Over the past 40 years, people in many countries have seen huge improvements in the quality and longevity of life. A 2010 Lancet medical journal article concluded that if present trends continue, one in two children born today in affluent countries will live to celebrate his 100th birthday. This is largely because of the success these countries have had in preventing and treating chronic diseases — notably cancers, cardiovascular diseases, diabetes and chronic lung diseases.

These four diseases — known as noncommunicable diseases — are the world’s deadliest, responsible for two in three deaths. They are common diseases — we all know people who live with and die from them. But here’s something less well-known: They are widespread in developing countries, where four in five deaths from noncommunicable diseases occur.

On April 27, the world’s leading experts in health and development are meeting in Moscow for the World Health Organization Global Forum to discuss how to lead a healthy life and reverse the epidemic of noncommunicable diseases.This will be followed by a two-day First Global Ministerial Conference on Healthy Lifestyles and Noncommunicable Disease Control. Both events are critical to help all people, particularly the poor, from these diseases.

Complex factors influence the growing number of deaths from noncommunicable diseases. Aging populations and inadequate medical care are only partly to blame. The globalization of unhealthy lifestyles — in particular tobacco use, harmful alcohol consumption, bad diets and physical inactivity — plays a major role, interlinked with rapid urbanization and poverty.

Paradoxically, as people migrate to cities and gain access to more goods and services, their exposure increases to health threats like smoking and unhealthy diets. It is cheaper to buy prepared food with high salt, fat and sugar content than follow a more balanced diet of fruits and vegetables. Jobs for city dwellers are often sedentary. Transport systems and urban designs are not conducive to walking or biking, barring many from a vital strategy to prevent noncommunicable diseases: physical activity.

Industrialized countries responded decades ago to tobacco’s threat by restricting cigarette advertising and smoking in public places and increasing tobacco taxes. New York and Denmark abolished trans-fats in food products. In Britain and New Zealand, bread is now made with less salt, which reduces the risk of high blood pressure. City planners in high- and upper middle-income countries are increasing recreational spaces, pedestrian and bicycle paths. In many workplaces in the West, employees are given incentives and are awarded for following healthy lifestyles.

Yet for poor countries, giving people more options to pursue healthy choices is only a dream. A lack of resources is one reason, as are vested industry interests that oppose restrictions on their activities, even when the adverse effects on health have been clearly documented.

But governments and civil society groups, along with United Nations agencies, are today saying enough is enough. The chronic disease debate has taken center stage, turning into one of the 21st century’s greatest challenges, threatening not only health but also economic progress and overall development.

We are not starting from scratch. Collective actions by health and nonhealth players have already improved health and saved lives. The WHO Framework Convention on Tobacco Control has been ratified by more than 170 countries and is the first global health policy instrument to demand action from sectors other than health. The prevention policies needed to avert premature death and preserve employee health must permeate multiple levels of government and attract wide-based community support.

We must empower developing countries to protect their citizens, just as the governments of wealthy countries have done for theirs. It is in everybody’s interests to act, above all the world’s poorest who suffer disproportionately from communicable and now noncommunicable diseases, child and maternal health problems and other health concerns.

The numbers are stark. Of 36 million deaths a year, at least 9 million are premature and preventable, and most of these deaths occur in developing nations. The increasing burden of noncommunicable diseases forces health care costs to increase for everyone, no matter where we live. Prevention and control are keys. Failure to act is no longer acceptable.