Certainty of the Global Burden of Disease 2019 Modelled Prevalence Estimates for Musculoskeletal Conditions: A Meta-Epidemiological Study

Objectives: To describe and assess the risk of bias of the primary input studies that underpinned the Global Burden of Disease Study (GBD) 2019 modelled prevalence estimates of low back pain (LBP), neck pain (NP), and knee osteoarthritis (OA), from Australia, Brazil, Canada, Spain, and Switzerland. To evaluate the certainty of the GBD modelled prevalence evidence. Methods: Primary studies were identified using the GBD Data Input Sources Tool and their risk of bias was assessed using a validated tool. We rated the certainty of modelled prevalence estimates based on the GRADE Guidelines 30-the GRADE approach for modelled evidence. Results: Seventy-two primary studies (LBP: 67, NP: 2, knee OA: 3) underpinned the GBD estimates. Most studies had limited representativeness of their study populations, used suboptimal case definitions and applied assessment instruments with unknown psychometric properties. The certainty of modelled prevalence estimates was low, mainly due to risk of bias and indirectness. Conclusion: Beyond the risk of bias of primary input studies for LBP, NP, and knee OA in GBD 2019, the certainty of country-specific modelled prevalence estimates still have room for improvement.

The increasing significance of disease severity in a burden of disease framework

Recent estimates have reiterated that non-fatal causes of disease, such as low back pain, headaches and depressive disorders, are amongst the leading causes of disability-adjusted life years (DALYs). For these causes, the contribution of years lived with disability (YLD) - put simply, ill-health - is what drives DALYs, not mortality. Being able to monitor trends in YLD closely is particularly relevant for countries that sit high on the socio-demographic spectrum of development, as it contributes more than half of all DALYs. There is a paucity of data on how the population-level occurrence of disease is distributed according to severity, and as such, the majority of global and national efforts in monitoring YLD lack the ability to differentiate changes in severity across time and location. This raises uncertainties in interpreting these findings without triangulation with other relevant data sources. Our commentary aims to bring this issue to the forefront for users of burden of disease estimates, as its impact is often easily overlooked as part of the fundamental process of generating DALY estimates. Moreover, the wider health harms of the COVID-19 pandemic have underlined the likelihood of latent and delayed demand in accessing vital health and care services that will ultimately lead to exacerbated disease severity and health outcomes. This places increased importance on attempts to be able to differentiate by both the occurrence and severity of disease.

Measuring health expectancy in the European Union

Background

Healthy life expectancy (HLE) is a population health measure that combines mortality and morbidity, which can be calculated using different methods. In this study, we aimed to assess the correlation, reliability and (dis)agreement between two estimates monitored in the European Union (EU), that is, the European Commission's HLE based on self-perceived health (SPH-HLE) and the Institute for Health Metrics and Evaluation's HLE based on disability weight (DW-HLE), by sex, and comparing these results with LE and proportion of life spent in good health (%GH).

Methods

We performed a retrospective study in the EU28 countries, between 2010 and 2017. The HLE methods differ in definition, measurement and valuation of health states. While SPH-HLE relies directly on one question, DW-HLE relies on epidemiological data adjusted for DW. Spearman's r, intraclass correlation coefficient, information-based measure of disagreement and Bland-Altman plots were used to assess reliability, correlation and disagreement in HLE resulting from both methods and in LE or %GH measured by both institutions.

Results

Correlation and reliability between SPH-HLE and DW-HLE were good (better for males), with low disagreement, and were even better for LE between both institutions. The HLE Bland-Altman plots suggest a variability range of approximately 6 years for both sexes, higher for females. There was also an increasing HLE difference between methods with higher average HLE for both sexes.

Conclusions

We showed wide variations between both methods with a clear and different high impact on female and male HLE, showing a tendency for countries with higher health expectancies to yield larger gaps between SPH-HLE and DW-HLE.

Acknowledgements: This presentation was supported by National Funds through FCT - Fundação para a Ciência e a Tecnologia,I.P., within CINTESIS, R&D Unit (reference UIDP/4255/2020)

Key messages

• Different methods for evaluating health expectancy lead to significantly different results.

• There is a systematic tendency with countries with higher health expectancies to yield larger gaps between SPH-HLE and DW-HLE.

