Socio-economic disparities in preterm birth: causal pathways and mechanisms.

Preterm birth is the leading cause of infant mortality in industrialised societies. Its incidence is greatly increased among the socially disadvantaged, but the reasons for this excess are unclear and have been relatively unexplored. We hypothesise two distinct sets of causal pathways and mechanisms that may explain social disparities in preterm birth. The first set involves chronic and acute psychosocial stressors, psychological distress caused by those stressors, increased secretion of placental corticotropin releasing hormone (CRH), changes in sexual behaviours or enhanced susceptibility to bacterial vaginosis and chorioamnionitis, cigarette smoking or cocaine use, and decidual vasculopathy. The second hypothesised pathway is a gene-environment interaction based on a highly prevalent mutation in the gene for methylenetetrahydrofolate reductase (MTHFR), combined with low folate intake from the diet and from prenatal vitamin supplements, consequent hyperhomocysteinemia, and decidual vasculopathy. We propose to test these hypothesised pathways and mechanisms in a nested case-control study within a prospectively recruited and followed cohort of pregnant women with singleton pregnancies who deliver at one of four Montreal hospitals that serve an ethnically and socio-economically diverse population. Following recruitment during the late first or early second trimester, participating women are seen at 24-26 weeks, when a research nurse obtains a detailed medical and obstetric history; administers several scales to assess chronic and acute stressors and psychological function; obtains blood samples for CRH, red blood cell and plasma folate, homocysteine, and DNA for the MTHFR mutation; and performs a digital and speculum examination to measure cervical length and vaginal pH and to obtain swabs for bacterial vaginosis and fetal fibronectin. After delivery, each case (delivery at < 37 completed weeks following spontaneous onset of labour or prelabour rupture of membranes) and two controls are selected for placental pathological examination, hair analysis of cotinine, cocaine, and benzoylecgonine, and analysis of stored blood and vaginal specimens. Statistical analysis will be based on multiple logistic regression and structural equation modelling, with sequential construction of models of potential aetiological determinants and covariates to test the hypothesised causal pathways and mechanisms. The research we propose should improve understanding of the factors and processes that mediate social disparities in preterm birth. This improved understanding should help not only in developing strategies to reduce the disparities but also in suggesting preventive interventions applicable across the entire socio-economic spectrum.

Sexual behaviour, condom use and HIV risk situations in the general population of Quebec.

We conducted 3501 telephone interviews to determine the sexual and protective behaviours of the general population in Quebec. Among the 858 respondents who had had at least one occasional partner during the last 5 years, 25.4% had had at least one occasional partner who refused to use a condom. More women had had an occasional partner who had refused than men (29.8% vs 21.1%, P<0.001) and fewer women than men succeeded in negotiating condom use, but more of these women decided not to have sexual relations. The frequency of condom use during the last sexual relation changes if the partner is a regular cohabiting partner (12.5%), a regular non-co-habiting partner (42.2%) or an occasional partner (70.8%). Our study provides important information for the development of prevention programmes for the heterosexual population and demonstrates the importance of the type of relationship maintained by the partners on the sexual behaviours.

Impact of rhinosinusitis in health care delivery: the Quebec experience.

OBJECTIVE: Rhinosinusitis is a common disease affecting 135 per 1,000 population. The cost and the impact on quality of life of this disease are considerable. Health care delivery for a particular disease is evaluated through the health impact of the disease, outcomes of treatments, and their costs. This article reviews our experience with rhinosinusitis and its impact on health, as measured using a generic quality of life instrument, the Medical Outcome Study 36-Item Short-Form Health Survey (SF-36), in a selected patient population. Outcomes of treatments will be introduced, and the economic impact of chronic rhinosinusitis based on a U.S. study will be discussed. MATERIAL AND METHODS: One hundred and ten patients (divided into three subgroups: recurrent acute rhinosinusitis, chronic rhinosinusitis, and nasal polyposis) completed the SF-36 survey on the day of the diagnostic visit in the outpatient sinus clinics of two hospitals. RESULTS: The scores of the SF-36, in chronic rhinosinusitis, are compared with the normative values of a healthy U.S. population showing statistically significant differences in seven of eight domains. A comparison of the scores of chronic rhinosinusitis with a U.S. study on chronic rhinosinusitis shows statistically significant differences in five of eight domains. A comparison of the scores in the three diagnostic subgroups shows a statistical significance in two domains: bodily pain and vitality are more affected in recurrent acute and chronic rhinosinusitis. CONCLUSIONS: Chronic rhinosinusitis affects the quality of life of patients with rhinosinusitis and represents an important health burden. Some differences are noted with the U.S. chronic rhinosinusitis population. Recurrent acute and chronic rhinosinusitis seem to have more impact on vitality and bodily pain than nasal polyposis.

Assessment of neuropsychologic impairments after head injury: interrater reliability and factorial and criterion validity of the Neurobehavioral Rating Scale-Revised.

OBJECTIVE: To study interrater reliability and factorial and criterion validity of the Neurobehavioral Rating Scale-Revised (NRS-R). DESIGN: Validity study on persons with traumatic brain injury (TBI) and test-retest reliability study on a randomly selected subset of patients. Factor analyses, kappa statistics, intraclass correlation coefficients, and Cronbach's alphas were used. SETTING: Inpatients from 15 French hospitals, mainly rehabilitation units. Other recruitment sites included a neurology hospital unit and a psychiatry hospital specifically devoted to TBI rehabilitation. PATIENTS: Two hundred eighty-six TBI patients ages 16 to 70 years (convenience sample). RESULTS: For the reliability study, the average of percentages of agreement among the items was 74.3% and the average of kappa statistics was .40. Factor analyses disclosed a maximum likelihood extraction of 5 correlated factors (F), explaining 42.2% of total variance: (F1) deficits in intentional behavior and in memory, (F2) lowering of emotional state, (F3) emotional and behavioral hyperactivation, (F4) lowering of arousal state and of attention, and (F5) language and speech problems. Results support the criterion validity of the factors. Reliability of the factor scores and internal consistencies of factors were very good. CONCLUSIONS: Results describe some important properties of the NRS-R and, through an understanding of its underlying structure and relationships with the patients' clinical characteristics, contribute to the conceptual framework of neuropsychologic impairments after TBI.

