High burden of neurological disease in the older general population: results from the Canadian Longitudinal Study on Aging.

BACKGROUND AND PURPOSE: Our objective was to study the association between the presence of a neurological disease and the comorbidity burden as well as healthcare utilization (HCU). METHODS: Using baseline data from the Canadian Longitudinal Study on Aging (CLSA), we examined the burden of five neurological conditions. The CLSA is a population-based study of approximately 50 000 individuals, aged 45-85 years at baseline. We used multivariable Poisson regression to identify correlates of comorbidity burden and HCU. RESULTS: The lifetime prevalence of five neurological diseases is presented: epilepsy, Parkinson's disease/parkinsonism, stroke/transient ischaemic attack, multiple sclerosis and migraine. We found the somatic and psychiatric comorbidity burden to be higher in those individuals with a neurological disease (an 18-45% mean increase in the number of chronic conditions) as compared with the comparison group without a neurological disease, except for Parkinson's disease/parkinsonism. The presence of a neurological disease was associated with only a modest increase in the probability of visiting a general practitioner but was associated with a greatly increased probability of visiting a medical specialist (up to 68% more likely) or an emergency department (up to 79% more likely) and an overnight hospitalization (up to 108% more likely). CONCLUSIONS: We found striking associations between our neurological diseases and increased comorbidity burdens and HCU. These findings are important for informing public policy planning as well as driving avenues for future research. The present study established the CLSA as an important research platform for the study of neurological conditions in an aging general population.

Does low socioeconomic status in early life protect against multiple sclerosis? A multinational, case-control study.

BACKGROUND AND PURPOSE: The findings from existing research on the association between socioeconomic status (SES) and multiple sclerosis (MS) are inconsistent. Most previous studies are limited to one country and do not adequately adjust for other risk factors for the disease. METHODS: The association between SES and MS was examined using data from the multinational Environmental Risk Factors in Multiple Sclerosis (EnvIMS) case-control study, comprising 2144 cases and 3859 controls from Norway, Canada and Italy. Multiple logistic regression was used to estimate the odds ratios and 95% confidence intervals for the association between early life SES, measured by parental educational level, and MS. Analyses were adjusted for age, sex, sunlight exposure, history of infectious mononucleosis, smoking, obesity and family size. RESULTS: Relative to those whose parents had primary school education or below, the adjusted odds ratio (95% confidence interval) for MS amongst individuals with university-educated parents, and the P value for trend across education levels, were 1.45 (1.03-2.05) in Canada (P for trend 0.030), 1.09 (0.85-1.39) in Norway (P for trend 0.395) and 0.65 (0.39-1.07) in Italy (P for trend 0.158). CONCLUSION: There is no consistent association between parental SES and MS risk in Norway, Canada and Italy, with a protective effect of low SES only found in Canada.

The diagnostic accuracy of routine electroencephalography after a first unprovoked seizure.

The clinical utility of routine electroencephalography (EEG) after a first unprovoked seizure remains uncertain. Its diagnostic accuracy in identifying adults and children with new onset epilepsy was examined. A systematic review and meta-analysis of studies examining individuals who underwent routine EEG after a first unprovoked seizure and were followed for seizure recurrence for at least 1 year was performed. A 'positive' test was defined by the presence of epileptiform discharges (ED). Pooled sensitivity and specificity estimates were calculated using a bivariate random effects regression model. In all, 3096 records were reviewed, from which 15 studies were extracted with a total of 1799 participants. Amongst adult studies, the sensitivity and specificity (95% confidence interval) of routine EEG were 17.3% (7.9, 33.8) and 94.7% (73.7, 99.1), respectively. Amongst child studies, the pooled sensitivity and specificity were 57.8% (49.7, 65.6) and 69.6% (57.5, 79.5), respectively. Based upon our positive likelihood ratios, and assuming a pre-test probability of 50%, an adult with ED on routine EEG after a first unprovoked seizure has a 77% probability of having a second seizure, whilst a child with similar findings has a 66% probability. Further studies are required to examine the impact of patient characteristics and EEG features on the diagnostic accuracy of routine EEG for new onset epilepsy.

Comorbidity is associated with pain-related activity limitations in multiple sclerosis.

