Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Nora L. Valdiviezo is active.

Publication


Featured researches published by Nora L. Valdiviezo.


Journal of Chronic Diseases | 1983

Underlying cause of death as recorded for multiple sclerosis patients: Associated factors

Roberta M. Malmgren; Nora L. Valdiviezo; Barbara R. Visscher; Virginia A. Clark; Roger Detels; Marianne Fukumoto; Jan P. Dudley

The coding of multiple sclerosis (MS) as underlying cause of death (UCD) on the death certificate provides an important epidemiologic resource for both descriptive and analytic studies. However, not all deaths among MS patients will be so coded. We investigated the effect on estimated occurrence of MS and on characteristics of MS patients when only UCD codes are used to identify cases. Of 2329 MS patients living in Los Angeles County (California) or King/Pierce Counties (Washington) in 1970, 438 had died by 1980. Only 53% of the deaths were coded to MS; 47% were attributed to other causes. Based on our comparisons, the use of only MS-coded deaths to describe decedents would: underestimate the age at MS onset; overestimate the female:male ratio; underestimate age at death; and underestimate duration of MS. Also, the percentage of MS-coded deaths decreased with lengthening duration of follow-up of these prevalent cases. The effect of using only UCD codes to report characteristics of decedents with other chronic diseases may well be similar.


Journal of Neurology | 1981

Two populations with multiple sclerosis

Barbara R. Visscher; Virginia A. Clark; Roger Detels; Roberta M. Malmgren; Nora L. Valdiviezo; Jan P. Dudley

SummaryCross-sectional data from 1,793 cases of definite or probable multiple sclerosis (MS) identified in an extensive population survey in King and Pierce (K-P) Counties, Washington and Los Angeles (LA) County, California, were analyzed. Compared to the U.S. population as a whole, patients were more likely to be divorced and to have more years of schooling. The prevalence of MS was higher for females, and for northern-born, regardless of sex. Reconstructed age-, sex-specific incidence rate estimates for natives of the two areas showed a much higher peak annual incidence occurring in an older age group in K-P than in LA. Earliest symptoms in both areas were numbness in the legs, double vision, and loss of vision in one or both eyes. Weakness in arms, speech difficulties, and urinary incontinence tended to be late symptoms. The overall assessment of disability levels showed more than half of the patients to be fully ambulatory at the time of the first interview, with a somewhat higher proportion of each sex severely disabled in California. The ages of onset tended to be younger in LA than in K-P. The earlier onset of disease and the higher proportion of patients with high disability in Los Angeles County suggest that the course of disease is more malignant in this low-prevalence area.ZusammenfassungEs wurden Durchschnittsdaten von 1793 Fällen definitiver und wahrscheinlicher Multipler Sklerose (MS) analysiert, die in umfangreichen Bevölkerungserhebungen identifiziert wurden, in den Landkreisen King und Pierce (K-P) in Washington und in dem Landkreis Los Angeles (LA). Verglichen mit der Gesamtbevölkerung der Vereinigten Staaten, waren die Patienten häufiger geschieden und hatten mehr Jahre Schulung. Das Auftreten von MS war häufiger bei weiblichen Personen und bei solchen, die im Norden geboren waren, ungeachtet des Geschlechts. Die Schätzungen der Rate der rekonstruierten alters- und geschlechtsspezifischen Fälle für die Einwohner der zwei Gebiete zeigt einen viel höheren Höchstwert von jährlichem Fallauftreten bei den älteren Altersgruppen in K-P als in LA. Erste Symptome in beiden Gegenden waren Gefühllosigkeit in den Beinen, Doppelsichtigkeit und Verlust des Sehvermögens auf einem oder beiden Augen. Schwäche in den Armen, Sprachschwierigkeiten und Harnfluß waren mehr spätere Symptome. Die Gesamtbewertung der Behinderungsstadien zeigte, daß mehr als die Hälfte der Patienten zur Zeit des ersten Interviews völlig ambulant waren, mit einem etwas höheren Anteil an schwer behinderten bei Personen von beiderlei Geschlecht in Kalifornien. Das Alter bei Beginn neigte in LA jünger zu sein als in K-P. Das frühere Anfangsalter der Krankheit und der höhere Anteil von Patienten mit schwerer Behinderung in dem Landkreis Los Angeles weist auf einen bösartigeren Verlauf in diesem Gebiet mit geringer Verbreitung.


Journal of Neurology | 1981

Relationship between measles HI titers and an MS susceptibility gene.

