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Biomedical subjects

C Infante-Rivard

Publications and source records attributed to C Infante-Rivard.

At least 55 records · Page 3Linked to original sources
PubMed1997

Use of physician services among family caregivers of elderly persons with dementia.

It is well known that there is an excess of physical and psychological health problems among family caregivers of elderly persons with Alzheimer's disease and other dementias. The objective of this study was to determine whether the higher level of morbidity translates into a higher level of medical care utilization. Data from a previously completed longitudinal study of caregivers for elderly persons with dementia were merged with data on physician visits obtained from the computerized records of the Quebec Health Insurance Board. Utilization of physician care (adjusted for age, sex, number of chronic diseases, and depression) was no higher for family caregivers of elderly patients with Alzheimer's disease and other dementias than for comparable family members of older persons without dementia. The annual cost of physician care was almost identical among caregivers and noncaregivers. However, the pattern of utilization for the two groups was somewhat different: there was a significantly higher frequency of physician utilization among caregivers for services billed by psychiatrists and internal medicine specialists. In multivariate analysis, physician utilization was significantly associated with having more than one chronic condition and with increased age. Future studies should focus on determining whether caregivers neglect their own health care needs as a result of the exigencies of the caregiving role.

Adult↗
PubMed1997

Relapse and short sickness absence for back pain in the six months after return to work.

OBJECTIVES: To measure the incidence of back pain relapse (causing three consecutive days off work on medical advice) and of short sickness absence (less than three consecutive days), and to determine whether the incidence of such events was affected by overall pain and specific pain related to simple daily movements (functional capacity) assessed at discharge. METHODS: A cohort of workers with a first compensated episode of back pain was prospectively followed up from return to work after rehabilitative treatment. Follow up among 230 workers was carried out monthly by phone for a maximum of six months. Crude and adjusted rate ratios (RRs) along with 95% confidence intervals (95% CIs) were estimated with the Cox's proportional hazards model. RESULTS: Within six months of return to work, 29 workers (12.6%) had relapsed, and another 15 workers (6.5%) had a short sickness absence. 50% of relapses had occurred within 42 days of return to work whereas this figure was 28 days for short sickness absence. In a multivariate model that considered pain and clinical variables at discharge only a scale combining all pain variables (specific daily movements as well as the visual analog overall pain scale) contributed to relapse and short sickness absence as the outcome (RR (95% CI)) (1.53 (0.96-2.43)); the same was true in a model considering pain and workers' views on desired changes to work conditions (1.60; 1.08 to 2.36). CONCLUSIONS: Incidence of relapse or short sickness absence in the first six months after return to work was 19.1%. Of all measured prognostic variables (sociodemographic, clinical, workers' views, and pain), only overall pain and pain associated with carrying out simple daily movements were helpful in predicting relapse or short sickness absence.

Absenteeism↗
PubMed1997

Specific IgE-dependent sensitization, atopy, and bronchial hyperresponsiveness in apprentices starting exposure to protein-derived agents.

Atopy, specific IgE sensitization, and bronchial hyperresponsiveness (BHR) were examined in a cohort of 769 apprentices starting career programs in animal health or veterinary medicine (Group 1), pastry making (Group 2), and dental hygiene (Group 3). The hypothesis were that: (1) a proportion of subjects can be "sensitized" although no significant specific occupational exposure has occurred; and (2) there is a relationship between baseline specific sensitization to work-related antigens and host characteristics. Skin tests were administered using 11 common inhalants and specific allergens, including six laboratory animal extracts, three cereal antigens, alpha-amylase, and latex. Methacholine challenge tests were performed. The prevalence of atopy was 54.4% in Group 1, 58.1% in Group 2, and 52.5% in Group 3. Skin reactivity to work-specific proteins was as follows: laboratory animal proteins, 13.8% in Group 1, 14.0% in Group 2, and 15.6% in Group 3. No subject was sensitized to alpha-amylase, whereas 1.2% in Group 1, 5% in Group 2, and 4.1% in Group 3 were sensitized to flour. Five subjects reacted to latex. BHR (PC20 < or = 8 mg/ml) was present in 17.6%, 21.2%, and 14.8% of subjects in Groups 1, 2, and 3, respectively. Specific sensitization was associated with positive skin reactions to common allergens, work-related symptoms, and BHR. These results suggest that students starting career programs with exposure to high-molecular-weight allergens have a low but substantial frequency of specific sensitization to work-related allergens that is related to atopy and BHR.

Adult↗
PubMed1997

Sleep Quality of Former Night-shift Workers.

