A new World Health Organization report says five billion people worldwide have suffered from tooth decay and that oral disease is fast becoming a problem in both rich and poor nations.

The report released Tuesday in Geneva says gum disease, rotting teeth, and oral cancer cause tremendous pain, reduce the quality of life, and, for many countries, are expensive to treat.

It calls tooth decay the most prevalent oral disease in many Asian and Latin American countries. It also predicts the problem will grow in Africa as consumption of sugar rises and exposure to fluoride drops.

The WHO calls smoking, chewing tobacco, and alcohol major risk factors for gum disease in developed countries.

The report recommends that oral health programs stress greater prevention, including decreasing sugar consumption, stopping smoking, and eating a more nutritious diet.