Contribution of six risk factors to achieving the 25x25 non-communicable disease mortality reduction target

Summary of study¹

Location: Global

What we know:  Non-communicable diseases (NCDs) cause more than 35 million deaths every year and account for more than half of the deaths in every region except sub-Saharan Africa. 

What this article adds: Nine global targets have been set to reduce premature mortality from four NCDs by 25% by 2025 (25x25). A recent analysis estimates that if risk factor targets are achieved, the probability of dying from the four main NCDs between the ages of 30 and 70 years will decrease by 22% in men and by 19% in women between 2010 and 2025 and delay or prevent more than 37 million deaths. Most of the benefits will be in low and middle income countries. Further analyses are needed to assess benefits by region and country and implementation of effective policies and programmes to reduce these risks.

Non-communicable diseases (NCDs) cause more than 35 million deaths every year and account for more than half of the deaths in every region except sub-Saharan Africa. In 2011, the UN General Assembly adopted a political declaration that committed member states to the prevention and control of NCDs.  Subsequently, countries agreed to adopt nine global targets, including an overarching target of reducing premature mortality from the four main NCDS (cardiovascular diseases, chronic respiratory diseases, cancers and diabetes) by 25% relative to their 2010 levels, by 2025 (referred to as the 25x25 target). Countries also agreed on targets for selected NCD risk factors: tobacco use, harmful alcohol use, salt intake, obesity, raised blood pressure, raised blood glucose, diabetes and physical inactivity. Two additional targets focus on treating people at high risk of heart attack and stroke, and on the availability of drugs to treat NCDs.

The risk factors and mortality targets were chosen independently, based largely on the experiences of countries that had been successful in reducing each of them. To plan and prioritise NCD control and prevention strategies, it is important to know how much achieving the risk factor targets would contribute towards reducing NCD mortality and whether additional actions are needed to achieve the 25x25 target. A recently published study therefore analysed the potential impacts of reducing six preventable risk factors on future trends in NCD mortality, in aggregate and by disease for high-income, low-income and middle-income countries.

The study estimated the impact of achieving the targets for tobacco and alcohol use, salt intake, obesity and raised blood pressure and glucose on mortality between 2010 and 2025. The method accounted for multi-causality of NCDs and for the fact that when risk factor exposure increases or decreases, the harmful or beneficial effects on NCDs accumulate gradually. Data used for risk factor and mortality trends were from systematic analyses of available country data. Relative risks for the effects of individual and multiple risks, and for change in risk after decreases or increases in exposure, were from re-analyses and meta-analyses of epidemiological studies. 

Key findings 

If risk factor targets are achieved, the probability of dying from the four main NCDs between the ages of 30 and 70 years will decrease by 22% in men and by 19% in women between 2010 and 2025, compared with a decrease of 11% in men and 10% in women based on current trends with no additional action. Achieving the risk factor targets will delay or prevent more than 37 million deaths (16 million in people aged 30-69 years and 21 million in people aged 70 years or older) from the main NCDs over these 15 years compared with a situation of rising or stagnating risk factor trends. Most of the benefits of achieving the risk factor targets, including 31 million of the delayed or prevented deaths, will be in low and middle-income countries (LMIC), and will help to reduce the global inequality in premature NCD mortality. A more ambitious target on tobacco use (a 50% reduction) will almost reach the target in men (>24% reduction in the probability of death) and enhance the benefits to a 20% reduction in women. 

This type of population-level analysis has limitations. First, as with all estimations of future trends, unexpected factors, (e.g. new highly effective prevention and treatment interventions or macro-economic shocks) can substantially modify trends in risk factors or mortality. Second, despite improvements in epidemiological surveillance, risk factor exposures and deaths in some countries and regions are affected by data shortage and have relied on prediction models. Third, the relative risks (RRs) used in this study were from observational studies, and thus could have been affected by residual confounding. Fourth, the epidemiological studies that informed the RRs were done in largely western and Asian populations. Fifth, the researchers did not analyse physical inactivity because how much of its effects are mediated through obesity, raised blood pressure and glucose has not been quantified, and because there are no consistent data for time trends. Similarly, the researchers did not analyse other forms of tobacco use because of the relative scarcity of data for exposure, which could have led to underestimates of the benefits of reduced exposure for some cancers in south Asia, where oral tobacco use is common. 

At present, tobacco use is the most policy-responsive of targeted risk factors with major successes in tobacco control in many countries. Alcohol consumption has decreased in in some high-income countries but remains a major public health burden in Eastern Europe, Latin America and sub-Saharan Africa. Reducing the harmful use of alcohol in these regions, and preventing its rise in Asia and elsewhere, should be a priority, and can be achieved by use of policies that limit access, increase prices and restrict or ban advertising. Lower dietary salt and better diagnosis and treatment have contributed to reducing blood pressure in some high-income countries. Locally applicable salt reduction or substitution strategies are urgently needed in LMICs, where salt intake remains high. Higher coverage of blood pressure treatment will need strengthening of the primary care system and the development and implementation of guidelines for use by primary care personnel. 

The researchers suggest that these findings demonstrate that further analyses are now needed to assess the benefits of achieving risk factor targets in each region and country, and importantly, by implementing effective policies and programmes to reduce these risks. An integrated approach will not only reduce NCD mortality by 2025, but will also help sustain this reduction beyond 2025. Such integration will also be essential to efforts to make NCD reduction a part of the post-2015 development agenda and to efforts to achieve a grand convergence in health across the world by 2035.

¹ Kontis. V et al (2014). Contribution of six risk factors to achieving the 25x25 non-communicable disease mortality reduction target: a modelling study. The Lancet, vol 384, August 2014, pp 427-436