BACKGROUND: Comorbidities are common in multiple sclerosis (MS). The high prevalence of pain in MS is well-established but the influence of comorbidities on pain, specifically, pain-related interference in activity is not. OBJECTIVE: To examine the relationship between comorbidity and pain in MS. METHODS: We recruited 949 consecutive patients with definite MS from four Canadian centres. Participants completed the Health Utilities Index (HUI-Mark III) and a validated comorbidity questionnaire at 3 visits over 2 years. The HUI's pain scale was dichotomized into two groups: those with/without pain that disrupts normal activities. We used logistic regression to assess the association of pain with each comorbidity individually at baseline and over time. RESULTS: The incidence of disruptive pain over two years was 31.1 per 100 persons. Fibromyalgia, rheumatoid arthritis, irritable bowel syndrome, migraine, chronic lung disease, depression, anxiety, hypertension, and hypercholesterolemia were associated with disruptive pain (p<0.006). Individual-level effects on the presence of worsening pain were seen for chronic obstructive pulmonary disease (odds ratio [OR]: 1.50 95% CI: 1.08-2.09), anxiety (OR: 1.49 95% CI: 1.07-2.08), and autoimmune thyroid disease (OR: 1.40 95% CI: 1.00-1.97). CONCLUSION: Comorbidity is associated with pain in persons with MS. Closer examination of these associations may provide guidance for better management of this disabling symptom in MS.

Is high socioeconomic status a risk factor for multiple sclerosis? A systematic review.

High socioeconomic status (SES) is generally associated with better health outcomes, but some research has linked it with an increased risk of multiple sclerosis (MS). The evidence for this association is inconsistent and has not previously been systematically reviewed. A systematic review of cohort and case-control studies in any language was conducted looking at the association between MS and SES. MEDLINE and EMBASE were searched for articles in all languages published up until 23 August 2013. Twenty-one studies from 13 countries were included in the review. Heterogeneity of study settings precluded carrying out a meta-analysis, and a qualitative synthesis was performed instead. Five studies, all from more unequal countries, reported an association between high SES and MS. Thirteen studies reported no evidence of an association, and three studies reported an association with low SES. These 16 studies largely came from more egalitarian countries. The evidence for an association between high SES and increased MS risk is inconsistent but with some indication of a stronger effect in countries and time periods with higher inequality. Firm conclusions are hampered by the failure of most studies to control for other important risk factors for MS.

Performance of administrative case definitions for comorbidity in multiple sclerosis in Manitoba and Nova Scotia.

INTRODUCTION: As the population ages and the prevalence of comorbid conditions increases, the need for feasible, validated methods of comorbidity surveillance in chronic diseases such as multiple sclerosis (MS) increases. METHODS: Using kappa (k) statistics, we evaluated the performance of administrative case definitions for comorbidities commonly observed in MS by comparing agreement between Manitoba (MB) administrative data and self-report (n = 606) and Nova Scotia (NS) administrative data and self-report (n = 1923). RESULTS: Agreement between the administrative definitions and self-report was substantial for hypertension (k = 0.69 [NS], 0.76 [MB]) and diabetes (k = 0.70 [NS], 0.66 [MB]); moderate for hyperlipidemia (k = 0.53 [NS], 0.51 [MB]) and heart disease (k = 0.42 [NS], 0.51 [MB]) and fair for anxiety (k = 0.27 [NS], 0.26 [MB]). In NS, agreement was substantial for inflammatory bowel disease (k = 0.71) and moderate for epilepsy (k = 0.48). CONCLUSION: Administrative definitions for commonly observed comorbidities in MS performed well in 2 distinct jurisdictions. This suggests that they could be used more broadly across Canada and in national studies.

TITRE: Performance des définitions administratives de cas pour les affections concomitantes de la sclérose en plaques au Manitoba et en Nouvelle-Écosse. INTRODUCTION: Au fur et à mesure du vieillissement de la population et de l'augmentation de la prévalence d'affections concomitantes, le recours à des méthodes fiables et efficaces de surveillance des affections concomitantes de maladies chroniques telles que la sclérose en plaques (SP) s'avère de plus en plus nécessaire. MÉTHODOLOGIE: Nous avons évalué, au moyen de la statistique kappa (k), la performance des définitions administratives de cas pour les affections concomitantes fréquemment observées en lien avec la SP en comparant les concordances entre les données administratives et les données provenant d'autodéclarations au Manitoba (MB) (n = 606) et en Nouvelle-Écosse (NS) (n = 1 923). RÉSULTATS: Les concordances entre les définitions administratives et les autodéclarations étaient bonnes pour l'hypertension (k = 0,69 [NS] et 0,76 [MB]) et le diabète (k = 0,70 [NS] et 0,66 [MB]), modérées pour l'hyperlipidémie (k = 0,53 [NS] et 0,51 [MB]) et la cardiopathie (k = 0,42 [NS] et 0,51 [MB]) et médiocres pour l'anxiété (k = 0,27 [NS] et 0,26 [MB]). La concordance était bonne en Nouvelle-Écosse pour la maladie inflammatoire chronique de l'intestin (k = 0,71) et modérée pour l'épilepsie (k = 0,48). CONCLUSION: Les définitions administratives étaient performantes dans les deux provinces pour plusieurs affections concomitantes fréquemment observées en lien avec la SP. À la lumière de ces résultats, il semble que ces définitions puissent être utilisées plus largement au Canada et dans les études nationales.

