137 patients were actively treated because of chronic uremia, during 1966 to 1977 in the city of Göteborg. One year patient survival increased from 51% (1966 to 1968) to 81% (1975 to 1977). Peritoneal dialysis decreased as the initial mode of treatment, and only 3% of the patients started dialysis treatment with this mode of therapy in the last 3-year period. Mean age of the actively treated patients was 44 years. A decreasing mean age of the actively treated patients was found towards the end of the period, reflecting more liberal criteria for accepting young patients with different systemic diseases. If the initial mode of treatment was dialysis, 1-year patient survival in the last 3-year period was 77%.
BACKGROUND: The prevalence of angle-closure glaucoma (ACG) is greater for Eskimos/Inuit than it is for any other ethnic group in the world. Although it has been suggested that this prevalence may be due to a population tendency toward shallower anterior chamber angles, available evidence for other populations such as Chinese with high rates of ACG has not consistently demonstrated such a tendency. METHODS: A reticule, slit-lamp, and standard Goldmann one-mirror goniolens were used to make measurements in the anterior chamber (AC) angle according to a previously reported protocol for biometric gonioscopy (BG) (Ophthalmology 1999;106:2161-7). Measurements were made in all four quadrants of one eye among 133 phakic Alaskan Eskimos aged 40 years and older. Automatic refraction, dilated examination of the anterior segment and optic nerve, and A-scan measurements of AC depth, lens thickness, and axial length were also carried out for all subjects. RESULTS: Both central and peripheral AC measurements for the Eskimo subjects were significantly lower than those previously reported by us for Chinese, blacks, and whites under the identical protocol. Eskimos also seemed to have somewhat more hyperopia. There were no differences in biometric measurements between men and women in this Eskimo population. Angle measurements by BG seemed to decline more rapidly over life among Eskimos and Chinese than blacks or whites. Although there was a significant apparent decrease in AC depth, increase in lens thickness, and increase in hyperopia with age among Eskimos, all of these trends seemed to reverse in the seventh decade and beyond. CONCLUSIONS: Eskimos do seem to have shallower ACs than do other racial groups. Measurements of the AC angle seem to decline more rapidly over life among Eskimos than among blacks or whites, a phenomenon also observed by us among Chinese, another group with high ACG prevalence. This apparent more rapid decline may be due to a cohort effect with higher prevalence of myopia and resulting wider angles among younger Eskimos and Chinese.
To assess and analyze refractive outcome after cataract surgery in Sweden from 2008 through 2010.
Swedish cataract surgery units participating in outcome registration of National Cataract Register.
Planned and actual postoperative refractions were analyzed for cataract procedures and preoperative and postoperative corneal astigmatism for procedures performed in 2008 though 2010. Induced astigmatism was calculated with Naeser and Behrens polar coordinates.
Postoperative refraction was analyzed for 17,056 procedures and corneal astigmatism for 7448 procedures. Emmetropia was targeted in 78.1% of eyes and achieved in 52.7%; 43.0% had less than 1.00 diopter (D) of astigmatism. "Reading myopia" of -3.5 to -1.6 D was targeted in 7.0% of eyes and achieved in 7.8%. Planned hyperopia greater than 1.0 D or myopia greater than -3.5 D was rare. The mean absolute biometry prediction error was 0.402 D ± 0.338 (SD) in all eyes; however, astigmatic eyes and eyes planned for myopia or hyperopia had higher biometry prediction errors. Younger patients were more often astigmatic and planned for a more myopic outcome. Preoperatively, one third of eyes had more than 1.0 D of corneal astigmatism; postoperatively this figure was largely unaltered. The mean induced astigmatism was 0.525 ± 0.804 D in all eyes.