Occupational disability related to back pain: application of a theoretical model of work disability using prospective cohorts of manual workers.

BACKGROUND: A new model of work disability was developed based on the assumption that four different groups of workers are present at the beginning of a prospective epidemiologic study: one group of workers without back pain, and three groups of workers with back pain and a gradient of work disability. The goal of this research was to verify if these groups comprise workers at different levels of risk of occurrence of complete work disability related to back injury. METHODS: Prospective cohorts of manual workers (n=578) were followed for 1 year to document the risk of occurrence of complete disability related to back injury. RESULTS: The results showed that the workers who presented with back pain without work disability at the beginning of the study were at less risk compared to all the other workers in the cohort. Moreover, an effect modification was found between the workers who initially presented with back pain without work disability and a past history of compensation for back injury, adding credence to the non-similarity of these workers to the others. CONCLUSIONS: Based on these results, further studies should focus on improving the knowledge of the characteristics of these workers leading to a better understanding of how to prevent occupational low-back pain.

Comprehensive classification of symptoms and signs reported among 218 patients with acute HIV-1 infection.

Acute HIV-1 illness presents a wide range of clinical manifestations. We assessed a classification and data reduction of clinical features among 218 patients with acute HIV-1 infection enrolled in four prospective seroincidence studies. Factor analysis allows the definition of eight factors based on groups of symptoms and signs: gastrointestinal transit disturbances, weight loss/abdominal pain, lymphadenopathy, myalgia/arthralgia, neurologic features, constitutional and mucocutaneous features, oral candidiasis, and anorexia/pharyngitis. These groups reflected the main target systems involved at the time of acute HIV-1 disease. Grouping of symptoms and signs based on groups of patients is potentially more informative than observations made on individual patients. It might facilitate diagnosis, suggest pathogenic mechanisms and reduce the number of variables for characterizing acute HIV-1 illness.

[Elaboration and validation of a tool to measure psychological well-being: WBMMS]. / Elaboration et validation d'un outil de mesure du bien-être psychologique: l'EMMBEP.

Psychological well-being scales used in epidemiologic surveys usually show high construct validity. The content validation, however, is less convincing since these scales rest on lists of items that reflect the theoretical model of the authors. In this study we present results of the construct and criterion validation of a new Well-Being Manifestations Measure Scale (WBMMS) founded on an initial list of manifestations derived from an original content validation in a general population. It is concluded that national and public health epidemiologic surveys should include both measures of positive and negative mental health.

[Evaluation and validation of a test of psychological distress in a general population in french Quebec]. / Elaboration et validation d'un outil de mesure de la détresse psychologique dans une population non clinique de Québécois francophones.

Psychological distress scales used in epidemiologic surveys usually show high construct validity. The content validation however is less convincing since these scales rest on lists of psychiatric symptoms which are hypothesized as the very content of a psychological distress. This study presents the results of the construct and criterion validation of a new Psychological Distress Manifestations Measure Scale (PDMMS) founded on an initial list of manifestations derived from an original content validation in a general population. Twenty-three items are grouped in four oblique factors with Cronbach's alpha ranging between 0.81 and 0.89. High scores on the scale are correlated with psychoactive drugs consumption, visits to health professionals and self-evaluations of psychological health.

Individual changes in T lymphocyte parameters of old human subjects.

Parameters of peripheral blood T lymphocytes were determined repeatedly (twice, 2-4 weeks apart), in ten old (78 + 5) and compared to nine young (31 + 5) human subjects. Assays included percentage of total, helper, and suppressor, T lymphocytes, and the reaction to PHA stimulation for 24, 48, 72, and 96 h, as assessed by levels of proliferation and IL-2 production. A lower response to PHA was observed in the old as compared to the young, with no significant changes in T cell subsets. A marked variability was noted between the results of the first and second determinations of the response to PHA in each individual. The lack of correlation between the two determinations was more prominent in the old. Unresponsiveness to PHA throughout the incubation period, was noted in two old subjects, but, in only one of the two determinations. This transient unresponsiveness was not accompanied by any changes in their clinical state. Thus, establishments of the immune status of the aged should be based on at least two repeated determinations.

Granulopoiesis in aged people: inverse correlation between bone marrow cellularity and myeloid progenitor cell numbers.

Results of a study on bone marrow (BM) cytology and cellularity, BM granulocytic-macrophage colony formation (GM-CFU-C), peripheral blood (PB) colony stimulating factor (CSF) and serum lysozyme activity in 20 elderly people aged from 64 to 89 are presented. Besides slight iron deficiency anemia, no hematological abnormality was detected. No change in PB and BM differential counts was found as compared to those obtained for normal adults. The BM cellularity and colony incidence were assessed using aliquots of the same specimen. GM-CFU-C frequency ranged from 15 to 156 (average 67.5) per 2 X 10(5) BM cells seeded. The largest number of colonies was observed in hypocellular BM samples (p less than 0.002). The level of serum lysozyme activity for the entire group was significantly higher than that obtained in healthy persons up to the age of 60 (p less than 0.001). The overall results support the notion that in old age, increased proliferation of committed granulopoietic stem cells in hypoplastic areas of the BM, assure normal numbers of mature blood cells in the periphery.