New proposed measures to evaluate contact tracing effectiveness

Issue/problem

Contact tracing is an important and widely used method to control transmission of communicable diseases. The COVID-19 pandemic presented a new and big challenge with a high number of confirmed cases and contacts and subsequent high burden on contact tracing activities. Naturally, the effectiveness of such interventions needs to be assessed, and appropriate measures are still rather underdeveloped.

Description of the problem

We propose two new measures for assessing contact tracing effectiveness: “number needed to quarantine” (NNQ), which is the number of quarantined person-days needed to prevent one infectious person-day, and the proportion of infectious days prevented by the quarantined (PPID). We have applied these measures to assess COVID-19 contact tracing effectiveness in COVID-19 confirmed cases diagnosed between July and mid-September 2020 in a local Public Health Unity in the Northern region of Portugal (Espinho/Gaia). For robustness checks and accounting for the uncertainty of the infectiousness period, we used three different scenarios.

Results

Depending on the infectiousness period considered, we have found a NNQ between 19.8 and 41.8 and a PPID between 19.7% and 38.2%. Contact tracing effectiveness was higher for some specific groups such as cohabitants and symptomatic contacts. Effectiveness also decreased with the increasing time from diagnosis or symptom onset to contact isolation

Lessons

NNQ and PPID are straightforward and easy to use measures to evaluate contact tracing effectiveness in communicable diseases. Although this example focuses in the COVID-19 pandemic at a local setting, these measures can also be used for different communicable diseases and at different levels. This assessment step can be important for priority setting of transmission control activities but also on a health management perspective.

Key messages

• New measures to evaluate contact tracing effectiveness are proposed: “number needed to quarantine” and “proportion of prevented infectious days”.

• These measures allow the identification of priority groups that must be quarantined, as well as time periods of intervention, for better transmission control.

What does it mean to age in good health? An analysis of Time Use Survey data

Background

While there is intrinsic value of ageing in good health, there is little evidence of how the daily lives of older people differ depending on their health status.

Methods

We use Time Use Survey data from the United Kingdom to assess how people at different ages spend their time, conditional on their self-reported health.

Results

While results are preliminary, we find stark differences between people's time use dependent on their health. For example, older people who report good health are more likely than comparable older people to engage in paid work, volunteer, and participate in leisure activities.

Conclusions

There are many benefits to supporting healthy ageing. By considering how time spent differs between those in good and poor health and attributing value to that time, one can take a more holistic perspective when conducting cost-benefit analysis of policy interventions.

Primary care organizational model mix and avoidable hospitalization: an ecological study in Portugal

Background

In Portugal, there are different organizational models in primary health care (PHC), mainly regarding the payment scheme. USF-B is the only type with financial incentives to the professional (pay-for-performance). Our goal was to assess the relationship between groups of primary healthcare centres (ACES) with higher proportion of patients within USF-B model and the rate of avoidable hospitalizations, as proxy of primary care quality.

Methods

We conducted a cross-sectional study considering the 55 ACES from mainland Portugal, in 2017. We used data from public hospitalizations to calculate the prevention quality indicator (avoidable hospitalizations) adjusted for age and sex, using direct standardization. The main independent variable was the proportion of patients in one ACES registered in the USF-B model. Unemployment rate, proportion of patients with family doctor and presence of Local Health Unit (different organization model) within ACES were also considered. The association was assessed by means of a linear regression model.

Results

Age-sex adjusted PQI value varied between 490 and 1715 hospitalizations per 100,000 inhabitants across ACES. We observed a significant effect of the proportion of patients within USF-B in the crude PQI rate (p = 0.001). However, using the age-sex adjusted PQI, there was not a statistical significant association (p = 0.504). This last model was also adjusted for confounding variables and the association remains non-significant (p = 0.865).

Conclusions

Our findings suggest that, when adjusting for age and sex, there is no evidence that ACES with more patients enrolled in a pay-for-performance model is associated with higher quality of PHC (using avoidable hospitalizations as proxy). Further studies addressing individual data should be performed.

This work was financed by FEDER funds through the COMPETE 2020 - POCI, and by Portuguese funds through FCT in the framework of the project POCI-01-0145-FEDER-030766 “1st.IndiQare”.

Key messages

Adjusting PQI to sex and age seems to influence its value more than the type of organizational model of primary health care. Groups of primary healthcare centres with more units under the pay-for-performance scheme was not associated with different rate of avoidable hospitalizations.

