In the first decade of the twenty first century, Mexico experienced a dramatic change in

its public health: from 2000 to 2010 life expectancy for males stagnated and for females

experienced a modest half a year increase during the entire decade. These changes concur

with an increase in deaths by homicides that the country experienced in that decade. The

focus of the present study is to assess the contribution of violent deaths, particularly

Homicides, in explicating the observed stagnation in life expectancy.

We ask about the possible role of other causes of death in this stagnation and quantify

the changes in the age-pattern of mortality. However, our aim also has the international

perspective of comparing the Mexican situation with that of mortality shocks observed in

other countries. For example, the triple Japanese disaster of 2011,

earthquake/Tsunami/Nuclear disaster, and its devastating effect in the population of that

island nation and the well document Russian excess alcohol related mortality in the last

decades (Schkolnikov et al 2013).

The following sections include the description of the Mexican data used in the analysis,

the methods applied, results and discussion.

Data

This project uses two types of data: death counts by causes of death, and complete life

tables for the period 2000 to 2010. The information on deaths by cause of death comes

from the administrative registers managed by the National Institute of Statistics and

Geography (INEGI for its acronym in Spanish). The INEGI collects this information on an

annual basis from both the Civil Register Bureau and the Prosecutor Agencies. The first

one collects general and fetal deaths by cause, and the latter collects violent and accidental

deaths. The causes of death are according to World Health Organizations International

Classification of Diseases tenth revision (ICD-10).

Information on death counts is available by sex and single age, for each calendar year

from 2000 to 2010. Deaths in the group of Not Specified, or without age or sex, were

prorated by age and sex. We have selected to work with ten causes of death: Infectious

Diseases, Neoplasm, Diseases of the Circulatory System, Mental Disorders,

Endocrine/metabolic Diseases, Diseases of the Digestive System, Conditions of Perinatal

Period, Homicide, Other external Causes, Others causes of death not accounted by the other

groups. We further aggregate these ten causes for the years lost of life analysis explained

below.

The calculation of the age-specific death rates used in the construction of the life tables

are briefly described here (more details can be found at SOMEDE, 2011). The general

death rates are estimated from different sources: vital statistics, six different national

surveys (EMF 76-77, ENFES 87, ENADID 92, 97 and 09), three decennial censuses (1990,

2000 and 2010) and one midterm census (2005). Specific methods are applied for the

estimation of the mortality for each age group: 1) under one year old (to estimate infant

mortality rates), 2) between 1 and 4 years, and 3) for ages above 5 years.

The infant mortality rate (IMR) and the mortality rates between ages 1 and 4 come from

vital statistics, surveys pregnancy and birth histories, and census information of death

offspring and children born alive. The births in the denominator of the IMR come from

vital statistics registers. Births are underestimated (around 2%) from this data source, but

the total number of births are corrected by adding the births registered four years after the

year of occurrence (Mier y Tern in SOMEDE 2011).

The information to estimate the mortality rates for ages five and more comes from vital

registers: vital statistics and censuses. The deaths and populations are corrected for age

misspecification and smoothed. The total mid-year population from census is interpolated

using cubic splines and its age-structure is estimated with linear interpolation. Finally, the

life tables are calculated as shown in Preston, Heuveline and Guillot (2001).

We used life tables elaborated by the Ministry of Health, Labour and Welfare of Japan

to make comparable analysis as those elaborated for Mexico and the information available

on life tables for Russia from the Human Mortality database and World Health

Organization for the cause of death data.

Methods

The proportion of deaths at age x of cause i, denoted as c(x,i), was calculated and

applied to the age-specific death rates, m(x), to obtain age- and cause-specific death rates:

m(x,i)=c(x,i)m(x). These age- and cause-specific death rates were used in both the

decomposition and years lost analysis explained below.

Decomposition techniques are standard methods for comparing life expectancy across

populations and time, and analyzing the age-contributions and cause-contributions to the

differences (Preston, Heuveline and Guillot 2001). We extracted age-specific death rates,

numbers of survivors and persons-years from the life tables described above. These values,

together with the proportion of deaths for each cause in every age group, were used to

obtain the age and cause-specific death rates and contributions that make up the difference

in life expectancies between years 2000 and 2010.