MS incidence and prevalence in Africa, Asia, Australia and New Zealand: A systematic review.

OBJECTIVES: Studies of multiple sclerosis (MS) incidence and prevalence from Africa, Asia, Australia and New Zealand are relatively scarce. We systematically reviewed MS incidence and prevalence in these regions including a standardized evaluation of study quality. METHODS: We searched MEDLINE and EMBASE databases for studies of MS prevalence or incidence in Africa, Asia, Australia and New Zealand published in English or French between January 1, 1985 and January 31, 2011. Study quality was assessed using a standardized tool. All steps of the review were performed in duplicate. RESULTS: Of 3925 citations identified, 28 studies met inclusion criteria and 21 of these were from Asia. Quality scores ranged from 1/8 to 8/8; the lowest scores were observed in studies from Asia (median 4/8, IQR 3,6). Prevalence was lowest in South African Blacks (0.22/100,000) and highest amongst Australian-born individuals in Australia (125/100,000). Prevalence increased over time in many countries. MS prevalence increased with increasing latitude only in some regions, and prevalence varied significantly with ethnicity. Eight studies reported incidence, which ranged from 0.67/100,000/year in Taiwan to 3.67/100,00/year in Australia. CONCLUSIONS: This comprehensive study provides an update of MS epidemiology in Africa, Asia, Australia, and New Zealand. Incidence and prevalence were lowest in Africa and Asia and highest in Australia, but many Asian studies were of poor quality. Use of consistent case ascertainment methods, standardized data collection tools, and similar outcomes would all improve study quality and comparability. The underlying basis of observed ethnic differences is an important area for future study.

Restless legs syndrome outside the blood-brain barrier--exacerbation by domperidone in Parkinson's disease.

INTRODUCTION: Models of dopaminergic function in restless legs focus on central dopaminergic neurons. Domperidone, a peripheral dopamine blocker that cannot cross the blood-brain barrier, is commonly used in Parkinson's disease. After encountering a case of restless legs syndrome that dramatically worsened with domperidone, we assessed whether Parkinson's patients may have exacerbation of restless legs with domperidone. METHODS: From two Parkinson's disease cohorts, we assessed restless legs prevalence according to standard criteria, in patients taking vs. not taking domperidone. Regression analysis was performed, adjusting for age, sex, disease duration, UPDRS, dopaminergic medications and other medications. RESULTS: One hundred eighty four patients were assessed, of whom 46 (25%) had restless legs. Thirteen out of twenty seven (48%) patients on domperidone had restless legs compared to 33/157 (21%) without (p = 0.010). Other medications were not associated with restless legs. CONCLUSION: This unexpected finding suggests that dopaminergic neurons outside of the blood-brain barrier may be important in restless legs syndrome pathophysiology.

Environmental risk factors for REM sleep behavior disorder: a multicenter case-control study.

OBJECTIVE: Idiopathic REM sleep behavior disorder is a parasomnia characterized by dream enactment and is commonly a prediagnostic sign of parkinsonism and dementia. Since risk factors have not been defined, we initiated a multicenter case-control study to assess environmental and lifestyle risk factors for REM sleep behavior disorder. METHODS: Cases were patients with idiopathic REM sleep behavior disorder who were free of dementia and parkinsonism, recruited from 13 International REM Sleep Behavior Disorder Study Group centers. Controls were matched according to age and sex. Potential environmental and lifestyle risk factors were assessed via standardized questionnaire. Unconditional logistic regression adjusting for age, sex, and center was conducted to investigate the environmental factors. RESULTS: A total of 694 participants (347 patients, 347 controls) were recruited. Among cases, mean age was 67.7 ± 9.6 years and 81.0% were male. Cases were more likely to smoke (ever smokers = 64.0% vs 55.5%, adjusted odds ratio [OR] = 1.43, p = 0.028). Caffeine and alcohol use were not different between cases and controls. Cases were more likely to report previous head injury (19.3% vs 12.7%, OR = 1.59, p = 0.037). Cases had fewer years of formal schooling (11.1 ± 4.4 years vs 12.7 ± 4.3, p < 0.001), and were more likely to report having worked as farmers (19.7% vs 12.5% OR = 1.67, p = 0.022) with borderline increase in welding (17.8% vs 12.1%, OR = 1.53, p = 0.063). Previous occupational pesticide exposure was more prevalent in cases than controls (11.8% vs 6.1%, OR = 2.16, p = 0.008). CONCLUSIONS: Smoking, head injury, pesticide exposure, and farming are potential risk factors for idiopathic REM sleep behavior disorder.

