prevalence = epidemic ?

In epidemiology, one considers the incidence and the prevalence of any disease condition. The incidence is the raw number of cases, and the prevalence is the number of cases (usually expressed as a proportion) in the population at any time. The author is saying that the cost of dealing with senile dementia will rise faster than the number of cases which can be identified within the population.

prevalence = trend

doubling, then tripling numbers of the disease.

Prevalence means:

- the quality of prevailing generally; being widespread; "he was surprised by the prevalence of optimism about the future"

- (epidemiology) the ratio (for a given time period) of the number of occurrences of a disease or event to the number of units at risk in the population

Unfortunately Punkey has given a misleading answer, I am sorry to say.

That's a prevalent disease.

I still think the word prevalence in this sentence is referring to the rapid increase in occurances. The phrase after the word prevelance (the antecedent) further explains the numbers dilemma.

punkey, you are confused.

The costs of caring for people with dementia are likely to rise even faster than (the rise in) the prevalence (note spelling). The prevalence is the frequency of occurrence (note spelling) or the degree to which dementia is widespread.

Thanks.

Thank you all.