We calculate the years lost due to different causes of death by focusing on the

cumulative death distribution. Let the radix of the population be equal to one, (0) = 1. At any given age x, the survival function, (), and the function of the distribution of deaths from 0 to the given age x, (0, ), together add to the radix of the population:

() + (0, ) = 1, (1)

The function of the distribution of deaths can be further substituted for the addition of

the deaths by the different causes of death, (0, , ). If there are n mutually exclusive causes of death equation (1) can be re-written as:

() + (0, , )=1 = 1. (2)

Integrating both sides from 0 to an age of interest a, returns a relation of the total

number of possible years lived between zero and age a, namely a, and the temporary life

expectancy between ages 0 and a, and years lost due to each of the causes of death:

()0 + (0, , )0=1 = . (3)

or with more succinct notation as,

0 + 0=1 = , (4)

where temporary life expectancy is defined as 0 = ()0 and the years lost to each cause of death as 0 = (0, , )0 . More details on this method can be found in Andersen, Canudas-Romo and Keiding (2013).

Results

Age-specific death rates

Figure 1 presents the age-specific death rates for Mexican females and males in 2000

and 2010. In the most recent year the accident hump characteristic of the age-group 18-25

increases for females and males. Although, for males the increase in the risk of death is

observed up to age 40. For the rest of the ages there is, apparently, little change except for

the slight decline in lowest death rates for males around age 10 to 12.

[Figure 1 about here]

Cause-decomposition analysis

The female and male age-contribution to the change in the Mexican life expectancy

between 2000 and 2010 are observed in Figures 2A and 2B respectively. Between 2000 and

2010 there was barely any increase in the average life span for females, changing from 77.2

to 77.8 years. But the situation is far worse for their male counterparts which experienced

no change in life expectancy remaining at 72 years. In Figures 2A and 2B bars above the

horizontal line at the value of zero show the contribution of age groups to the increase in

life expectancy while those below oppose this change. The progress made in bringing down

mortality in the first year of life is equivalent to more than 0.4 of a year of the life

expectancy change both for females and males. Other age-groups that experienced

survivorship increases were the ages 45 to 70 for males and ages 30 to 75 for females.

However, young adults and those above 75 have observed increases in mortality that

translate into this negative contributions.

[Figure 2A and 2B about here]

This contrast for example with the situation observed during the triple disaster of 2011

in Japan where at every single age deterioration in mortality was experienced. The female

and male age-contribution to the change in the Japanese life expectancy between 2010 and

2011 are observed in Figures 3A and 3B respectively. Between such years there was a

decrease in the average life span for females, changing from 86.4 to 85.9 years. Similarly,

there was a decrease in the average life span for males, changing from 79.6 to 79.4 years. In

Figure 3A all bars are below zero which means that all age groups contributed, more or less

in the same magnitude (except the age-group of 95 and more), to the decrease in female life

expectancy at birth. Similar results are observed for Japanese males, except for those aged

group 0-1, 45-49 and 55-65.

[Figure 3A and 3B about here]

The female and male age and cause-specific contributions to the change in the Mexican

life expectancy between 2000 and 2010 are observed in Figures 4A and 4B respectively.

Between 2000 and 2010 the main cause of female LE increase was the improvement of

perinatal periods conditions, concentrated in the first year of life. Its contribution was of

0.26 of a year. Advances in the prevention of both diseases of the circulatory system and

neoplasm between ages 35 to 85, contributed increasing LE in 0.18 and 0.19 of a year

respectively. As a counterpart, endocrine/metabolic diseases, predominantly diabetes,

(concentrated in ages of 40 and more) and homicides (concentrated in ages between 15 and

35 years) contributed in a negative way to LE.

Similarly, the main cause of the increase in the male LE also was the reduction in

perinatal deaths, concentrated at ages below one. Its contribution was of 0.28 of a year.

Advances in preventing both diseases of the digestive systems and other external causes,

between ages 25 to 70 and 40-80 respectively, contributed combined to an increase in LE of

0.4 of a year. Nevertheless, homicides (concentrated in ages between 15 and 55 years) and

endocrine/metabolic diseases, where most of the cases are diabetes, (concentrated in ages of

30 and more) contributed in a negative way to LE. Homicides alone reduced LE in 0.6 of a

year. Similar to the increase in LE gained against perinatal, diseases of digestive system

and other external causes together.