Robert W. Haile; Barbara R. Visscher; Roger Detels; Nora L. Valdiviezo; John L. Sever; David L. Madden

SummaryRecently published studies of formal linkage analyses strongly suggest that a multiple sclerosis susceptibility (MSS) gene is linked to the HLA region of the sixth chromosome. The objective of this analysis was to investigate whether or not the gene has any demonstrable relationship to the immune status with regard to measles within members of multiple-case MS families. Family members were HLA-typed, and levels of antibodies to measles were determined using the hemagglutination inhibition assay. Since a specific, HLA-defined haplotype within each family is presumably a marker for the MSS gene, family members were characterized as either carrying [(+) controls] or not carrying [(−) controls] the MSS gene by the presence of this specific haplotype. Twenty families were entered into the analyses. Results revealed that the mean titer to measles was not different between (+) and (−) controls, and that MS cases had significantly higher titers than both control groups combined.ZusammenfassungVor kurzem veröffentlichte Studien über die formale Verbindungs-Analyse lassen sehr stark vermuten, daß ein Anfälligkeitsgen für Multiple Sklerose (MSS) mit der HLA-Region des sechsten Chromosoms verbunden ist. Es war das Ziel der Analyse, zu untersuchen, ob das Auftreten dieses Gens irgendeine nachweisbare Verbindung mit dem Immunestatus in bezug auf Masern unter den Mitgliedern von Familien mit mehrfachen Fällen von MS hat. Die Familienmitglieder waren HLA-Typen, und die Anzahl der Antikörper für Masern wurde durch die Hämagglutination-Inhibition-Probe bestimmt. Da ein spezifischer, HLA-bestimmter Haplotype innerhalb jeder Familie als Kennzeichen für das MSS-Gen angenommen wird, wurden die Familienmitglieder als Träger [(+)-Kontrolle] oder Nichtträger [(−)-Kontrolle] des MSS-Gens durch das Auftreten dieses spezifischen Haplotypen bestimmt. Zwanzig Familien nahmen an der Analyse teil. Die Resultate zeigten, daß der Durchschnittstiter für Masern zwischen den (+)- und (−)-Kontrollen nicht unterschiedlich war, und daß die MS-Fälle wesentlich höhere Titer hatten als beide Kontrollgruppen zusammen.


Neuroepidemiology | 1983

Role of Heat in Multiple Sclerosis Symptoms in a High- and a Low-Prevalence Area

Barbara R. Visscher; Roger Detels; Virginia A. Clark; Roberta M. Malmgren; Jan P. Dudley; Nora L. Valdiviezo

A significantly higher proportion of Los Angeles County (State of California, USA) multiple sclerosis patient than of King-Pierce Counties (State of Washington, USA) patients, interviewed as part of a


Neuroepidemiology | 1983

Serum Immune Complex Levels in Multiple Sclerosis Cases and Their Unaffected Siblings

Constance B. Sullivan; Linda M. Karavodin; Nora L. Valdiviezo; Roger Detels; Barbara R. Visscher; Jan P. Dudley

To determine whether the multiple sclerosis susceptibility (MSS) gene has an effect on serum immune complex (IC) levels, we used the solid-phase Clq binding assay to test for the presence of IC in ser


JAMA Neurology | 1982

Factors Associated With a Rapid Course of Multiple Sclerosis

Roger Detels; Virginia A. Clark; Nora L. Valdiviezo; Barbara R. Visscher; Roberta M. Malmgren; Jan P. Dudley


JAMA | 1982

Factors Associated With a Malignant or Benign Course of Multiple Sclerosis

Virginia A. Clark; Roger Detels; Barbara R. Visscher; Nora L. Valdiviezo; Roberta M. Malmgren; Jan P. Dudley


Journal of Neurology | 1981

Two populations with multiple sclerosis. Clinical and demographic characteristics.

Barbara R. Visscher; Virginia A. Clark; Roger Detels; Roberta M. Malmgren; Nora L. Valdiviezo; Jan P. Dudley


Journal of Neuroimmunology | 1981

Similar levels of immune complexes in cases of multiple sclerosis and their unaffected relatives

Robert W. Haile; Linda M. Karavodin; Barbara R. Visscher; Roger Detels; Nora L. Valdiviezo


American Journal of Epidemiology | 1984

APPLICATION OF SIMULATION TECHNIQUES FOR ESTIMATING DURATION OF MULTIPLE SCLEROSIS DERIVED FROM PREVALENCE-FORMED COHORTS

Virginia A. Clark; Barbara R. Visscher; Roger Detels; Nora L. Valdiviezo; Roberta M. Malmgren; Jan P. Dudley

Collaboration


Dive into the Nora L. Valdiviezo's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar

Roger Detels

University of California

View shared research outputs
Top Co-Authors

Avatar

Jan P. Dudley

University of California

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

David L. Madden

National Institutes of Health

View shared research outputs
Top Co-Authors

Avatar

John L. Sever

National Institutes of Health

View shared research outputs
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge