(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.


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