Efficiency of groups of primary healthcare centres: a frontier analysis of primary care in Portugal

Background

Primary health care (PHC) is the cornerstone of several health systems. The Portuguese PHC is organized in five mainland regions (ARS), that oversee 55 local groups of primary healthcare centres (ACES). We assessed the efficiency of all 55 ACES in mainland Portugal, as well as organizational and socioeconomic determinants of the efficiency.

Methods

A cross-sectional non-parametric frontier analysis was performed for 2017. The first model included two inputs (i.e. number of physicians and number of nurses) and a single output (i.e. number of PHC visits), while the second model included an additional output, i.e. Prevention Quality Indicator (PQI) overall composite (avoidable hospitalizations) adjusted for age and sex - as undesirable output. In a second stage, a (multivariate) Tobit regression was used to assess organizational and socioeconomic determinants of efficiency.

Results

In the first model, only 8 ACES (14.5%) were on the efficiency frontier, while 25 ACES should readjust their human resource balance. In the second model, 9 ACES (16.4%) were considered efficient. When considering quality, one ACES previously considered inefficient moved to the frontier and two ACES lost their benchmark position. The second-stage analysis indicates that groups with a higher proportion of PHC units with pay-for-performance incentives were associated with higher efficiency.

Conclusions

Most ACES have the potential to improve their production levels., A better management of human resources can contribute to improve overall efficiency. ACES with a higher proportion of units with pay-for-performance schemes seem to be more efficient. These findings contribute to the evaluation of policies to integrate and scale up PHC services locally, such as the recent primary care networks in the NHS UK.

This work was financed by FEDER funds through the COMPETE 2020 - POCI, and by Portuguese funds through FCT in the framework of the project POCI-01-0145-FEDER-030766 “1st.IndiQare”.

Key messages

Most Portuguese ACES have the potential to improve their outputs given their current level of human resources. Local groups that aggregate more PHC units with pay-for-performance schemes are associated with high efficiency.

Population vulnerability to COVID-19 in Europe: a burden of disease analysis

BACKGROUND

Evidence has emerged showing that elderly people and those with pre-existing chronic health conditions may be at higher risk of developing severe health consequences from COVID-19. In Europe, this is of particular relevance with ageing populations living with non-communicable diseases, multi-morbidity and frailty. Published estimates of Years Lived with Disability (YLD) from the Global Burden of Disease (GBD) study help to characterise the extent of these effects. Our aim was to identify the countries across Europe that have populations at highest risk from COVID-19 by using estimates of population age structure and YLD for health conditions linked to severe illness from COVID-19.

METHODS

Population and YLD estimates from GBD 2017 were extracted for 45 countries in Europe. YLD was restricted to a list of specific health conditions associated with being at risk of developing severe consequences from COVID-19 based on guidance from the United Kingdom Government. This guidance also identified individuals aged 70 years and above as being at higher risk of developing severe health consequences. Study outcomes were defined as: (i) proportion of population aged 70 years and above; and (ii) rate of YLD for COVID-19 vulnerable health conditions across all ages. Bivariate groupings were established for each outcome and combined to establish overall population-level vulnerability.

RESULTS

Countries with the highest proportions of elderly residents were Italy, Greece, Germany, Portugal and Finland. When assessments of population-level YLD rates for COVID-19 vulnerable health conditions were made, the highest rates were observed for Bulgaria, Czechia, Croatia, Hungary and Bosnia and Herzegovina. A bivariate analysis indicated that the countries at high-risk across both measures of vulnerability were: Bulgaria; Portugal; Latvia; Lithuania; Greece; Germany; Estonia; and Sweden.

CONCLUSION

Routine estimates of population structures and non-fatal burden of disease measures can be usefully combined to create composite indicators of vulnerability for rapid assessments, in this case to severe health consequences from COVID-19. Countries with available results for sub-national regions within their country, or national burden of disease studies that also use sub-national levels for burden quantifications, should consider using non-fatal burden of disease estimates to estimate geographical vulnerability to COVID-19.

