Non-communicable diseases – The salient killer of the 21st century and beyond
Leanne M. Redman, Pennington Biomedical Research Center
As a whole, the life expectancy of the world’s population at birth has increased. In 1900, the global average life expectancy was 31 years of age, and did not exceed 50 years in even the richest countries. Now in the 21st century, the global average lifespan has surpassed more than 65 years with 80 years reported in some countries. Life expectancy is expected to increase further and many children born after 2000 will live to celebrate their hundredth birthday.
Historically, human longevity was underpinned by mortality from communicable or infectious diseases particularly those affecting children, maternal and perinatal conditions or under-nutrition. The constant progress of modern medicine and the distribution of vaccines led to the complete or near complete eradication of numerous killer diseases including small pox and polio and survival against many infectious diseases among children. What has ensued from these successes is a demographic transition in the global population with rapidly increasing numbers of middle-aged and elderly people within societies.
As life expectancy has increased, the major causes of death have shifted from childhood diseases, to non-communicable diseases (NCD) in adulthood. As a result, a different set of diseases; cardiovascular diseases, diabetes, cancers and mental illnesses, has come into prominence, all with far less impressive treatment results. For the first time in history, mortality from NCD in every world region except Africa exceeds mortality from infectious disease, perinatal and maternal conditions and under-nutrition combined.
Global modernization has bought about changes in the built environment and chronic exposure to new behavioral and societal milieus which impact the survival of people today. Tobacco and alcohol use are indeed linked to heightened risk of morbidity and mortality from NCDs however obesity serves as the most common underlying risk factor and as such the worldwide preponderance of unhealthy diets and physical inactivity derives the most attention. Multi-sectoral policies to promote healthy diets and physical activity can prevent the onset of and reduce mortality rates from many NCDs however strategies based on the prevention of lifestyle-related risk factors in adults have met with limited success. Furthermore, the capacity of health systems to respond to the growing burden of NCDs is challenged by the fact that most of the medical interventions e.g., surgery, chemotherapy, or insulin support—are expensive and not readily available to people worldwide.
Probably the most alarming concern in the current ‘obesogenic environment’ is the rise of NCD in childhood. However, given the intriguing Developmental Origins of Health and Adult Disease hypothesis which posits that optimizing nutrition during critical periods such as early in life (pre-pregnancy, pregnancy and infancy) could produce long-term changes in the structure or function of an organism and influence the life-long risk of disease, the primary prevention of NCD in adulthood may need to be a lifelong goal of the next generation.