This study explored the relationship between past night-shift work and present quality of sleep, first by a survey and second with standard laboratory recordings. Nurses (n = 479) working on a day or evening schedule answered a questionnaire about past night-shift work and present quality of sleep. An insomnia index, derived from the questionnaire, was elevated for nurses who had worked more than five nights per month for four to ten years. The index was low for the 13 nurses who had worked more than ten years on night shifts. The sleep of 15 day nurses was recorded in the laboratory. Results showed that a high insomnia index was associated with a high number of awakenings, and that former night-shift workers had a significant reduction in slow-wave sleep, whether or not they had subjective sleep complaints. These results suggest that working at night may have persistent deleterious effects on sleep quality when the experience is long and includes a substantial number of night shifts.

Journal Article↗
PubMed1996

Prognostic factors for return to work after a first compensated episode of back pain.

OBJECTIVES: To determine which factors measured at baseline and during the course of treatment influence time to return to work after a first compensated episode of back pain. METHODS: The design is a treatment inception cohort including 305 compensated workers out of 402 eligible ones presenting at two rehabilitation centres for conventional treatment. Crude and adjusted rate ratios (RRs) along with 95% confidence intervals (95% CIs) were estimated with the Cox's proportional hazards regression. RESULTS: 50% of workers had not returned to work after 112 days of follow up, and 11.3% still had not after 270 days. At the end of the study period (maximum follow up time was 1228 days), 230 workers (75.4%) had returned to work, 6.5% had not, and a similar percentage had retired, gone into vocational training, or returned to school. In the final model stratified for radiating pain during treatment, which was an important prognostic variable, workers between 21 to 30 years of age had a greater chance of returning to work (RR (95% CI) 1.43 (1.04 to 1.98) than those > or = 30. The other factors associated with a greater chance of returning to work were: a diagnosis of sprain or pain upsilon a diagnosis of intervertebral disc disorder (2.20 (1.23-3.91)), < 30 days of waiting between the accident and the beginning of treatment (1.30 (0.96 to 1.77)), a good flexion at baseline (1.52 (1.04 to 2.23)), absence of neurological symptoms during treatment (1.40 (0.98-2.00)), > 24 months of employment in the industry (1.49 (1.10 to 2.03)), working for a public industry upsilon a private one (1.63 (1.21 to 2.19)), and the ability to take unscheduled breaks (1.45 (1.06 to 1.97)). CONCLUSIONS: Even with a first episode of back pain, time to return to work is long and the proportion not returning is high. Return to work as expected is influenced by disease and host characteristics but also by social and work factors. Reinstatement programmes should account for all these factors.

Adult↗
PubMed1996

Diagnostic accuracy of a portable recording device (MESAM IV) in suspected obstructive sleep apnoea.

This study evaluated the accuracy of a portable recording device (MESAM IV) in identifying obstructive sleep apnoea (OSA). The MESAM IV system measures arterial oxygen saturation (Sa,O2), heart rate, snoring sounds and body position, and allows both automatic and manual scoring of the recordings. Nocturnal polysomnography and MESAM IV recordings were performed simultaneously in 150 patients with suspected OSA, and were analysed blindly by a different observer. Patients with an apnoea-hypopnoea index (AHI) greater than or equal to 10 were diagnosed as having OSA. In the evaluation of the discriminatory ability of MESAM IV scores, the cut-off point was set to minimize first the exclusion of truly diseased patients (i.e. false-negative interpretations), and then confirmation of nondiseased subjects (i.e. false-positives). When used as an exclusion test, the portable device reached a sensitivity of 0.98 and a specificity of 0.78; as a confirmation test, these values were 0.69 and 0.97, respectively. These results were achieved with manual scoring, which was superior to automatic scoring. Manual scoring was also better than automatic scoring when OSA was defined according to other threshold values (> or = 5, 15 and 20) for the AHI. The combination of MESAM IV manual scores could reduce the need for diagnostic polysomnography in three quarters of the patients clinically suspected of having obstructive sleep apnoea, substantially reducing costs associated with diagnostic procedures.

Evaluation Studies as Topic↗
PubMed1996

Induced abortion as a risk factor for subsequent fetal loss.

The relation between past induced abortions and subsequent fetal loss is still unclear. We report a case-control study with 331 cases of first spontaneous abortion and 993 controls with no previous spontaneous abortion and a normal pregnancy at the same period of pregnancy. In comparison with primigravid women, the odds ratio for a fetal loss in the current one was 1.41 [95% confidence interval (CI) = 0.81-2.43] among women with one previous pregnancy ending in induced abortion, 4.43 (95% CI = 1.46-13.36) among those with two previous induced abortions out of two pregnancies, and 1.35 (95% CI = 0.64-2.82) among women with three or more previous pregnancies ending in one or more induced abortions.

Abortion, Induced↗
PubMed1995

Pulmonary retention of ceramic fibers in silicon carbide (SiC) workers.

