Mortality and morbidity peaks modeling: An extreme value theory approach.

Hospitalizations and deaths belong to the most studied health variables in public health. Those variables are usually analyzed through mean events and trends, based on the whole dataset. However, this approach is not appropriate to comprehend health outcome peaks which are unusual events that strongly impact the health care network (e.g. overflow in hospital emergency rooms). Peaks can also be of interest in etiological research, for instance when analyzing relationships with extreme exposures (meteorological conditions, air pollution, social stress, etc.). Therefore, this paper aims at modeling health variables exclusively through the peaks, which is rarely done except over short periods. Establishing a rigorous and general methodology to identify peaks is another goal of this study. To this end, the extreme value theory appears adequate with statistical tools for selecting and modeling peaks. Selection and analysis for deaths and hospitalizations peaks using extreme value theory have not been applied in public health yet. Therefore, this study also has an exploratory goal. A declustering procedure is applied to the raw data in order to meet extreme value theory requirements. The application is done on hospitalization and death peaks for cardiovascular diseases, in the Montreal and Quebec metropolitan communities (Canada) for the period 1981-2011. The peak return levels are obtained from the modeling and can be useful in hospital management or planning future capacity needs for health care facilities, for example. This paper focuses on one class of diseases in two cities, but the methodology can be applied to any other health peaks series anywhere, as it is data driven.

Exposure of young children to household water lead in the Montreal area (Canada): the potential influence of winter-to-summer changes in water lead levels on children's blood lead concentration.

Drinking water represents a potential source of lead exposure. The purpose of the present study was to estimate the magnitude of winter-to-summer changes in household water lead levels (WLLs), and to predict the impact of these variations on BLLs in young children. A study was conducted from September, 2009 to March, 2010 in 305 homes, with a follow-up survey carried out from June to September 2011 in a subsample of 100 homes randomly selected. The first 1-L sample was drawn after 5 min of flushing, followed by a further 4 consecutive 1-L samples after 30 min of stagnation. Non-linear regression and general linear mixed models were used for modelling seasonal effects on WLL. The batchrun mode of Integrated Exposure Uptake Biokinetic (IEUBK) model was used to predict the impact of changes in WLL on children's blood lead levels (BLLs). The magnitude of winter-to-summer changes in average concentrations of lead corresponded to 6.55 µg/L in homes served by lead service lines (LSL+ homes) and merely 0.30 µg/L in homes without lead service lines. For stagnant samples, the value reached 10.55 µg/L in 'LSL+ homes' and remained very low (0.36 µg/L) in 'LSL- homes'. The change in the probability of BLLs ≥5 µg/dL due to winter-to-summer changes in WLL was increased from <5% (in winter) to about 20% (in summer) in children aged 0.5-2 years. The likelihood of having BLLs ≥5 µg/dL in young children during warm months was reduced by at least 40% by flushing tap-water.

[Benzodiazepine dependence and the risk of depression and anxiety disorders: seniors' health study]. / La dépendance aux benzodiazépines et le risque de troubles anxieux et de dépression : étude sur la santé des aînés.

AIM OF THE STUDY: The objective of this study is to examine the relationship between benzodiazepine dependence and anxiety disorders and depression in people aged 65 years and over. We referred to the data from the study on the health of seniors, a survey of a representative sample of 707 benzodiazepine users living in the community in Quebec, Canada. Benzodiazepine dependence, anxiety disorders and depression were measured using self-reported questionnaires based on the criteria of the Diagnostic and Statistical Manual of Mental Disorders, fourth revised edition. RESULTS: Seniors have consumed an average daily dose of 6.1±7.6mg diazepam equivalent to an average of 205±130 days. The prevalence of benzodiazepine dependence has been estimated at 9.5%. This dependence increases the risk of minor depression for females (relative risk [RR]=4.36, confidence interval 95% [95% CI]=1.19 to 15.99). CONCLUSION: The results of this study suggest that the use of benzodiazepines is far from being optimal among seniors in Quebec. The proportion of seniors who develop an addiction is important. The results illustrate the need to develop and implement programs to improve the quality of benzodiazepine use among this population.

Is marine mammal fat or fish intake most strongly associated with omega-3 blood levels among the Nunavik Inuit?