Treatment comfort of adult neurologists in childhood onset conditions.

BACKGROUND: The majority of children with chronic neurodevelopmental disabilities are surviving to adulthood. Our goal was to assess how prepared and comfortable adult neurologists are in treating young adults with childhood onset chronic neurological conditions and evaluate the difficulty pediatric neurologists experience when transferring these patients to adult care. METHODS: We conducted a cross-sectional study using two postal surveys of all pediatric and adult neurologists in the province of Quebec, Canada. RESULTS: The response rate was 51.5%, with 119 neurologists completing the survey. Half of neurologists agreed that adult neurologists may not have adequate training in childhood onset disorders to prepare them to manage the disorders in adulthood, and 60% of pediatric neurologists reported having difficulty finding an adult provider for their patients. Adult neurologists were least comfortable treating patients with autism, chromosomal or metabolic disorders, and cognitive or behavioral disorders. CONCLUSION: Almost half of those surveyed believed that adult neurologists are not adequately trained to care for this growing patient population. Improving treatment comfort and knowledge among adult neurologists in childhood onset chronic neurological conditions may smooth the transition of these young adults from pediatric to adult care.

Validation of the non-motor symptoms questionnaire (NMS-Quest).

BACKGROUND: Although non-motor manifestations of Parkinson's disease are common and can cause severe disability, they are often under-recognized, leading to missed treatment opportunities. Screening tools for non-motor symptoms are urgently needed. Recently a 30-item screening Non Motor Symptoms Questionnaire was developed. Although some psychometric properties have been evaluated, sensitivity and specificity of the questionnaire have not been systematically assessed. METHODS: Parkinson patients completed Non Motor Symptoms Questionnaire, then underwent a gold-standard clinical evaluation of non-motor symptoms and signs that included extensive standardized questionnaires, cognitive/behavioural assessment, and neurological examination to determine whether each manifestation was present or absent. The sensitivity and specificity of each non-motor symptom, in relation to the gold-standard were estimated. RESULTS: For the 70 participants, the mean age was 66.7+/-9.3, 64% were men, and disease duration was 3.8+/-2.8 years. From the gold-standard evaluation, the prevalence of non-motor manifestations ranged from 8.7% (hallucinations) to 78.3% (nocturia). The mean sensitivity of all Non Motor Symptoms was 63.4%. This varied considerably among different manifestations, ranging from 24% (sleepiness, hyposmia) to 100% (diplopia). By restricting analysis to clinically significant non-motor problems (i.e. those serious enough to warrant treatment), the mean sensitivity increased to 71.8%. The specificity for most items was high, with an overall mean specificity of 88.5%. CONCLUSIONS: For many non-motor manifestations Non Motor Symptoms Questionnaire is an effective screen; however, for manifestations such as somnolence, olfactory loss and apathy, sensitivity is suboptimal. Overall, this questionnaire can be a useful clinical tool for screening non-motor problems in an office setting.

Harmonization: a methodology for advancing research in multiple sclerosis.

Decreasing research funding is in conflict with the increasing need to conduct large studies to examine rare risk factors and interactions between risk factors. As a result, investigators are searching for strategies to stretch research funds and to design studies that will maximize investments already made. Multiple sclerosis (MS) is generally accepted as a multifactorial disease, and the assessment of interactions between risk factors and the desire to assess risk factors within particular sub-groups requires a large number of participants. Harmonization is a methodology that may help address this problem. Harmonization is a methodological approach that aims to systematize the process of combining individual data that are collected in several observational studies. Combining data will increase sample size, but the quality of the harmonized result is only as high as the quality of the individual studies and the comparability of the constructs measured. In this short report, we introduce the concept of harmonization and provide examples where harmonization may be advantageous in MS research.

A questionnaire for multinational case-control studies of environmental risk factors in multiple sclerosis (EnvIMS-Q).