[Figure 4A and 4B about here]

Years lost analysis

Figure 5 presents the survival function for the Mexican population in 2005 for females

and males, as well as the death accumulation by age and cause of death, or years lost by

causes of death. The causes of death have been further grouped to more clearly see their

trend into external (homicide, suicide and accidents), cardiovascular diseases or CVD,

cancers, diabetes, perinatal, and a group of remaining causes not accounted by the other

five. After age 55 the rapid increasing trend of CVD, cancers and diabetes mortality is

observed in the spread of these colored bands. While for females external causes have a

moderate presence by age 55, for males this cause is among the most important components

of years lost of life.

.

[Figure 5 about here]

To put this high numbers of violent deaths (or external causes) in context with other

situation of excess mortality, we contrast the Mexican male results with the same analysis

for their Russian counterparts. Table 1 presents the years lost to external causes,

cardiovascular diseases, cancers and other causes. By age 55, 70 and 85 a total number of

2.9, 6.5 and 14.3 years respectively have been lost in the Mexican male life table. The

numbers for Russian males are 5.9, 13.9 and 26.4 years for the three mentioned ages. Over

age, the years lost to external causes in Mexico reduced from representing 20% to 15% of

all deaths, while in Russia the reduction is from 34% to 31%.

[Table 1 about here]

Discussion

The impact of catastrophic events in the health of a population is captured without

ambiguity in the changes in mortality, or as studied here changes in life expectancy. The

influences of these types of shocks in mortality depend on its intensity, durability, and the

population context where they occur. Japans triple disaster was intense, but its duration

was short and the public health context is far better than for many other countries in the

world. The population of Japan is of 127 million habitants, around 20,000 deaths occurred

during the disaster of 2011, equivalent to a decline in life expectancy of half a year for

females. As such, Japan remains as the country with the highest life expectancy in the

world (Canudas-Romo & Dokko, 2010). Russia on the other hand has had a long and

lasting excess mortality, which is now reducing after more than a decade of high levels

(Schkolnikov et al 2013).

Mexico, with 112 millions habitants, has had a total of 138,461 official deaths by

homicides in the period 2000 to 2010 and alone in 2009 and 2010 above 20,000 homicides

per year. The intensity and severity of this catastrophic event has increased over time, and

its duration although there was a clear beginning its end is unpredictable, and there are no

signs that violence is slowing down. At the turn of the century Mexico was equipped with a

good medical and public health system; institutions that brought the country to life

expectancies levels of 77 years for women and 72 for men in the year of 2000. These values

are higher than the mean life expectancies for eastern European countries of 76 and 67

years for females and males respectively (own calculations from HMD).

In 2000, Mexico stood at a critical moment of development with favorable demographic

dividend, or having its biggest proportion of persons between ages 15 to 65 in history.

Around 2000 the proportion of persons in the age-group 15 to 65 passed the 60% mark

respect to the total population and by 2010 it had reached 64%. As a consequence, the total

dependency ratio decreased from 76 dependents per every 100 workers 15-64, to 56

dependents by 2010. Furthermore, in recent population projections Garca-Guerrero (in

press) has shown that this decrease could continue until mid-2030s. We had hypothesized

that violent deaths have had a severe impact in terms of loss time of the window of the

Mexican demography dividend. However, its toll on this respect is not numerically evident

and it stands at much better situation than other countries that are also confronting health

crises as Russia.

The lack of opportunities for young people (employment, education, etc.), added to the

great social disparity among socioeconomic status, have catalyzed the current crisis in the

country. On top of that, at the end of twentieth century the main drug-cartels in the country

were disbanded and those who remained started a strong fight for territories. The drug

cartels have a deep connection with the Mexican civilian population, so the States war

against the cartels has directly and indirectly affected the Mexican population. This war

was intensified during the government 2006-2012. In 2012 Mexicans elected a president

from a different party than for the last twelve years. Would the direction of the current

violence change in the coming years with the new leadership of the country? Answering

this question is beyond the scope of this research. Furthermore, our quantification of

violence only shows the extreme result of the development in the latest years, namely its

deaths, but the social, psychological and physical scars that violence has left in the country

are not possible to quantify in such simplistic ways.

