Dan, you might be interested in this 2011 paper that highlights just how enormous bladder problems are on a global scale (so it's not limited to industrialised nations). The paper estimates the current and predicted prevalence of people suffering lower urinary tract symptoms (LUTS), overactive bladder (OAB), urinary incontinence (UI) and bladder outlet obstruction (BOO).
The paper projects that LUTS etc, a highly prevalent condition worldwide, will only increase with time - with a particular increase in burden in developing counties such as Asia, Africa and South America.
"An estimated 45.2%, 10.7%, 8.2% and 21.5% of the 2008 worldwide population (4.3 billion) was affected by at least one LUTS, OAB, UI and LUTS/BOO, respectively. By 2018, an estimated 2.3 billion individuals will be affected by at least one LUTS (18.4% increase), 546 million by OAB (20.1%), 423 million by UI (21.6%) and 1.1 billion by LUTS/BOO (18.5%)."
I know this paper doesn't mention IC/PBS as such, but to me that's well and truly covered by LUTS, OAB, UI and BOO.
http://onlinelibrary.wiley.com/doi/10.1111/j.1464-410X.2010.09993.x/full