Emmetropia (spherical equivalent -0.5 to +0.5 D and
Epidemiologic studies examining the risk of cancer among occupational groups exposed to electric fields (EF) and or magnetic fields (MF) have relied on traditional summaries of exposure such as the time weighted arithmetic or geometric mean exposure. Findings from animal and cellular studies support the consideration of alternative measures of exposure capable of capturing threshold and intermittent measures of field strength. The main objective of this study was to identify a series of suitable exposure metrics for an ongoing cancer incidence study in a cohort of Ontario electric utility workers. Principal components analysis (PCA) and correlational analysis were used to explore the relationships within and between series of EF and MF exposure indices. Exposure data were collected using personal monitors worn by a sample of 820 workers which yielded 4247 worker days of measurement data. For both EF and MF, the first axis of the PCA identified a series of intercorrelated indices that included the geometric mean, median and arithmetic mean. A considerable portion of the variability in EF and MF exposures were accounted for by two other principal component axes. The second axes for EF and MF exposures were representative of the standard deviation (standard deviation) and thresholds of field measures. To a lesser extent, the variability in the exposure variable was explained by time dependent indices which consisted of autocorrelations at 5 min lags and average transitions in field strength. Our results suggest that the variability in exposure data can only be accounted for by using several exposure indices, and consequently, a series of metrics should be used when exploring the risk of cancer owing to MF and EF exposure in this cohort. Furthermore, the poor correlations observed between indices of MF and EF reinforce the need to be take both fields into account when assessing the risk of cancer in this occupational group.
A frailty model for multivariate correlated life times is considered. The model both extends, in a rather straight-forward way, ordinary survival analysis with its emphasis on hazard modeling and incorporates well-known variance components models to account for the dependence between events of related individuals. Different approaches to estimation and inference are considered. An example from an ongoing study of genetic and environmental influences on premature death in adults serves to motivate and illustrate the model. Multivariate frailty models offer a conceptually simple and promising framework for analysis of correlated event times data, even if current knowledge is too sparse for such models to be tested critically.
The object of the investigation reported in this paper was to study, from the point of view of statistical and geometric theory of pattern recognition, the DNA optical density distribution peculiarities in the interphase nuclei of buccal epithelium present in the pathology of the thyroid and mammary glands. Two new indices to characterize this distribution (ratio of modal class volumes and relief index) are proposed. It is shown that in malignant neoplasms of the thyroid and mammary glands the changes in the nuclei of buccal epithelium are characterized by an increase in the optical density of DNA over a range from 0.15 to 0.30 in conventional units of measure, as compared with its values in benign pathological processes. The sensitivity of the proposed criterion for diseases of the thyroid gland is equal to 76.2% and the specificity is equal to 85.8%. For diseases of the mammary gland (excluding IDLC) we have discovered that the sensitivity of the method is equal to 94.29% and its specificity equal to 90.91%. In diseases of the mammary gland (including IDLC) we have discovered that the sensitivity of the method is equal to 71.42% and its specificity is equal to 90.91%.
Epidemiologists sometimes study the association between two measurements of exposure on the same subjects by grouping the original bivariate continuous data into categories that are defined by the empirical quantiles of the two marginal distributions. Although such grouped data are presented in a two-way contingency table, the cell counts in this table do not have a multinomial distribution. We describe the joint distribution of counts in such a table by the term empirical bivariate quantile-partitioned (EBQP) distribution. Blomqvist (1950, Annals of Mathematical Statistics 21, 539-600) gave an asymptotic EBQP theory for bivariate data partitioned by the sample medians. We demonstrate that his asymptotic theory is not correct, however, except in special cases. We present a general asymptotic theory for tables of arbitrary dimensions and apply this theory to construct confidence intervals for the kappa statistic. We show by simulations that the confidence interval procedures we propose have near nominal coverage for sample sizes exceeding 60 for both 2 x 2 and 3 x 3 tables. These simulations also illustrate that the asymptotic theory of Blomqvist (1950) and the methods that Fleiss, Cohen, and Everitt (1969, Psychological Bulletin 72, 323-327) give for multinomial tables can yield subnominal coverage for kappa calculated from EBQP tables, although in some cases the coverage for these procedures is near nominal levels.
The genetics of primary angle-closure glaucome (a.c.g.) was studied: a) through the prevalence in sibs and children of a.c.g. probands, and b) through the family distribution of the closely correlated axial anterior chamber depth (ACD). The material emerged from an epidemiologic study in Greeland Eskimos. a) Compared with the general population, the observed prevalence of a.c.g. was increased in sibs of a.c.g. probands and the estimated, future prevalence was found to be the same in sibs and children. Age influence prevented a proper Mendelian analysis, but no simple monogenic inheritance seems probable. b) The biometric study showed a relatively shallow chamber in sibs, children, nephews, nieces and grandchildren of a.c.g. probands. Regression analyses revealed a corresponding pattern, also in control families of probands with shallow chambers and in general population families. A heritability of 70% was found, indicating that about two thirds of the age and sex independent variation in ACD seems to be genetic.