The fibrous inorganic content of post-mortem lung material obtained from 15 men who worked in the primary silicon carbide (SiC) industry was evaluated. Five men had neither lung fibrosis nor lung cancer (NFNC), six had lung fibrosis (LF), and four had lung fibrosis and lung cancer (LFLC). The workers had 23 to 32 years of exposure. Mean duration of exposure was 23.4 (SD 6.9) years in the NFNC group, 28.8 (SD 5.5) in the LF, and 32.3 (SD 9.0) in the LFLC group. Concentrations of SiC ceramic fibers and other fibrous minerals and angular particles were determined by transmission electron microscopy and energy dispersive spectroscopy. The geometric mean and geometric standard deviation lung concentrations of SiC ceramic fibers < 5 microns were not statistically different for the three groups (Mann-Whitney, p > 0.1). Pulmonary retention of SiC fibers > or = 5 microns showed an excess in LF and LFLC cases combined versus NFNC that approached statistical significance (Mann-Whitney, p = 0.06). There was a somewhat greater difference for lung retention of ferruginous bodies between NFNC and either LF or LFLC cases (Mann-Whitney, p = 0.02). SiC fibers > or = 5 microns and angular particles containing Si and especially ferruginous bodies were found at higher concentrations in LF and LFLC than in NFNC cases.

Air Pollutants, Occupational↗
PubMed1995

Young maternal age: a risk factor for childhood asthma?

Some studies indicate that children born to younger mothers are at higher risk for wheezing or asthma. I conducted a case-control study that included 457 new cases of asthma in 3- and 4-year-old children and an equal number of controls. I found that, in comparison with children of mothers 30 years of age or older, children of mothers age 26-30 years had an adjusted odd ratio (OR) of 1.16 [95% confidence interval (CI) = 0.73-1.85] of developing asthma; children of mothers between 21 and 25 years of age had an OR of 1.25 (95% CI = 0.76-2.07), and those whose mothers were 20 years of age or younger had an OR of 3.48 (95% CI = 1.08-11.22).

Adult↗
PubMed1994

Cohort study of silicon carbide production workers.

Silicon carbide is produced by a chemical reaction at high temperature between free crystalline silica and petroleum coke. The process generates airborne fibers and fibrogenic dusts such as alpha-quartz and cristobalite, which are also potentially carcinogenic. The authors report that this is the first cohort study in this industry. The study was carried out among 585 Québec silicon carbide production workers who had worked at any time from 1950 to 1980. Follow-up was to December 31, 1989, and 167 deaths were observed. The standardized mortality ratio (SMR) for all causes of death was 1.05 (95% confidence interval (CI) 0.90-1.23); for nonmalignant respiratory diseases it was 2.03 (95% CI 1.21-3.22); and for lung cancer it was 1.69 (95% CI 1.09-2.52). Controlling for smoking status using a Cox regression analysis, the risk for nonmalignant respiratory diseases and for lung cancer increased with exposure to total dust; in the highest exposure category, rate ratios (RR) were 4.08 (95% CI 1.11-14.96) for nonmalignant respiratory diseases and 1.67 (95% CI 0.57-4.83) for lung cancer. Results were in the expected direction, but the power of the study was low, because of small sample size and use of cumulative total dust as the exposure variable, which may be a poor indicator of lung irritants and other potential carcinogens in this industry, notably silicon carbide ceramic fibers.

Adult↗
PubMed1994

Health of family members caring for elderly persons with dementia. A longitudinal study.

OBJECTIVE: To estimate the change in depression and physical symptoms during a 1-year period in a group of caregivers for elderly persons with dementia and in a group of comparison participants. DESIGN: Cohort study with a comparison group. SETTING: Outpatient geriatric assessment unit and ophthalmology service in an acute care hospital. PARTICIPANTS: 218 close family members of a consecutive sample of patients with dementia and patients having cataract surgery were interviewed to obtain a baseline assessment. Of these, 86 caregivers (family members of patients with dementia) and 95 comparison participants (family members of patients with cataracts) were interviewed again approximately 1 year later. MAIN OUTCOME MEASURES: Center for Epidemiologic Studies depression scale and Aday and Andersen's 24-item physical symptom checklist. RESULTS: For the Center for Epidemiologic Studies depression score, the difference between caregivers and comparison participants with respect to change during the 1-year study period was 2.1 (95% CI, 1.0 to 5.2); for physical symptoms, the difference was 0.4 (CI, -0.3 to 1.1). A higher level of behavioral disturbance in the patients with dementia at time 1 and institutionalization of the patient between time 1 and time 2 were predictive of worsening caregiver depression and physical symptoms during the study period. The magnitude and direction of changes in caregiver health varied considerably. CONCLUSIONS: Overall mean changes in depression and physical symptoms during 1 year were small. The observed variability in the individual response to the caregiving situation suggests that future research should focus on the identification of salient prognostic factors.

Aged↗
PubMed1994

A long-term follow-up study of asymptomatic hepatitis B surface antigen-positive carriers in Montreal.

BACKGROUND/AIMS: Prospective studies from the Far East and Alaska have shown an increased mortality from cirrhosis and/or hepatocellular carcinoma in asymptomatic hepatitis B virus (HBV) carriers. The magnitude of this risk in apparently healthy North American carriers remains undefined. METHODS: The outcomes of 317 asymptomatic hepatitis B surface antigen-positive carriers from the Montreal area were examined after 16 years of follow-up. A majority of carriers were of French Canadian origin, were positive for antibody to hepatitis B e antigen, and had normal serum transaminase levels; institutionalization in orphanages as infants or children was the most important epidemiological risk factor, suggesting horizontal transmission of HBV during childhood. RESULTS: At follow-up, mean age was 46 +/- 8 years; 3 carriers had died of HBV-related cirrhosis, 1 of alcoholic cirrhosis, and 9 of causes unrelated to liver disease. No carrier died of hepatocellular carcinoma; had the risk of hepatocellular carcinoma been similar to that reported from the Far East and Alaska, 17 cases of hepatocellular carcinoma-related deaths would have been expected. During follow-up, the annual negativation rate for hepatitis B surface antigen was 0.7%. CONCLUSIONS: In asymptomatic HBV carriers from Montreal, a majority are "healthy" carriers and remain asymptomatic after 16 years of follow-up and the risk of death from HBV-related cirrhosis and/or hepatocellular carcinoma is low.

Adult↗
PubMed1993

Childhood asthma and indoor environmental risk factors.

In a case-control study carried out in Montréal, Québec, Canada, between 1988 and 1990, indoor environmental factors were studied in relation to the incidence of asthma among 3- and 4-year-old children. Cases (n = 457), whose parents were recruited at a hospital emergency room, were children who had a first-time diagnosis of asthma (International Classification of Diseases, Ninth Revision, code 493) made by a pediatrician. Controls (n = 457) were chosen from family allowance files and were matched with case children on age and census tract. A telephone interview was administered to the children's parents. A 20% feasibility subsample was chosen to wear a nitrogen dioxide monitoring badge during a 24-hour period. Multiple conditional logistic regression analysis showed that after personal susceptibility factors were controlled for, the following were independent risk factors for asthma: the mother's heavy smoking (odds ratio (OR) = 2.77, 95% confidence interval (CI) 1.35-5.66), use of a humidifier in the child's room (OR = 1.89, 95% CI 1.30-2.74), and the presence of an electric heating system in the home (OR = 2.27, 95% CI 1.42-3.65). The presence of other smokers in the home was not quite significant (OR = 1.82, 95% CI 0.98-3.38). A history of pneumonia, the absence of breast feeding, and a family history of asthma were also significant risk factors. In a separate unmatched multivariate analysis of subjects who had worn the nitrogen dioxide badge, there was a dose-response relation between nitrogen dioxide (in parts per billion) and asthma. These results confirm the role of susceptibility factors in asthma and show that indoor environmental factors contribute to the incidence of asthma.

Air Pollutants↗
PubMed1993

Pregnancy loss and work schedule during pregnancy.

Shift work has been associated with many health complaints, but its relation with pregnancy loss has rarely been studied. We compared the work schedule during pregnancy of 331 women with a pregnancy loss with that of 993 pregnant women matched on gestational age. The risk of pregnancy loss was four times higher among women with fixed evening work schedules in comparison with women on a fixed day schedule (odds ratio = 4.17; 95% confidence interval = 2.19-7.92), and more than twice as high among those on a fixed night schedule (odds ratio = 2.68; 95% confidence interval = 0.53-13.43).

Cross-Sectional Studies↗
PubMed1993

Circadian time-dependent response of childhood lymphoblastic leukemia to chemotherapy: a long-term follow-up study of survival.

The evolution of 118 children treated for acute lymphoblastic leukemia between 1976 and 1984, and followed until 1991, was reviewed. Maintenance chemotherapy consisted of daily 6-mercaptopurine (6-MP), weekly methotrexate (MTX), and monthly vincristine and prednisone. Eighty-two children took 6-MP and MTX in the morning, and 36 took them in the evening. Disease-free survival, as determined by Kaplan-Meier analysis, was better for children on evening chemotherapy. Regression analysis (Cox proportional hazards model, with evening versus morning schedule as exposure variable, and age at diagnosis, leucocytosis at diagnosis, and sex as covariates) showed that for those surviving free of disease for longer than 78 weeks, the risk of relapse was 2.56 times greater for the morning schedule than for the evening one.

Antineoplastic Combined Chemotherapy Protocols↗