Is the reported high mortality from cerebrovascular disease in Japan really an artefact?

Incidence of stroke in Shibata, Japan: 1976-1978

A stroke registry was established in Shibata City, Niigata Prefecture, Japan (population 75,000) in 1976. WHO recommendations for criteria were followed. This paper reports stroke incidence for the initial 3 years of the registry: 1976 through 1978. All living patients were examined clinically by a staff physician. Only patients with a diagnosis of first stroke were included in the study. Sensitivity of the referral system was estimated at 85 + %, comparable to that in American studies. Average annual incidence per 1,000 in resident greater than or equal to 20 years was 2.61 for all strokes (3.42 for males; 1.88 for females), 0.20 for subarachnoid hemorrhage, 0.61 for cerebral hemorrhage, 1.51 for cerebral infarction - rates similar to those reported 10-20 years previously for the United States. The male-female ratio, 2:1, reflected a high rate among males, low among females. Rats among Shibata males were higher than 1972 U.S. rates reported by the Epidemiologic Study Group; rates among Shibata females were lower than corresponding U.S. rates. Incidence of all strokes combined increased with age, the age relationship being strongest for cerebral infarction. No subarachnoid hemorrhage was observed in Shibata residents greater than or equal to 70 years of age.

Stroke in Melbourne, Australia: an epidemiological study

A population-based stroke incidence study was carried out in Melbourne, Australia, between March 1978 and September 1979. Age-sex specific incidence rates were calculated and shown to be similar to those reported from the United States. At 18 months after the onset of stroke 55% of patients were alive and the probability of survival was shown to be related to the level of consciousness at time of maximum impairment. Seasonal variability of stroke incidence was demonstrated, as was an association between incidence rates and country of birth.