Incidence of urinary stones in the various states of mainland Malaysia.

Andersen (1969) in his work on the historical and geographical differences in the pattern of incidence of urinary stones had noted that "there is evidence of a different stone incidence in the industrialised and developing group of countries". He had feared that if an attempt was not made early to study the process of change in the underdeveloped countries it may not be possible to discover aetiological factors before there is a disappearance of "endemic" stones in these areas.