(August 2012) Noncommunicable diseases (NCDs) such as heart disease,
cancer, diabetes, and lung disease are no longer only a problem
for wealthy countries. These former “diseases of affluence”
are now the leading causes of death in all the world’s regions
except sub-Saharan Africa (WHO 2011a). And NCDs kill
people earlier in poorer countries: The toll NCDs are taking
(measured by years of life lost) on people ages 60 and older in
low- and middle-income countries is much greater than for
people in high-income countries.

The National Institute on Aging (NIA) supports a variety
of research on the patterns and dynamics of NCDs among
older adults in low- and middle-income countries. This newsletter
highlights some of the recent research by NIA-supported
investigators and others that can inform policies
and programs to prevent, delay, and treat NCDs.

Epidemiological Context

NCDs, also known as chronic diseases, do not pass from
person to person, in contrast to infectious diseases. Chronic
diseases are of long duration and generally progress slowly
(WHO 2011a). The most common NCDs are cardiovascular
diseases (including heart disease and stroke), diabetes,
cancer, and chronic respiratory diseases (including chronic
obstructive pulmonary disease and asthma). The most
important modifiable risk factors for NCDs are unhealthy
diet, physical inactivity, tobacco use, and excessive alcohol
consumption. These factors may all be affected by lifestyle
choices that are often influenced by economic development
and urban living.

A number of interrelated trends have led to the growing
burden of NCDs in low- and middle-income countries.
These include a decline in the share of deaths from infectious
disease due to improvements in nutrition, public health, and
medicine; longer life expectancies as more children survive
into adulthood; and population aging, as women have fewer
children and older people represent a greater proportion of
the total population. This shift in disease patterns is characterized
by a decline in deaths from infectious diseases of
childhood and an increase in NCDs of adulthood, known as the epidemiological transition. These changes reflect advances
in socioeconomic development and progress in battling the
most virulent infectious diseases. But the unprecedented pace
of population aging is helping to fuel the growing burden of
NCDs in low- and middle-income countries: While high-income
countries such as France and Sweden had 100 years to
adjust as the proportion of older adults doubled from 7 percent
to 14 percent, countries such as China, Brazil, and
Thailand have experienced that shift in less than one quarter
the time (Kinsella and He 2009). The challenges facing low-resource
countries confronting demographic and epidemiological
transitions is great, and the data needed to make important
decisions is only now becoming available.

Disease Patterns

The prevalence of chronic disease and the biological markers
that often precede disease (such as high blood pressure and
obesity) vary widely among and within countries. Higher education and income levels have been associated
with better health and longer lives in high-income
countries, but researchers are finding different patterns in low- and middle-income countries. Monteverde and colleagues
(2010) examined the impact of education levels on
deaths related to being obese or overweight among individuals
ages 60 and older in Mexico and the United States, using
data from the Mexican Health and Aging Study and the U.S.
Health and Retirement Survey. They found a much stronger
connection between the likelihood of death and lower levels
of education in the United States than they did in Mexico.

Researchers in India found a pattern opposite from that seen
in the broader population in high-income countries. Using
pilot data from the Longitudinal Aging Study in India (LASI),
Lee and colleagues (forthcoming) found an association
between higher socioeconomic status (SES) and increased risk
of hypertension among older Indians. Overall, they found
twice the risk of cardiac conditions for older Indians who had
higher education levels compared with their less-educated
counterparts. Similarly, analysis of a comprehensive survey of
Costa Ricans ages 60 and older showed that the prevalence of
hypertension and obesity and the likelihood of NCD-related
deaths were greatest among better-educated and wealthier
individuals (Rosero-Bixby and Dow 2009). These researchers
suggest that behaviors associated with urban living and economic
development—including sedentary lifestyles and high-fat
and high-calorie diets—may blunt or erase the health
advantages conferred by education and income in low- and
middle-countries. A comparison of results from identical analyses
using data from Taiwan, Costa Rica, and the United
States also challenges “the commonly held assumption that
more educated individuals have healthier biological profiles
than their less educated peers” (Goldman et al. 2010). Among
older adults in Taiwan and Costa Rica, biological markers for
chronic diseases such as diabetes, hypertension, and cardiovascular
disease do not help explain differences in self-rated health
and functional limitations.

Poor conditions suffered early in life may also affect patterns
of NCDs among older adults in low- and middle-income
countries. A review of studies that examined associations
between early life conditions and older adult health (in
Brazil, China, Costa Rica, Mexico, and Puerto Rico and in
major cities in Latin American and the Caribbean) suggests
that early life environment plays an important role in adult
health (McEniry, forthcoming). While the exact mechanisms
have not been identified, the authors found several strong
associations between:

  • In utero and early infancy exposure to poor nutrition and
    infectious diseases (independent of other early life and
    adult conditions) and adult heart disease and diabetes.
  • Poor nutrition during childhood and difficulties in adult
    cognition and diabetes.
  • Specific childhood illnesses such as rheumatic fever and
    malaria and adult heart disease and adult mortality.
  • Poor childhood health and adult chronic diseases, functional
    limitations, and diabetes.
  • Poor childhood SES and adult mortality, functional limitations,
    disability, and cognition.
  • Parental survival during childhood and adult cognition,
    disability, and functional limitations.

