Quote: "ASR = age-standardised rates: These are a summary measure of the rate of disease that a population would have if it had a standard age structure. Standardisation is necessary when comparing populations that differ with respect to age, because age has a powerful influence on the risk of dying from cancer."
There are many factors increasing the risk of mouth cancer, the most common ones being tobacco and alcohol consumption. It is suspected that smoking bidi is the reason for high mouth cancer rates in South Asia. For Papua New Guinea and Bangladesh, the chewing of the betel nut is causing the high mouth cancer rate.