To be or not to be hospitalised with tuberculosis in Portugal

SETTING: In Portugal, as in other countries, tuberculosis (TB) is considered a disease that should be managed on an ambulatory basis. However, hospitalisation remains important to manage some at-risk groups and complications.OBJECTIVE: To identify the possible risk factors associated with hospitalisations in TB patients in Portugal.DESIGN: Data extraction through two national databases (one for registration of TB cases and the other with hospitalisation information in public health facilities) between 2007 and 2013. Univariate and multivariate analysis of demographic and clinical variables was performed.RESULTS: We identified 4421 hospitalisations. Chronic diseases, cancer, substance abuse, a higher social/economic risk, extra-pulmonary TB, lung cavitary disease and previous uncompleted treatment were more frequent among hospitalised patients. Human immunodeficiency virus coinfection, cancer, alcohol abuse, extra-pulmonary TB and uncompleted previous TB treatment were the most important predictors of hospitalisation with TB. The hospitalisation rate among TB patients in Portugal was lower when compared with other countries with lower and higher incidences.CONCLUSION: Immune dysfunctions and progression of chronic diseases are associated with more severe forms of TB and frequent adverse effects which can be sufficiently severe to necessitate hospital admission. Despite having an intermediate TB incidence, the hospitalisation rate in Portugal is not higher than that of other countries.

Time trends of primary care quality across Portuguese regions: using prevention quality indicators

Background

Primary care quality is one of the main dimensions of primary care performance and can be evaluated by several methods, e.g. studying hospitalizations for conditions that could be treated, or less severe, if appropriately managed in primary care. Accordingly, the Agency for Healthcare Research and Quality (AHRQ) developed prevention quality indicators (PQIs). In this study, we aimed to compare PQIs and their time trends across Portuguese regions.

Methods

We performed a retrospective study, using all adult public hospital discharges in mainland Portugal, between 2011 and 2015. PQI rates for the overall (PQI 90) and composite indicators (i.e. 91 - acute, 92 - chronic, 93 - diabetes) were computed using AHRQ specifications. These rates were compared between the 5 Portuguese NUTS 2 regions of residence.

Results

From the total of 407,792 hospital discharges in mainland Portugal (2011-2015) 11.9% comprised the selected PQIs, the majority related the acute composite PQI, followed by the chronic composite PQI. The hospitalization rate of the overall PQI increased from 999.5 hospitalizations (2011) to 1231,0 hospitalizations/100,000 inhabitants (2015), with an increase in all NUTS 2 regions. In 2015, while Algarve and North had the lowest PQI rates, Centro and Alentejo showed the highest ones.

Conclusions

Between 2011 and 2015, there was an increasing trend of overall and composite PQI rates. Also, important differences between Portuguese regions were found that must be further studied.

The authors thank the support given by the Project ’POCI-01-0145-FEDER-030766’ (1st.IndiQare - Quality indicators in primary health care: validation and implementation of quality indicators as an assessment and comparison tool), funded by Fundação para a Ciência e a Tecnologia (FCT) and co-funded by Fundo de Desenvolvimento Regional (FEDER) through Operacional Competitividade e Internacionalização (COMPETE 2020).

Key messages

Between 2011 and 2015, overall prevention quality indicator rate increased in Portugal. There are great differences between Portuguese NUTS 2 regions regarding prevention quality indicators.

Paediatric burn unit in Portugal: Beds needed using a bed-day approach

INTRODUCTION

Despite the high burden of children with burns, there is not a paediatric burn unit (PBU) in Portugal. We aimed to estimate the Portuguese health care providing needs on paediatric burns.

METHODS

We performed a nation-wide retrospective study, between 2009 and 2013, among less than 16 years-old inpatients with burns that met the transfer criteria to a burn unit in Portugal. A bed-day approach was used, targeting an occupancy rate of 70-75%, and possible locations were studied. The primary outcome was the number of beds needed, and secondary outcomes were the overload and revenue for each possible number of beds in a PBU.

RESULTS

A total of 1155 children met the transfer criteria to a burn unit, representing a total of 17,371 bed-days. Occupancy rates of 11-bed, 12-bed, 13-bed and 14-bed PBU were, respectively, 79.7%, 75.3%, 71.0% and 66.8%. The 13-bed PBU scenario would represent an overload of 523 bed-days, revenue of more than 5 million Euros and a ratio of 1 PBU bed per 123,409 children.

CONCLUSIONS

Using a groundbreaking approach, the optimal number of PBU beds needed in Portugal is 13. However, as half of the patients who met burn transfer criteria are not transferred, this bed number might be overestimated if this pattern maintains, despite the underestimation with our method approach. If a PBU is to be created the preferable location is Porto. Cost-effectiveness studies should be performed.

The impact of a liberalisation law on legally induced abortion hospitalisations

OBJECTIVES

Legal abortion based purely in maternal option without fetal/maternal pathology was liberalised in Portugal in 2007 and since then abortion rates have increased substantially. The aim of this paper was to study the impact of the liberalisation of abortion by maternal request on total legal abortion related hospitalisation trends.