Specifically, among rural-born older adults in Puerto Rico, the
probability of developing heart disease was 65 percent higher
for those who experienced seasonal malnutrition in utero than
for their counterparts born during or soon after harvest
(McEniry and Palloni 2010). In urban Latin America,
researchers found strong links between malnutrition in early
childhood and self-reported diabetes in older adults (Palloni et
al. 2006). In China, individuals who rarely or never suffered
from a serious illness during childhood and those who
received adequate medical care during illness had significantly
lower likelihoods of suffering cognitive impairment, disability,
or poor health at ages 80 and older (Zeng, Gu, and Land
2007). These researchers argue that the impact of poor early
life conditions may be contributing to rapid increases in
NCDs in low- and middle-income countries.

Risk Factors

The social and economic transitions that take place as countries
go through the process of economic development may
explain some of the differences between the patterns of mortality
and morbidity seen in low- and middle-income countries
and the patterns observed in high-income countries.
For example, a comparison of NCD-related disability levels
among older adults in Mexico and the United States found
lower levels of disability in Mexico than in the United States
(Wong et al. 2011). These difference may reflect the fact
that compared with older adults in high-income countries,
older adults in low- and middle-income countries are more
likely to have had lower levels of exposure to NCD-risk factors
associated with urban living (such as smoking, sedentary
lifestyles, and processed foods).

The challenge for middle- and low-income countries is to
minimize or avoid the negative impact of lifestyle changes
that accompany modernization and urbanization. There is
evidence that countries may go through a “lifestyle transition,”
as people adopt and then later abandon unhealthy
behaviors, with richer and better-educated people at the forefront
of the changes (Wong et al. 2008). In Mexico, more-educated
older adults were more likely to smoke than older
adults with less education, but the opposite pattern was true
in the United States. The United States used to have a higher
prevalence of smoking among older adults but is in the process
of a transition away from smoking, whereas Mexicans
have not started the transition away from this unhealthy
behavior. Researchers have also found evidence of declining
obesity levels and increasing physical activity among older
adults in the United States but not in Mexico.

In the wake of economic development and urbanization in
low- and middle-income countries, NCDs may become concentrated
among people with lower education and income
levels (Fleischer, Roux, and Hubbard 2011). Researchers analyzed
older adult populations in 70 low- and middle-income
countries and found a trend toward increasing markers of
NCDs among people of lower SES as countries became more
urban. Specifically, in the least urban countries, adults with
higher education levels were more likely to be overweight or
obese while the opposite was true in the most urban countries,
particularly among women.

Health Care

The volume and complexity of ongoing health care needs of
older adults with NCDs will challenge the health care systems
of low- and middle-income countries. These health systems
have been more focused on treating infectious disease,
and the prolonged nature of NCDs will likely increase health
care costs. In addition to the costs of treating NCDs themselves,
there are also health care costs resulting from conditions
associated with NCDs. Evidence indicates that NCDs
play a major role in the rapid physical declines that contribute
to disability levels in low- and middle-income countries
(Sousa et al. 2009; and Chiu, Wray, and Ofstedal 2011).

How do low- and middle-income countries address the
health care needs of older people, including those who already
show signs of NCD-related health problems? Providing older
people with access to affordable health services has been effective
in some settings. In Taiwan, the introduction of national
health insurance led to an increase in the proportion of older
adults with hypertension who sought medical care and/or
took medication for their condition (Prakash and Ofstedal
2010). In Mexico, the introduction of an income support program
aimed at poverty alleviation among the elderly ages 70 and older led to an increase in the number of doctor visits
and the amount of medicine purchased (Aguila et al. 2011).

According to WHO, low- and middle-income countries do
not appear to be successfully treating people with even the
most common risk factor for NCDs—high blood pressure
(WHO 2012). While the share of older people with high
blood pressure ranged from 32 percent to 78 percent in the
six countries tracked in the Study on Global Ageing and
Adult Health, only between 4 percent to
14 percent were receiving effective treatment.
Evidence from a WHO analysis suggests that providing
multi-drug therapy for those at high risk of cardiovascular
disease is extremely cost-effective at less than US$1 per person
a year in low-income countries (WHO 2011b). However,
identifying at-risk individuals is no easy task: Despite a
national program in hypertension detection and education,
one out of four older Costa Ricans were unaware that they
had high blood pressure (Méndez-Chacón, Santamaría-Ulloa,
and Rosero-Bixby 2008). Given that rising levels of NCDs
will take a heavy toll not only on human health and well-being
but also on economic growth and development, Bloom
and colleagues (2012) urge governments, civil society, and the
private sector to commit to combating these diseases.


Paola Scommegna is a senior writer/editor at the Population Reference Bureau.


References

Please refer to PDF of report.

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