• chronic disease
• non-communicable disease

Diseases are frequently referred to as communicable or non-communicable. Communicable diseases comprise infectious diseases such as tuberculosis and measles, while non-communicable diseases (NCDs) are mostly chronic diseases such as cardiovascular diseases, cancers, and diabetes.

Epidemics of communicable diseases follow predictable patterns, spreading across vulnerable population sectors by disease carrying agents or vectors. That leads to the term communicable. But recently many people have challenged the use of the term non-communicable and said that these diseases are actually also communicable.

How can chronic non-infectious diseases like cardiovascular diseases be communicable? The answer lies in the causation of chronic diseases. Health risk behaviours such as smoking, unbalanced nutrition, physical inactivity, and excess alcohol use are directly implicated as causal factors for chronic diseases— but the determinants of these risk taking behaviours are too frequently overlooked. These determinants should be considered as vectors for disease that are underpinned by the psycho-social, cultural, ethnic, and socioeconomic attributes of populations, society, and local communities. So the reasons why people undertake health risk behaviours need to be understood in targeting public health interventions.

Modern society promotes rapid marketing of new behaviours across populations. This is easily understood when considering marketing of fashion clothing; social “vectors” including peer groups and societal conformity are used to great effect to change behaviours.

The determinants of risk taking behaviours are also rooted in society where people seek to copy behaviours promoted as desirable (for example, access to fast food), where peer groups attract the vulnerable (for example, smoking and alcohol consumption), where society promotes certain behaviours (for example, physical inactivity), and where low socioeconomic status restricts healthy lifestyle choices.

Risk taking behaviours are in the world increasingly more prevalent in communities where levels of socioeconomic status are low with poor education, unemployment and poverty. Unhealthy behaviours as typical vectors for chronic diseases can be passed on through families, communities, and populations following demographic gradients. This in part explains the epidemic spread of obesity and diabetes across the USA during the 1990s.¹ International travellers and migrants also bring with them social vectors (for example, cooking style, hygiene practices, etc), thereby affecting both the infectious and chronic disease patterns in the host country.² In an increasingly globalised world risk behaviours are globally communicated by global marketing and global communication channels.

In established market economies, NCDs contribute around 80% of the total disease burden.³ According to the latest data, already some 60% of the deaths worldwide are due to NCDs.⁴ Arguments for improved resourcing of chronic non-communicable diseases prevention initiatives may be better received if the nature of their causation is more transparent and better understood. We advocate a shift away from the “negative” term non-communicable diseases.

The term “lifestyle related diseases” is sometimes used. The problem there is that many infectious diseases are also related to lifestyles. Furthermore, the term “lifestyle” has the connotation that individuals can easily choose their behaviours, which is often true only to a limited extent.

In many ways we feel that the most appropriate advice would be to start widely to use the conventional term “chronic diseases”. While it is accepted that infections may play a part in certain “chronic diseases” (for example, gastric ulcer and heart diseases)—and that many infectious diseases are “chronic” (for example, tuberculosis, AIDS)—we propose that the traditional term “chronic diseases” be used.

Some people prefer to add “transmissible chronic diseases”. This can highlight the concept that the social determinants of chronic diseases are usefully considered as “vectors”, promoting a more practical understanding of opportunities for targeting public health interventions that are often overlooked.