References

Andersen, P.K., Canudas-Romo V. and N. Keiding. 2013. Cause-specific measures of life

years lost. (Available from the authors).

Bennet, N.G. and S. Horiuchi. 1981. Estimating the completeness of death registration in a

closed population. Population Index 47(2):207-221.

Bennet, N.G. and S. Horiuchi. 1984. Mortality estimation from registered deaths in less

developed countries. Demography 21(2):217-233.

Canudas-Romo, V. and I. Dokko. 2010. The Contenders of the Future Record Life

Expectancy: The Widening Gap to Japan. European Population Conference 2010,

Vienna, Austria.

Davis, K. 1945. "The World Demographic Transition." Annals of the American Academy of

Political and Social Science 237: 1-11.

Garca-Guerrero, V. M. (in press). The Population Projections of Mexico, in C. Rabell

(coord.) The Population of Mexico, 2nd Ed., Fondo de Cultura Econmica, Mxico.

INEGI, Mexican National Institute of Statistics and Geography. 2012. (accessed October,

2012). http://www.inegi.org.mx/

Lee, R. 2003. The Demographic Transition: Three Centuries of Fundamental Change.

The Journal of Economic Perspectives 17(4):167-190.

Ministry of Health, Labour and Welfare, Tokyo, Japan. Available at:

http://www.mhlw.go.jp/english/database/

Notestein, FW. 1945. "Population The Long View." In: Schultz, T.W. (ed.), Food for

the World. Chicago: University of Chicago Press.

Omran, A. 1971. The Epidemiological Transition. Milbank Memorial Fund Quarterly 49:

509-38.

Oeppen, J. and J.W. Vaupel. 2002. Broken Limits to Life Expectancy. Science 296:

1029-1031.

Preston, S., P. Heuveline and M. Guillot. 2001. Demography. Measuring and Modeling

Population Processes. Blackwell Press.

Rogers, R.G. and R. Hackenberg. 1987. Extending epidemiologic transition theory.

Social Biology 34: 234-243.

Shkolnikov, V; Andreev, E; McKee, M; Leon, D (2013) Components and possible

determinants of the decrease in Russian mortality in 2004-2010. Demographic Research,

28 (32). pp. 917-950.

SOMEDE, Mexican Society of Demography (2011). Demographic estimates for Mexico

and its States, 1990-2010, CONAPO, unpublished.

Table 1. Years lost of life for Mexican and Russian males in 2005 by selected ages.

Mexico

Age, X X-LifeExp(0-X) Cancer CVD External Other Sum 55 2.9 0.1 0.1 0.5 2.2 2.9 70 6.5 0.4 0.3 1.1 4.6 6.5 85 14.3 0.9 1.1 2.3 10.0 14.3

Russia Age, X X-LifeExp(0-X) Cancer CVD External Other Sum

55 5.9 0.2 0.6 2.0 3.1 5.9 70 13.9 0.7 2.0 4.4 6.8 13.9 85 26.4 1.4 4.4 8.1 12.5 26.4 Source: INEGI, SSM, HMD & WHO

0 20 40 60 80 100

1e0

41e

03

1e0

21e

01

1e+0

0

Age

Dea

th ra

tes

(log

scale

)Figure 1. Agespecific death rates, Mexico 2000 and 2010.

Female 2000Female 2010

Male 2000Male 2010

014

59

101

4

151

9

202

4

252

9

303

4

353

9

404

4

454

9

505

4

555

9

606

4

656

9

707

4

757

9

808

4

858

9

909

4

95+

Ages

Cont

ributio

n to

Life

Exp

ecta

ncy

Gap

0.2

0.0

0.2

0.4

0.6

Figure 2A. Agecontribution to the 0.59 years of difference in Mexican female life expectanciesbetween 2000 (LE=77.2) and 2010 (LE=77.79). Mortality that contributed with the

increase accounted for 0.72 of a year and that with the decrement 0.13.

