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What's killing us? For decades, global health leaders have focused on diseases that can spread — AIDS, tuberculosis, new flu bugs. They pushed for vaccines, better treatments and other ways to control germs that were only a plane ride away from seeding outbreaks anywhere in the world.

Now they are turning to a new set of culprits causing what United Nations Secretary-General Ban Ki-moon calls "a public health emergency in slow motion." This time, germs aren't the target:

We are, along with our bad habits like smoking, overeating and too little exercise.

Next week, the U.N. General Assembly will hold its first summit on chronic diseases — cancer, diabetes and heart and lung disease. Those account for nearly two-thirds of deaths worldwide, or about 36 million. In the United States, they kill nearly 9 out of 10 people. They have common risk factors, such as smoking and sedentary lifestyles, and many are preventable.

It's hard to fathom the suffering these maladies are causing in some parts of the world.

For example, until a few years ago Ethiopia had one cancer specialist, Dr. Bogale Solomon, for more than 80 million people.

"Now three more oncologists have joined," he said, and these four doctors struggle to treat patients in a country where cancer drugs and even painkillers are in short supply.

Wondu Bekele took his 2-year-old son, Mathiwos, to that lone cancer center in Addis Ababa when the boy developed leukemia. The desperate father got advice from St. Jude Children's Research Hospital in the United States, procured chemotherapy drugs from India, and against all odds, got his son treated. Yet the little boy died because the hospital had no separate ward to protect him from catching disease from other patients. The father founded a cancer society in his son's name and will represent cancer groups at the U.N. meeting.

"Practically all cancer-related medicines are either nonexistent or beyond the reach of ordinary Ethiopians," he said. "We are struggling to make a difference here."

Advocates may be struggling to make a difference at the U.N., too. Key officials have been unable to agree before the meeting on specific goals — reducing certain diseases or risk factors such as smoking by a specific amount and date. With the global economy in turmoil, finding money to meet any goals could be an even bigger hurdle.

"The timing is difficult with the economy the way it is, but it should not prevent us from setting goals," said Dr. Sidney Smith, who heads the World Heart Federation, an umbrella group of more than 200 organizations focused on heart disease.

"Many of the things we're proposing cost very little" and some, such as smoking cessation, even save money, said Smith, a cardiologist at the University of North Carolina at Chapel Hill. "We're not talking about trying to find a new magic bullet. We're just talking about behavior and cost-effective medicines" like aspirin and generic blood pressure drugs that lower the risk of multiple diseases, he said.

This is only the second time the U.N. has taken up a health issue. The previous one in 2001 led to creation of the Global Fund to Fight AIDS, Tuberculosis and Malaria, with billions from governments and private groups such as the Bill & Melinda Gates Foundation.

Now even rich nations are cash-strapped, and it's unclear whether private groups will step in.

Asked whether the U.N. meeting would alter its focus, the Gates Foundation indicated it would not.

"Unfortunately, there is a lack of comparable investment in infectious diseases, which disproportionately affect the world's poorest," said a statement from the foundation. "Our priority will continue to be investing in cost-effective treatments that lead to maximum impact and fill in a gap where other resources are not invested."

However, advocates say there are disparities in chronic diseases, too.

"The common belief that cancer is a problem of rich countries is a misconception," said Dr. Eduardo Cazap, president of the Union For International Cancer Control.

Dr. Ala Alwan, assistant director-general of the World Health Organization, agreed.

"Most countries in Africa are currently overwhelmed with their increasing demand" from cancer patients, and the region also has the highest rates of stroke and high blood pressure in the world, Alwan said.

In Ghana, 23 million people are served by two oncology centers; the country has four cancer doctors and no specialist cancer nurses, said Dr. Allen Lichter, CEO of the American Society of Clinical Oncology, an organization of cancer specialists. The society has trained more than 2,000 doctors in developing countries on cancer care and plans to do more.

Africa also remains the only region in the world where infectious diseases, maternal-infant health problems and poor nutrition still kill more people than noncommunicable diseases do.

Worldwide, stroke and heart-related diseases account for nearly half of all noninfectious disease deaths — 17 million in 2008 alone, WHO says. Next is cancer (7.6 million deaths), followed by respiratory diseases such as emphysema (4.2 million). Diabetes caused 1.3 million deaths in 2008, but that's misleading — most diabetics die of cardiovascular causes.

The U.N. chose to focus on those four diseases and their common risk factors: tobacco use, alcohol abuse, unhealthy diets, physical inactivity and environmental carcinogens.

They have varied impact around the world:
—Europe and North America. These regions are paying the price of too much eating, too little exercise and smoking: heart disease and diabetes dominate. Cancers that are more prevalent with age — breast and prostate — reflect long life spans in these regions where treatment is widely available. In Eastern Europe and the former Soviet Union, lung cancer is the dominant cancer in men. Europe has the highest smoking prevalence in the world: 29 percent.

—Asia. Southeast Asia has the lowest rates of obesity in the world, even lower than Africa. Yet in China, where only 6 percent of the population is obese, nearly 4 in 10 people have high blood pressure. China also has three times the death rate from respiratory diseases as the United States. Many areas also have high rates of infection with HPV, a sexually spread virus that can cause cervical cancer.

In India, the government has launched an aggressive diabetes and high blood pressure screening project. There are 51 million diabetics in India, the second-highest incidence in the world after China. Lung cancer is the most common type of cancer in India among men; in women, it's cervical cancer.

—Central and South America. Cancer prevalence patterns largely resemble North America except that cervical cancer dominates among women in certain areas. Access to care is much poorer in many countries. Dr. Angel Sanchez, an International Cancer Corps volunteer for the American Society of Clinical Oncology, told of conditions at a hospital in Honduras, where there are more than 700 new cancer cases every year for two oncologists to handle.

John Seffrin, CEO of the American Cancer Society, said the U.N. session must lead to specific goals and more money, or a chance to make a difference with these diseases may be lost for decades.

"This is our moment in the sun," he said. "A resolution alone is insufficient."