STUDY DESIGN

We considered hospitalisations of legal abortion (ICD-9-CM codes 635.x) with discharges from 2000 to 2014. Data was obtained from a Portuguese administrative database, which contains all registered public hospitalisations in mainland Portugal. Performed legal abortions during the same period were obtained from INE (National Statistics Institute). Hospitalisations per abortion were calculated by dividing the number of legal abortions hospitalisations per the number of legal abortions, mean ages, number of hospitalisations per age group, complications, admission type and length of stay were also analysed, throughout the study period.

RESULTS

Hospitalisations rose during the study period, (from 618 episodes in 2000 to 1,259 in 2014, with a peak of 1,603 in 2010). Since the liberalisation law was passed there was a significant decrease in the number of hospitalisations per abortion: from 1.07 in 2000 to 0.11 in 2014 (p<0.001). Furthermore, the mean age maintained stable since liberalisation (30.8 years before 2007 and 31.0 after). Abortion related hospitalisations are more frequent in women aged 25-39. A significant decrease from the emergent to the scheduled type of admission occurred from 2000 to 2014 (from 83.5% to 56.7% of emergent admissions) (p<0.001). Complications remained stable between 2000 and 2014 and delayed or excessive haemorrhage was the most frequent (4.6%).

CONCLUSIONS

Since the liberalisation, hospitalisations per abortion have decreased, reflecting the major impact that the liberalisation of legal abortion by maternal request had on abortion trends nationwide. Before the liberalisation, each abortion led to approximately one hospitalisation while after the liberalisation this trend shifted to approximately 10% of the number of abortions. Legal abortion related hospitalisations are more frequent in women aged between 25 and 39 years old, an older age group when compared to the one registered in all cases of legal abortions, reflecting the differences between those hospitalised and those who are not. Our study shows the impact that legal abortion by maternal request liberalisation law can bring to abortion and to hospitalisation trends.

Should European perinatal indicators be revisited?

OBJECTIVES

Our study presents the results of a survey of physicians and/or researchers working in 21 European countries, on their opinion about the relevance of perinatal indicators, in order to compare it with the EURO-PERISTAT recommendations.

STUDY DESIGN

In this cross-sectional study, we selected 21 out of the initial set of 34 indicators of the national data supply on the European Perinatal Health Report, and added four other indicators based on expert opinion. The relative relevance of these 25 perinatal indicators was then rated by 134 respondents--expert physicians and/or researchers who have published in perinatal medicine--through a web-based survey. We summarized our data using descriptive statistics.

RESULTS

The top five perinatal indicators, according to the respondents' rating were: neonatal mortality rate by gestational age, birth weight and plurality; percentage of highly preterm babies delivered in units without a NICU; prevalence of severe maternal morbidity; severe neonatal morbidity among babies at high risk and prevalence of hypoxic-ischemic encephalopathy. Of these top five indicators, however, only neonatal mortality rate by gestational age, birth weight and plurality was considered a core indicator, in 2003. Moreover, severe neonatal morbidity among babies at high risk and prevalence of hypoxic-ischemic encephalopathy, that were considered in 2003 as requiring further development, were now considered by the respondents as highly relevant.

CONCLUSIONS

Current views of European physicians and/or researchers working in the perinatal field may not be in agreement with the EURO-PERISTAT recommendations. A revision of the set of perinatal indicators is, therefore, mandatory if a more comprehensive view of health care systems performance across Europe is to be achieved.

Clinical heterogeneity of autosomal recessive spastic paraplegias: analysis of 106 patients in 46 families

BACKGROUND

Hereditary spastic paraplegias (HSPs) are a heterogeneous group of neurodegenerative disorders characterized by progressive and predominant spasticity of the lower limbs, in which dominant, recessive, and X-linked forms have been described. While autosomal dominant HSP has been extensively studied, autosomal recessive HSP is less well known and is considered a rare condition.

OBJECTIVE

To analyze the clinical presentation in a large group of patients with autosomal recessive HSP from Portugal and Algeria to define homogeneous groups that could serve as a guide for future molecular studies.