OBJECTIVES: The increasing incidence of multiple sclerosis (MS) worldwide, especially in women, points to the crucial role of environmental and lifestyle risk factors in determining the disease occurrence. An international multicentre case-control study of Environmental Risk Factors In Multiple Sclerosis (EnvIMS) has been launched in Norway, Sweden, Italy, Serbia and Canada, aimed to examine MS environmental risk factors in a large study population and disclose reciprocal interactions. To ensure equivalent methodology in detecting age-related past exposures in individuals with and without MS across the study sites, a new questionnaire (EnvIMS-Q) is presented. MATERIALS AND METHODS: EnvIMS-Q builds on previously developed guidelines for epidemiological studies in MS and is a 6-page self-administered postal questionnaire. Participants are de-identified through the use of a numerical code. Its content is identical for cases and controls including 'core' and population-specific questions as proxies for vitamin D exposure (sun exposure, dietary habits and supplementation), childhood infections (including infectious mononucleosis) and cigarette smoking. Information on possible confounders or effect modifiers is also obtained. EnvIMS-Q was initially drafted in English and subsequently translated into Italian, Serbian, Norwegian, Swedish and French-Canadian. EnvIMS-Q has been tested for acceptability, feasibility and reliability. RESULTS AND CONCLUSIONS: EnvIMS-Q has shown cross-cultural feasibility, acceptability and reliability in both patients with MS and healthy subjects from all sites. EnvIMS-Q is an efficient tool to ensure proper assessment of age-specific exposure to environmental factors in large multinational population-based case-control studies of MS risk factors.

Quality of life during the course of cancer treatment in older newly diagnosed patients. Results of a prospective pilot study.

BACKGROUND: The aim of this prospective study was to report the quality of life (QoL) of older cancer patients during the first year after diagnosis and factors influencing QoL. PATIENTS AND METHODS: Newly diagnosed patients aged ≥65 years were recruited for a pilot prospective cohort study at the Jewish General Hospital, Montreal, Canada. Participants were interviewed at baseline, and at 1.5, 3, 4.5, 6, and 12 months. QoL was assessed at each interview using the European Organization for the Research and Treatment of Cancer Quality of Life Core Questionnaire with 30 items. Logistic regression was conducted to determine which sociodemographic, health, and functional status characteristics were associated with decline in global health status/QoL between baseline and 12-month follow-up. RESULTS: There were 112 participants at baseline (response rate 72%), median age of 74.1, and 70% were women. Between baseline and 12-month follow-up (n=78), 18 participants (23.1%) declined ≥10 points in global health status/QoL, while 34 participants (43.6%) remained stable and 23 participants (33.3%) improved ≥10 points. None of the sociodemographic, health, and functional status variables were associated with decline in logistic regression analyses. CONCLUSION: Almost 25% of older adults experienced clinically relevant decline in their QoL. Further research is needed on which factors influence decline in QoL in older adults.

Does frailty predict hospitalization, emergency department visits, and visits to the general practitioner in older newly-diagnosed cancer patients? Results of a prospective pilot study.

Research on the use of health care by older newly-diagnosed cancer patients is sparse. We investigated whether frailty predicts hospitalization, emergency department (ED) and general practitioner (GP) visits in older cancer patients in a prospective pilot study. Newly-diagnosed cancer patients aged 65 years and over were recruited in the Segal Cancer Centre, Jewish General Hospital, Montreal, Canada. One hundred ten patients participated, mean age 74.1, 70% women. During 1 year follow-up, 52 patients (47.3%) had cancer-related hospitalizations, 23 patients (20.9%) had ED visit and 17 patients (15.5%) had GP visit. No frailty marker predicted hospitalization or visits to the GP. Cognitive impairment suspicion was the only frailty marker that predicted ED visits (odds ratio 4.97; 95%CI 1.14-21.69). Although health care use was considerable in this sample, most frailty markers were not associated with health care use in this pilot study.

Clinical experience of cancer specialists and geriatricians involved in cancer care of older patients: A qualitative study.

INTRODUCTION: Cancer is an important health problem in older persons. The aim of this study was to explore how cancer specialists and geriatricians manage the treatment of older patients with cancer. METHODS: Interviews using semi-structured open-ended questions. SAMPLE: physicians working in oncology and geriatric medicine at McGill affiliated hospitals. ANALYSIS: Grounded-theory approach. RESULTS: 24 cancer specialists and 17 geriatricians participated. There was considerable variability with regard to assessment, treatment plan, and follow-up care and little collaboration between both specialists. The cancer specialists have more older cancer patients in their practice and collaborate with geriatricians mostly to deal with complications of cancer treatment. However, both groups of specialists expressed a desire to collaborate more and had similar research priorities. CONCLUSIONS: There was considerable variability in the management of older patients with cancer. Care for older patients with cancer might be improved by more collaboration between cancer specialists and geriatricians.

