Prevalence of the major rheumatic disorders in the adult population of north Pakistan.

The prevalence of rheumatic diseases in developing countries is largely unknown. Studies which allow comparison of data within the contrasting communities of the Third World and the developed world have the potential to provide insights into disease aetiologies. The current study compared the frequency of rheumatic symptoms (point prevalence) amongst 1997 adults distributed evenly between poor rural and poor urban communities and relatively affluent urban people. Comparisons were also made with similarly but previously derived prevalence rates of rheumatic symptoms and rheumatoid arthritis (RA) in south Pakistan and Pakistanis in England. A significantly higher prevalence of joint pain was seen in the north compared with the south. RA was more common in the north and similar to the frequency amongst Pakistanis resident in England. Ethnic and genetic susceptibility might have accounted for this. There was significantly more soft-tissue rheumatism and back pain in the northern rural population compared with those in the city. Fibromyalgia was almost completely absent from the urban affluent, but osteoarthritis of the knee was significantly more common in this community, perhaps due to relative obesity. RA was least in the urban poor, a phenomenon that might be attributable to earlier death of females or other undetermined factors.