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PubMed2000

Bone mineral metabolism in adults with beta-thalassaemia major and intermedia.

Bone disease is an important cause of morbidity in older patients with beta-thalassaemia major and intermedia. We studied 27 women and 23 men with beta-thalassaemia major (37) and intermedia (13) whose mean age was 32.3 +/- 9.7 years. Bone mineral density (BMD) of the lumbar spine, femoral neck and distal radius was determined by dual-energy X-ray absorbiometry (DXA). The longitudinal change in BMD over a mean of 5.6 years was determined in 19 patients. Serum 25-hydroxyvitamin D, insulin growth factor-1 (IGF-1), bone formation markers bone-alkaline phosphatase, osteocalcin and the resorption marker urinary N-telopeptide cross-linked type 1 collagen (NTx) were determined. The BsmI vitamin D receptor (VDR) gene polymorphism was analysed. Reduced BMD (Z-score < -2) was present in 89%, 62% and 73% of patients in the spine, hip and radius respectively. Vitamin D deficiency was found in 62%, decreased IGF-1 in 72% and increased urinary NTx in 84% of patients. Serum IGF-1 correlated with spine and hip BMD (r = 0.4, r = 0.39, P < 0.01 respectively), and NTx correlated with the hip BMD Z-score (r = 0.35 P < 0.05). The mean annual percentage change in spine BMD was -1.36%. Patients with the VDR BB genotype had lower spine BMD than patients with the bb genotype. In conclusion, bone loss continues in adult thalassaemia patients and is associated with increased bone resorption and decreased IGF-1. The BsmI VDR gene polymorphism is associated with osteopenia in thalassaemia.

25-Hydroxyvitamin D 2↗
PubMed1982

Early maxillary orthopaedics as a supplement to conventional primary surgery in complete cleft lip and palate cases - long-term results.

29 patients with complete uni- or bilateral cleft lip and palate were followed up the age of 15 to 20 years after having undergone early maxillary orthopaedics as a supplement to conventional primary surgery. Longitudinal changes in their facial pattern are demonstrated by means of Enlow's cephalometric analysis. The ultimate sagittal skeletal imbalance is more than 50% of the cases seems to be related to inadequate primary surgery (lip closure before 5 months of age, complete palatal closure before 2 years of age). Evidently, initial facial pattern and functional habits also play an important role. Functional disturbances due to scarring are discussed with a view to their influence on facial development.

Adolescent↗
PubMed2000

Relationship between E-selectin L/F554 polymorphism and blood pressure in the Stanislas cohort.

We investigated the relationship between polymorphisms of the E-selectin gene SELE (L/F554, S/R128 and 98G/T), a cell adhesion molecule, and interindividual variability in blood pressure and changes over time. The study population was extracted from the Stanislas cohort (1006 families), a cohort of nuclear families volunteering for a free health check-up and recruited by the Center of Preventive Medicine in Nancy (CMP) between 1993 and 1994. For this specific study 359 men and 337 women were selected from families who had already visited the CMP 11 years before recruitment of the Stanislas Cohort. Measurements of blood pressure 11 years before (t(-11)) and at the time of recruitment (t(0)), and all other measurements necessary for the analysis (body mass index, lipids, SELE genotypes) were available. Pregnant women or subjects taking antihypertensive, lipid-lowering, or anti-inflammatory medications were excluded from the study. During the follow-up period systolic and diastolic blood pressures were lower in SELE F554 allele carriers than in those with the L/L554 genotype (P<0.05), but longitudinal changes were not related to any SELE polymorphism. Multiple regression analysis showed that at t(-11) SELE L/F554 polymorphism was associated with both systolic and diastolic blood pressure levels (P<0.01 and P<0.05, respectively). However, these associations were no longer present at t(0). Our results suggest an age-specific effect of the SELE L/F554 polymorphism on blood pressure levels. If confirmed in other studies, these findings would suggest that assessment of common variation in an adhesion molecule could be useful in predicting blood pressure.

Adult↗
PubMed2003

Characterisation of the guinea pig model of osteoarthritis by in vivo three-dimensional magnetic resonance imaging.

OBJECTIVE: To characterise longitudinal changes in joint integrity and cartilage volume in vivo in the guinea pig spontaneous osteoarthritis (OA) model by magnetic resonance imaging (MRI). METHODS: Guinea pigs knee were imaged in vivo by high-resolution three-dimensional (3D) MRI between the ages of 3 and 12 months. Image analysis was performed to assess qualitative knee joint changes between 3 and 12 months (n=16) and quantitative volumetric changes of the medial tibial cartilage between 9 and 12 months (n=7). After imaging, animals were killed and knees were assessed macroscopically and histologically. RESULTS: From 3 to 6 months qualitative observation by MRI and histopathology indicated localised cartilage swelling on the medial tibial plateau. At 6 months, bone cysts had developed in the epiphysis. At 9 months, we observed by MRI and histopathology, fragmentation of the medial tibial cartilage in areas not protected by the meniscus. Cartilage degeneration had intensified at 12 months with evidence of widespread loss of cartilage throughout the tibial plateau. Segmentation of the MR cartilage images showed a 36% loss of volume between 9 and 12 months. CONCLUSIONS: We have achieved 3D image acquisition and segmentation of knee cartilage in a guinea pig model of chronic OA, which permits measurements previously only possible in man. High resolution and short acquisition time allowed qualitative longitudinal characterisation of the entire knee joint and enabled us to quantify for the first time longitudinal tibial cartilage volume loss associated with disease progression.

Animals↗
PubMed1997

Linear growth retardation in Zanzibari school children.

This paper describes the longitudinal changes in height and weight of children in school grades 1-3 on Pemba Island, Zanzibar, a poor rural population in which parasitic infections and anemia are highly prevalent. Heights and weights of children were measured at base line, and 6 and 12 mo later, and were compared with U.S. reference data. At base line, the prevalence of height-for-age Z-score < -2 rose from 14% in 7-y-old children to 83% in 13-y-old children. Prevalence of weight-for-age Z-score < -2 in children < 10 y was approximately 10% or less. Median 6-mo height increments for Pembian boys were around the 5th percentile at age 8 and around the 10th percentile from age 9 to 13 y. Height increments for girls improved from below the 25th percentile to above the median in this age range. Based on the longitudinal yearly gains observed, boys accumulate a height deficit of 11.9 cm and girls 8.5 cm, relative to the reference population. In multivariate analyses, a small part of the variability in growth increments was explained by ascariasis and anemia (for weight gain) and schistosomiasis (for height gain). A review of other growth data from rural African Bantu populations provides supporting evidence that stunting occurs in older as well as younger children. It has been controversial whether school-based health and nutrition interventions could induce catch-up growth in already stunted children. Our results suggest that appropriate interventions might actually prevent stunting in late childhood.

Adolescent↗
PubMed2002

Longitudinal follow-up study of smoker's lung with thin-section CT in correlation with pulmonary function tests.

PURPOSE: To evaluate thin-section computed tomography (CT) in depicting longitudinal changes in the lung parenchyma. MATERIALS AND METHODS: One hundred eleven volunteers underwent sequential examination with thin-section CT and pulmonary function tests over a mean period of 5.5 years. According to their smoking habits between initial evaluation (T0) and follow-up (T1), the subjects were classified as persistent current smokers (n = 57), persistent nonsmokers (n = 31), persistent ex-smokers (n = 13), or quitters (n = 10). RESULTS: Significant differences in CT findings between T0 and T1 were seen in only the group of persistent current smokers, who showed a higher frequency of emphysema (40% vs 26%; P =.005) and ground-glass attenuation (42% vs 28%; P =.02). Individual analysis of follow-up CT scans in the 19 persistent current smokers with micronodules at T0 demonstrated (a) no changes in seven cases, (b) a higher profusion of micronodules in seven cases, and (c) replacement of micronodules with emphysema in five cases. Subjects with emphysema and/or areas of ground-glass attenuation at T0 had a significantly more rapid decline in lung function than did those with a normal CT scan. CONCLUSION: Emphysema and/or ground-glass attenuation are linked with impairment of ventilatory lung function over time in persistent current smokers.

Adult↗
PubMed2001

[Association between E-selectin Leu554Phe polymorphism and blood pressure in the Stanislas cohort].

We investigated the relationship between polymorphisms of the E-selectin gene, SELE (L/F554, S/R128 and 98G/T), a cell adhesion molecule, and interindividual variability in blood pressure and changes over time. The study population was extracted from the Stanislas Cohort (1006 families), a cohort of nuclear families volunteering for a free health check-up and recruited by the Centre of Preventive Medicine in Nancy (CMP) between 1993 and 1994. For this specific study, 359 men and 337 women were selected from families that had already visited the CMP 11 years before the recruitment of the Stanislas Cohort. Measurements of blood pressure at the time -11 years (t-11) and at the time of recruitment (t0), and all other measurements necessary for the analysis (BMI, lipids, SELE genotypes) were available. Pregnant women or subjects taking antihypertensive, lipid lowering or anti-inflammatory medications were excluded from the study. During the follow-up period, systolic and diastolic blood pressure (SBP and DBP) were lower in SELE F554 allele carriers than in those with the L/L554 genotype (p < or = 0.05), whereas longitudinal changes were not related to any SELE polymorphism. Multiple regression analysis showed that at t-11 SELE L/F554 polymorphism was associated with both SBP and DBP levels (p < or = 0.01 and p < or = 0.05, respectively). However, these associations were no longer present at t0. Our results suggest an age-specific effect of the SELE L/F554 polymorphism on blood pressure levels. If confirmed in other studies, these findings would suggest that assessment of common variation in an adhesion molecule could be useful in predicting blood pressure.

Adult↗
PubMed1998

The feed-back regulation of erythropoietin production in healthy humans.

The proposed oxygen-dependent feed-back loop regulation of EPO production (Fogh 1978, Erslev 1991, LeHir et al 1991, Nielsen 1991) is mainly supported by data from studies in animals and cell cultures. The feed-back loop and its dependence on oxygen was therefore challenged by studies in healthy humans: Exposure of humans to different levels of acute and continued altitude hypobaria provided evidence for an oxygen dependency of the EPO response. This response is consistent with the proposed feed-back loop regulation of EPO production. Exposure to continued altitude hypobaria demonstrated that the decline in human EPO production is initiated before an EPO-induced erythropoiesis is detectable, and that this decline is related to a concomitant decrease in the haemoglobin-oxygen affinity. Contrary to the feed-back loop, this time-relation indicate that the feed-back regulation of EPO production during continued hypobaric hypoxia is exerted primarily through a decrease in the haemoglobin-oxygen affinity, rather than by the effects of an EPO-stimulated erythropoiesis. A laboratory experiment demonstrated that the lowering of PaO2 by short-term breathing of hypoxic gas could trigger human EPO production. Since the possible influence of spontaneous non-hypoxic variations in EPO production was taken into account, the magnitude of the human EPO response to hypoxia was found to be less than formerly observed in humans and rodents. Contrary to former observations in rodents, the triggering of human EPO production was not related to a hypoxic or normoxic increase of the haemoglobin-oxygen affinity, and normocapnia, without changes in pH or haemoglobin-oxygen affinity, sufficed to suppress the human EPO response to hypoxia. Together with the altitude studies, these results have demonstrated that human EPO production is dependent on, and triggered by, oxygen deprivation, and that changes in the haemoglobin-oxygen affinity play a role mainly in the feed-back regulation rather than in the triggering of human EPO production. Increased circulating levels of the proinflammatory cytokine IL-6 was found in healthy humans during four days of altitude exposure as compared with sea level. The other proinflammatory cytokines IL-1 beta, and TNF alpha remained unchanged, and the increased serum IL-6 did not induce production of c-reactive protein. However, a relation was shown between serum IL-6, SaO2, and serum EPO. These observations in humans confirm earlier in vitro studies in that IL-6 may have a co-stimulatory role on EPO production in the presence of hypoxia. Comparable circadian variations in human EPO production were shown in sedentary subjects, athletes, and healthy but hypoxaemic subjects. Human EPO production could not be triggered by one hour of high-intensity exercise, whereas longitudinal changes in exercise showed a trend of relation between human EPO production, serum concentration of free testosterone, and indices of body composition. These results have demonstrated an endogenous, probably hormonal, and oxygen-independent regulation of human EPO production, which is at variance with the oxygen dependent feed-back loop regulation of EPO production. Conclusively, the present investigations have shown that the feed-back loop regulation of EPO production, as described by studies in rodents and cell-culture models, cannot be applied to the physiology of human EPO production without modifications.

