Objective: To investigate the role of a patent foramen ovale in the pathogenesis of multiple brain lesions acquired by sport divers in the absence of reported decompression symptoms. Design: Prospective double blind cohort study. Setting: Diving clubs around Heidelberg and departments of neuroradiology and neurology. Subjects: 87 sport divers with a minimum of 160 scuba dives (dives with self contained underwater breathing apparatus). Main outcome measures: Presence of multiple brain lesions visualised by cranial magnetic resonance imaging and presence and size of patent foramen ovale as documented by echocontrast transcranial Doppler ultrasonography. Results: 25 subjects were found to have a right-to-left shunt, 13 with a patent foramen ovale of high haemodynamic relevance. A total of 41 brain lesions were detected in 11 divers. There were seven brain lesions in seven divers without a right-to-left shunt and 34 lesions in four divers with a right-to-left shunt. Multiple brain lesions occurred exclusively in three divers with a large patent foramen ovale (P = 0.004). Conclusions: Multiple brain lesions in sport divers were associated with presence of a large patent foramen ovale. This association suggests paradoxical gas embolism as the pathological mechanism. A patent foramen ovale of high haemodynamic relevance seems to be an important risk factor for developing multiple brain lesions in sport divers.

Diabetes and hypertension are much more prevalent among Britain's 2.5 million Asian and African-Caribbean population than among the white population and are major contributors to end stage renal failure. Asians and African-Caribbeans have threefold to fourfold higher acceptance rates on to renal replacement therapy than white people, and in some districts they comprise up to half of all patients receiving such treatment. Their greater need for renal replacement treatment is accompanied by difficulties of tissue matching in cross racial transplants and a shortage of donor organs. The aging of ethnic minority populations will increase local need for renal services significantly. Measures to control diabetes, hypertension, and secondary complications in Asian and African-Caribbean communities will contribute both to safeguarding health and to economies in spending on renal services. Education about diabetes and hypertension, modification of behavioural risk factors, early diagnosis, effective glycaemic and blood pressure control, and early referral for signs of renal impairment are essential preventive measures. Primary and community health care professionals have a critical role to play here.