Does running exercise cause osteoarthritis?

A survey of 1.3 million schoolchildren in Zimbabwe identified a total of 278 pupils with oculocutaneous albinism (OCA), giving a prevalence of 1 in 4728. Pupils with OCA were identified in every province of the country, but the distribution was not even. In certain areas, notably the capital, Harare, and the eastern province of Manicaland, the frequency was significantly higher than in others. Although most of the pupils with albinism belonged to the majority Shona ethnic group, people with OCA were also found among the minority population groups in the country. There were almost twice as many pupils with albinism in rural compared with urban schools (248 v 129). However, the prevalence of OCA was significantly higher in urban than rural areas. These results indicate that data for a country collected solely in urban locations are likely to be biased and emphasise the need for widespread distribution of health and special educational facilities for affected people.