NEW YORK – Millions of deaths from chronic illness and up to one-third from heart disease could be avoided or postponed if developing nations increased their health budgets by about 4 percent to put basic prevention measures in place.

The package — which includes tobacco control, reduction of salt and fat in processed food, basic generic drugs for heart patients, screening for cervical cancer and a few other measures — would cost less than $1 a year per person in the poorest countries and about $3 per person in richer ones. For the world’s 144 low- and middle-income nations, the investment would be at least $11.4 billion.

That’s the conclusion of a long-awaited estimate by the World Health Organization in the war against the world’s latest enemy: “noncommunicable diseases.”

But many unanswered questions linger: Who’s going to foot the bill? And is the world really ready for another global campaign against disease?

The price for the “best buys” in prevention was unveiled Sunday on the eve of a two-day meeting at the United Nations to discuss the growing epidemic of these ailments, chiefly heart attack, stroke, cancer, diabetes, and chronic lung conditions such as emphysema and asthma. Together they account for 63 percent of deaths each year.

Despite their stereotype as being “diseases of affluence,” the vast majority occur in the developing world. People in sub-Saharan Africa and parts of Central and Southeast Asia are three times more likely to die of them before age 60 than are Americans and Europeans.