RESULTS

Clinical features in 106 patients belonging to 46 Portuguese and Algerian families with autosomal recessive HSP are presented, as well as the results of molecular studies in 23 of these families. Five phenotypes are defined: (1) pure early-onset families, (2) pure lateonset families, (3) complex families with mental retardation, (4) complex families with mental retardation and peripheral neuropathy, and (5) complex families with cerebellar ataxia. Six additional families have specific complex presentations, each of which is unique in the present series. Pyramidal signs in the upper limbs and pes cavus are frequent findings, while pseudobulbar signs, including dysarthria, dysphagia, and brisk jaw jerks, are more frequent in the complex forms. The complex forms have a poorer prognosis, while pure forms, particularly those with early onset, are more benign. One Algerian pure early-onset kindred was linked to the locus on chromosome 8, previously reported in 4 Tunisian families. Two of the Portuguese kindreds with complex forms (one with mental retardation and the other associated with hypoplasia of the corpus callosum) showed linkage to the locus recently identified on chromosome 16.

CONCLUSIONS

Although autosomal recessive HSP represents a heterogeneous group of diseases, some phenotypes can be defined by analyzing a large group of patients. The fact that only one Algerian family was linked to chromosome 8 suggests that this is a rare localization even in kindreds with the same ethnic background. Linkage to chromosome 16 was found in 2 clinically diverse Portuguese kindreds, illustrating that this locus is also rare and may correspond to different phenotypes.

Generalized freezing in Hallervorden-Spatz syndrome: case report

We report the case of a female patient who was exhibiting slowly progressive, severe, generalized freezing of voluntary movement and disequilibrium. Brain magnetic resonance imaging showed a very low signal intensity in both pallidal nuclei, with a high signal intensity in the central portion, the so called 'eye-of-the-tiger' sign. Despite the unusual clinical features, we believe that this is a case of Hallervorden-Spatz syndrome, although without neuropathological examination we were unable to confirm the diagnosis with certainty. This case further demonstrates the complex role of the pallidum in voluntary movement.

Intravenous cyclosporine for steroid-refractory attacks of Crohn's disease. Short- and long-term results

A prospective, open trial was conducted to test whether i.v. cyclosporine was effective in the treatment of refractory Crohn's disease. Eight patients with acute steroid-refractory attacks were included. Intravenous cyclosporine, 5 mg/kg/day, was added to ongoing drug therapy. Patients who responded were then switched to oral cyclosporine for a mean 2.6-month period, and steroids were discontinued when possible. Six patients improved, with a mean latency time to onset of improvement of 9 days. Two did not improve, and both underwent urgent operation. On oral cyclosporine, five patients maintained remission and discontinued steroids, whereas one relapsed and underwent surgery. After discontinuation of oral cyclosporine, the five remaining patients relapsed, and two underwent surgery. One reversible episode of hepatobiliary toxicity and one of gastrointestinal intolerance were recorded. We conclude that i.v. cyclosporine effectively and rapidly induces improvement of acute steroid-refractory flare-ups of Crohn's disease, but after discontinuation relapse is to be expected.

Genetic heterogeneity in hypokalemic periodic paralysis (hypoPP)

Hypokalemic periodic paralysis (hypoPP) is an autosomal dominant disorder belonging to a group of muscle diseases known to involve an abnormal function of ion channels. The latter includes hypokalemic and hyperkalemic periodic paralyses, and non-dystrophic myotonias. We recently showed genetic linkage of hypoPP to loci on chromosome 1q31-32, co-localized with the DHP-sensitive calcium channel CACNL1A3. We propose to term this locus hypoPP-1. Using extended haplotypes with new markers located on chromosome 1q31-32, we now report the detailed mapping of hypoPP-1 within a 7 cM interval. Two recombinants between hypoPP-1 and the flanking markers D1S413 and D1S510 should help to reduce further the hypoPP-1 interval. We used this new information to demonstrate that a large family of French origin displaying hypoPP is not genetically linked to hypoPP-1. We excluded genetic linkage over the entire hypoPP-1 interval showing for the first time genetic heterogeneity in hypoPP.

Are the endemic motor neuron diseases of Guam really disappearing?

Death certificates were reviewed to observe trends in the number of persons on Guam reported to have chronic degenerative motor neuron diseases (amyotrophic lateral sclerosis, parkinsonism-dementia or Parkinson's disease) at the time of death. Additional data, including age and race of the deceased and the name of the certifying physician were also collected. The number of persons having been diagnosed with amyotrophic lateral sclerosis is apparently decreasing while their mean age is increasing suggesting that the etiologic agents or factors causing this disease are less prevalent on Guam today than they have been in the past. Trends with regard to parkinsonism-dementia and Parkinson's disease are less clear.