Incidence and prevalence of amyotrophic lateral sclerosis in Canada: a systematic review of the literature.

BACKGROUND: Amyotrophic lateral sclerosis (ALS) is a fatal progressive neurodegenerative disease of unknown etiology. Although known to be rare, precise information on the frequency of ALS is essential to anticipate future demands on health resources and as baseline information for epidemiological studies. As part of a new ALS epidemiological initiative in Canada, we conducted a systematic review of published incidence and prevalence research in Canada. METHODS: Electronic searches and bibliographic reviews of pertinent publications were conducted. RESULTS: We identified 6 published studies from 4 Canadian provinces conducted between 1974 and 2004; 2 were available only as abstracts. Reported annual incidence rates were similar and study quality was generally good, but there was insufficient detail to adequately assess the methodological quality of 3 of the studies. The most recent studies reported an annual ALS age-adjusted incidence of 2.13 per 100,000 in Nova Scotia (2003-2004) and a crude mean annual incidence of 2.4 per 100,000 in Newfoundland and Labrador (2000-2004). CONCLUSIONS: There are limited data on the frequency of ALS in Canada. We found no studies from 6 of the Canadian provinces or from the territories. Future research is needed to estimate the frequency of occurrence of ALS in Canada.

Environmental risk factors in multiple sclerosis.

OBJECTIVES: Multiple sclerosis (MS) likely results from an interaction between genetic and exogenous factors. While genetics shapes the overall population MS susceptibility, observed epidemiological patterns strongly suggest a role for the environment in disease initiation and modulation. RESULTS: Findings from studies on seasonality in MS patients' birth, disease onset and exacerbations, as well as apparent temporal trends in incidence and gender ratio support an influential effect of viruses, metabolic and lifestyle factors on MS risk. Epstein-Barr virus, vitamin D status, and smoking are factors that may explain such epidemiological patterns. CONCLUSIONS: Further epidemiological investigations are encouraged and opportunities to use data from existing cohort studies as well as the design of new studies should be pursued. In particular, the development of new large multicentre population-based case-control studies which incorporate the study of the role of environment and genetics, including epigenetic mechanisms, in determining MS risk is proposed.

Social networks and self-rated health in two French-speaking Canadian community dwelling populations over 65.

The objective was to evaluate the associations between older persons' health status and their social integration and social networks (family, children, friends and community), in two French-speaking, Canadian community dwelling populations aged 65 years and over, using the conceptual framework proposed by Berkman and Thomas. Data were taken from two 1995 surveys conducted in the city of Moncton (n = 1518) and the Montreal neighbourhood of Hochelaga-Maisonneuve (n = 1500). Social engagement (a cumulative index of social activities), networks consisting of friends, family and children and social support were measured using validated scales. Multiple logistic regressions based on structured inclusion of potentially mediating variables were fitted to estimate the associations between health status and social networks. Self-rated health was better for those with a high level of social integration and a strong network of friends in both locations. In addition, in Hochelaga-Maisonneuve family and children networks were positively associated with good health, though the effect of friend networks was attenuated in the presence of disability, good social support from children was associated with good health. Age, sex and education were included as antecedent variables; smoking, alcohol consumption, exercise, locus of control and depressive symptoms were considered intermediary variables between social networks and health. In conclusion, social networks, integration and support demonstrated unique positive associations with health. The nature of these associations may vary between populations and cultures.

Human herpes virus 6 and multiple sclerosis.

OBJECTIVES: To systematically review the published evidence for a relationship between human herpes virus 6 (HHV-6) and multiple sclerosis (MS). MATERIALS AND METHODS: The medical literature was searched using MEDLINE and the Cochrane database. Retrieved studies are presented according to the experimental technique(s) used. The studies are rated for quality using a priori defined criteria. RESULTS: Twenty-eight studies were retrieved. A total of 12 different experimental techniques were used. Four of these techniques provided evidence for a relationship between HHV-6 and MS, but none were able to show a causative relationship. CONCLUSIONS: The available literature provides some support for a relationship between HHV-6 and MS. The limitations of the available studies and directions for future research are discussed.