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Part I of this report appeared in the previous issue (Br. J. Cancer (1976) 34,585), and discussed the design of randomized clinical trials. Part II now describes efficient methods of analysis of randomized clinical trials in which we wish to compare the duration of survival (or the time until some other untoward event first occurs) among different groups of(More)
The Medical Research Council has for some years encouraged collaborative clinical trials in leukaemia and other cancers, reporting the results in the medical literature. One unreported result which deserves such publication is the development of the expertise to design and analyse such trials. This report was prepared by a group of British and American(More)
Average annual age-adjusted incidence rates of parkinsonism-dementia complex were obtained for the 19 election districts of Guam from 1956 through 1985. The highest rates were found in the southern and central districts, and the lowest rates were found in the northern and western districts. Geographic and temporal patterns of incidence were associated with(More)
We investigated the geographic and familial occurrence of motor neuron disease (MND) on Guam, and then considered etiologic hypotheses related to cycad use and metal intoxication. The research was based on 303 Chamorros from Guam and 3 Chamorros from other Mariana Islands, all with MND onset on Guam during 1956-85. Inarajan and Umatac, two southern(More)
A previous study of twins with Parkinson's disease (PD) revealed low concordance, suggesting that genetic factors play a minor role in the etiology of PD. To identify possible environmental determinants of PD while maximally controlling for hereditary factors, 31 monozygotic twin pairs discordant for PD were interviewed by telephone. Information about(More)
A test for homogeneity of the effect of a factor in inducing disease in the various strata of a population should relate to the scaling in which homogeneity is anticipated. Popularity, it is the multiplicative effect on the odds ratio in which homogeneity is anticipated. An asymptotic test by M. Zelen (Biometrika 58:129-137, 1971) for homogeneity in this(More)
The principles of the Ederer-Myers-Mantel procedure for seeking evidence of disease clustering are reviewed. The procedure is based on cumulative empirical clusters, i.e., the largest frequency in a single time period or in two successive time periods, and comparing that cumulation with the expected cumulation of largest frequencies under random occurrence.(More)
Using a case registry, we investigated the temporal occurrence of motor neuron disease (MND) on Guam. MND with onset during 1941-85 was documented in 434 Chamorros and 9 non-Chamorro migrants who had lived on Guam before onset. Increased median age at onset and decreased age-adjusted incidence rates (since the early 1960s) were observed for Chamorros of(More)
Statistical techniques used for surveillance of disease incidence rates are generally based on the assumption of known baseline rate of the disease monitored, whereas actually it is an estimate obtained from a large sample. As a result, the time interval until true or false alarm is shorter or longer than assumed. In this study, we evaluate the performance(More)
For 1944 through 1985, documented clinical descriptions compatible with a diagnosis of parkinsonism-dementia complex were found in 363 Chamorros (including mixed Chamorros) and three Filipino immigrants who had lived on Guam before onset. Downward trends in age-adjusted incidence rates and upward trends in age at onset were seen for Chamorros of both sexes.(More)