014

59

101

4

151

9

202

4

252

9

303

4

353

9

404

4

454

9

505

4

555

9

606

4

656

9

707

4

757

9

808

4

858

9

909

4

95+

Ages

Cont

ributio

n to

Life

Exp

ecta

ncy

Gap

0.2

0.0

0.2

0.4

0.6

Figure 2B. Agecontribution to the 0.07 years of difference in Mexican male life expectanciesbetween 2000 (LE=71.97) and 2010 (LE=72.04). Mortality that contributed with the

increase accounted for 0.7 of a year and that with the decrement 0.63.

014

59

101

4

151

9

202

4

252

9

303

4

353

9

404

4

454

9

505

4

555

9

606

4

656

9

707

4

757

9

808

4

858

9

909

4

95+

Ages

Cont

ributio

n to

Life

Exp

ecta

ncy

Gap

0.2

0.0

0.2

0.4

0.6

Figure 3A. Agecontribution to the 0.48 years of difference in Japanese female life expectanciesbetween 2010 (LE=86.38) and 2011 (LE=85.9). Mortality that contributed with the

increase accounted for 0 of a year and that with the decrement 0.49.

014

59

101

4

151

9

202

4

252

9

303

4

353

9

404

4

454

9

505

4

555

9

606

4

656

9

707

4

757

9

808

4

858

9

909

4

95+

Ages

Cont

ributio

n to

Life

Exp

ecta

ncy

Gap

0.2

0.0

0.2

0.4

0.6

Figure 3B. Agecontribution to the 0.2 years of difference in Japanese male life expectanciesbetween 2010 (LE=79.63) and 2011 (LE=79.43). Mortality that contributed with the

increase accounted for 0.04 of a year and that with the decrement 0.23.

0.2

0

0.2

0.4

0.6

0 14 59 101415192024252930343539404445495054555960646569707475798084 85+Ages

Cont

ributio

n to

Life

Exp

ecta

ncy

Gap

Figure 4A. Age and causecontribution to the 0.59 years of difference in female life expectancy between 2000 (LE=77.2) and 2010 (LE=77.79) in Mexico.

Infectious Diseases 0.16Neoplasm 0.19Diseases of the Circulatory System 0.181Mental Disorders 0.007Endocrine/metabolic Diseases 0.209Diseases of the Digestive System 0.003Conditions of Perinatal Period 0.261Homicide 0.046Other external Causes 0.03Others 0.031

Source: INEGI & CONAPO

0.2

0

0.2

0.4

0.6

0 14 59 101415192024252930343539404445495054555960646569707475798084 85+Ages

Cont

ributio

n to

Life

Exp

ecta

ncy

Gap

Figure 4B. Age and causecontribution to the 0.07 years of difference in male life expectancy between 2000 (LE=71.97) and 2010 (LE=72.04) in Mexico.

Infectious Diseases 0.196Neoplasm 0.1Diseases of the Circulatory System 0.088Mental Disorders 0.134Endocrine/metabolic Diseases 0.395Diseases of the Digestive System 0.219Conditions of Perinatal Period 0.279Homicide 0.599Other external Causes 0.198Others 0.021

Source: INEGI & CONAPO

0 20 40 60 80

0.0

0.2

0.4

0.6

0.8

1.0

Ages

Prob

abilit

y of

Sur

vivi

ng

ExternalOthersPerinatalDiabetesCVDCancer

Figure 5.Life table distribution of survivors and deaths by cause of death,for females from Mexico in year 2005

Source: INEGI, SSM.

8555 70

0 20 40 60 80

0.0

0.2

0.4

0.6

0.8

1.0

Ages

Prob

abilit

y of

Sur

vivi

ng

ExternalOthersPerinatalDiabetesCVDCancer

Figure 5. Life table distribution of survivors and deaths by cause of death,for males from Mexico in year 2005

Source: INEGI, SSM.

8555 70

The Stagnation of the Mexican Life Expectancy in the First Decade of the Twenty First Century: The Impact of Violent Deaths.AbstractIntroductionDataMethodsResultsDiscussionReferences

Figure5.pdfFig1Mex2000bFFig1Mex2000bMFig1Mex2005bFFig1Mex2005bMFig1Mex2010bFFig1Mex2010bM