Here we determined the relationship between red blood cell (RBC) omega-3 (n-3) long-chain polyunsaturated fatty acids (LC-PUFAs) and usual dietary marine food product intake among 630 Nunavik Inuit adults. Marine food product intake was determined by a food frequency questionnaire (FFQ) and fatty acids were quantified in RBC membranes. Multiple linear regression was undertaken to determine the relationship between marine food product intake and RBC n-3 LC-PUFAs (dependent variable). Mean RBC n-3 LC-PUFA level was 9.16 ± 0.11% [SEM]. The highest correlations noted with RBC n-3 LC-PUFAs were for marine mammal fat (r(s)=0.41, P<0.0001) and fish (r(s)=0.35, P<0.0001). Age, total marine mammal fat and fish intakes were the variables that contributed the most to predicted RBC n-3 LC-PUFAs and explained 34%, 15% and 5%, respectively, of its variances. Our study indicates that marine mammal fat intake is more important than fish in accounting for RBC n-3 LC-PUFA levels among the Nunavik Inuit.

Impact of diabetes and gender on survival after acute myocardial infarction in the Province of Quebec, Canada--a population-based study.

AIMS: To examine the impact of diabetes, gender and their interaction on 30-day, 1-year and 5-year post-acute myocardial infarction (AMI) mortality in three age groups (20-64, 65-74 and > or = 75 years). METHODS: Retrospective analysis including 23 700 patients aged > or = 20 years (22% with diabetes) admitted to hospital for a first AMI in any hospital in the Province of Quebec, Canada, between April 1995 and March 1997. Administrative databases were used to identify patients and assess outcomes. RESULTS: Regarding 30-day mortality, there was non-significant interaction between diabetes and gender. Women aged < 75 years had, independently of diabetes status, at least a 38% (P < 0.05) higher mortality than their male counterparts after adjustment for socio-economic status and co-morbid conditions. Gender difference disappeared, however, after controlling for in-hospital complications. Regarding 1-year mortality (31-365 days), there was no significant gender disparity for all age groups. During the 5-year follow-up, no gender differences were seen in any age group, except for younger (< 65 years) women with diabetes, who had a 52% (P = 0.004) higher mortality than men after controlling for co-variables. This female disadvantage was demonstrated by a significant interaction between diabetes and gender in patients aged < 65 years (P = 0.009). CONCLUSIONS: The higher 30-day mortality post-AMI in younger (20-64 years) and middle-aged (65-74 years) women compared with men was not influenced by diabetes status. However, during the 5-year follow-up, the similar gender mortality observed in patients without diabetes seemed to disappear in younger patients with diabetes, which may be explained by the deleterious, long-term, post-AMI impact of diabetes in younger women.

Effectiveness of a participative intervention on psychosocial work factors to prevent mental health problems in a hospital setting.

OBJECTIVES: To assess the effectiveness of a workplace intervention aimed at reducing adverse psychosocial work factors (psychological demands, decision latitude, social support, and effort-reward imbalance) and mental health problems among care providers. METHODS: A quasi-experimental design with a control group was used. Pre-intervention (71% response rate), and one-year post-intervention measures (69% response rate) were collected by telephone interviews. RESULTS: One year after the intervention, there was a reduction of several adverse psychosocial factors in the experimental group, whereas no such reduction was found in the control group. However, there was a significant deterioration of decision latitude and social support from supervisors in both experimental and control groups. There was also a significant reduction in sleeping problems and work related burnout in the experimental hospital, whereas only sleeping problems decreased in the control group while both client related and personal burnout increased in this hospital. The comparison between the experimental and control groups, after adjusting for pre-intervention measures, showed a significant difference in the means of all psychosocial factors except decision latitude. All other factors were better in the experimental group. CONCLUSION: Results suggest positive effects of the intervention, even though only 12 months have passed since the beginning of the intervention. Follow up at 36 months is necessary to evaluate whether observed effects are maintained over time. In light of these results, we believe that continuing the participative process in the experimental hospital will foster the achievement of a more important reduction of adverse psychosocial factors at work. It is expected that the intensity of the intervention will be directly related to its beneficial effects. Long term effects will however depend on the willingness of management and of staff to appropriate the process of identifying what contributes to adverse psychosocial factors at work and to adopt means to reduce them.