Healthcare policies and research strategies in developing countries must adapt to the new big killers, says Priya Shetty.
Threats to global health have changed. HIV/AIDS, malaria and tuberculosis were once the biggest killer diseases in the developing world — but now the world's poor are more likely to die of cancer, diabetes, and heart and respiratory diseases.
The figures are already shockingly high: worldwide, non-communicable diseases accounted for 36 million of 57 million deaths in 2008, with more than 80 per cent of these in developing countries least equipped to cope.
To draw attention to this 'epidemic' of chronic disease, the UN held a high-level summit  this week to rally action and devise new health strategies. But while this international support is essential, developing countries must lead the fight against non-communicable diseases themselves.
Experience with programmes for major infectious diseases shows they have often relied too heavily on external non-governmental agencies (NGOs) or donors, with the developing country acting as a passive partner.
Many non-communicable diseases present lifelong battles against chronic illness, rather than one-off infections, adding complexity to public health campaigns. This means that poor countries will need to devise innovative, culturally relevant prevention policies, and align their research strategies accordingly.
Surge of unhealthy behaviour
The rise of non-communicable diseases in developing countries is relatively recent. The global drive to make treatments for diseases such as HIV/AIDS and malaria more effective and easier to access has contributed to longer life expectancies, leaving people at risk of diseases that tend to develop later in life.
As poor countries have become wealthier, and their economies more open to globalisation (and aggressive product marketing), there has been a surge in unhealthy behaviour such as smoking, drinking alcohol, and eating fatty and sugary foods — all of which significantly contribute to rates of heart disease, diabetes and other conditions.
Clearly, this presents an enormous challenge to developing countries. But since any strategy to tackle this new burden must sit alongside the fight against infectious diseases, it is important to know more about the how the diseases affect people and how their prevalence is likely to grow.
Now, for the first time, the WHO has produced estimates for the mortality and prevalence of chronic diseases in each member state. For example, low- and middle-income countries account for 62 per cent of deaths from these diseases in people under 60 years of age. And in lower middle-income countries, between 1980 and 2008 this mortality rate rose to 28 per cent — more than double that in high-income countries. 
But as a recent editorial in Nature points out , it's worth looking under the surface of the alarming numbers. Demographic shifts mean that many countries have an increasingly ageing population who are more prone to non-communicable diseases — suggesting that the rise in prevalence may not fuelled by a rise in the risk of developing chronic disease.
Approaches must suit the country
With the global spotlight on non-communicable diseases, this is clearly the moment to galvanise action — but it must be 'home-grown', for several reasons.
Non-communicable diseases tend to persist for the lifetime of the person affected and so place heavy demands on ailing health systems, far more than infectious diseases. Chronic disease is unsuited to the traditional model of international aid that favours technical fixes with tangible results, such as childhood vaccines.
Donors can offer know-how to help countries bolster their health systems. But it can be hard to supply aid for diseases that need to be tackled with systemic changes in healthcare, personal behaviour and public health financing.
Moreover, tackling the behavioural risk factors for non-communicable diseases requires appropriate cultural approaches. A campaign to encourage people to quit smoking in the United Kingdom that plays on the idea of social embarrassment may be meaningless in a country with different social attitudes, such as Brazil or China.
Research and prevention needed
Developing countries will also need to re-align their research strategies so they include non-communicable diseases, even though they also benefit from clinical knowledge shared by rich countries with a longer track record in tackling them.
The well-established biotech sectors in emerging economies such as China and India are starting to make more affordable, generic versions of drugs for diabetes, cancer and heart disease.
But research is required to understand how factors such as genetic variability will influence the pattern of these diseases in poor countries. And clinical trials might also be needed to confirm that drugs that work in populations in the developed world will suit those in other countries.
Developing countries will need to encourage healthier lifestyles (with taxes on cigarettes and alcohol, for example) and make it mandatory for food products to show the nutrient breakdown. Yet without the luxury of robust health systems, countries may also need to be more active in enforcing prevention.
For instance, screening for diabetes and certain cancers is crucial for early detection, but it tends to be voluntary. But some states in India, such as Goa, have made screening for diabetes in pregnancy mandatory.
Developing countries are now taking greater ownership of their health problems, and international aid is inching its way to more equal partnerships. The need for autonomy and leadership is vital in the fight against non-communicable diseases.
Journalist Priya Shetty specialises in developing world issues including health, climate change and human rights. She writes a blog, Science Safari, on these issues. She has worked as an editor at New Scientist, The Lancet and SciDev.Net.
 United Nations high-level meeting on noncommunicable disease prevention and control
 WHO Noncommunicable diseases country profiles 2011
 Editorial Disease prioritiesNature 477, 250 (2011)