Animals↗
PubMed2007

Associated and predictive factors of sleep disturbance in advanced cancer patients.

Little attention has been paid to sleep disturbance experienced by advanced cancer patients. The purpose of the present study was to investigate longitudinal change in sleep disturbance and to identify factors that associated with and predicted sleep disturbance among 209 consecutive terminally ill cancer patients. Patients were assessed twice for sleep disturbance by one item of the structured clinical interview for assessing depression, once at the time of their registration with a palliative care unit (PCU) (baseline) and again at the time of their PCU admission (follow-up), and possible associated medical and psychosocial factors were evaluated. The proportions of patients with obvious sleep disturbance at baseline and follow-up were 15.3 and 25.9%, respectively. Sixty-seven percent of the subjects showed some sleep status changes, including both aggravation and improvement, between baseline and follow-up. Being younger, having diarrhea and living alone were significantly associated with sleep disturbance at baseline, and the increase of psychological distress was the only significant predictive factor for sleep disturbance at follow-up. These findings suggest that psychological distress is a possible key cause of sleep disturbance and management of psychological distress may be one promising strategy for prevention of sleep disturbance among advanced cancer patients.

Female↗
PubMed1993

Serum antibodies to viral pathogens and Toxoplasma gondii in HIV-infected individuals.

Sera from 38 HIV-infected individuals were examined longitudinally for antibodies to viruses that may increase morbidity in HIV infection, as well as commensal viruses and Toxoplasma gondii. HTLV infection was seen in Norway for the first time as four patients had antibodies to HTLV-II and one had antibodies to HTLV-I. Antibodies to hepatitis B virus (HBV) were found in 47.2%, while 21.6% of the patients had antibodies to hepatitis C virus (HCV). There was no evidence of acquisition of HBV or HVC during the mean observation period of 2 years. A titre increase in CMV antibody with time was observed for 7 out of 21 patients and a decrease for 2 patients. For Epstein-Barr virus, herpes simplex, varicella-zoster, rubella and measles viruses, human polyomavirus BK as well as for Toxoplasma gondii, antibody prevalences and titres were within the range seen in normal populations. Also, no longitudinal changes were observed in titres of these antibodies, indicating that humoral immunity remained intact during the study period. The high prevalences of HTLV-I/II, HBV and HCV antibodies in HIV-infected patients reflect common modes of virus transmission, and the fluctuations in CMV antibody titre are indicative of reactivations. Such coinfections may influence disease progression.

Adult↗
PubMed2000

Progress toward attainment of the Healthy People 2000 objectives in the U.S. Army: measured by health risk appraisal results.

BACKGROUND: Healthy People 2000 (HP2000) is a national agenda of health promotion and disease prevention objectives, with specific health behavior goals in 22 priority areas. The U.S. Army Health Risk Appraisal (HRA) is a self-administered health-habits survey, inquiring about tobacco and alcohol use, physical activity, nutrition, and safety-related practices, given to more than 400,000 active-duty U.S. Army soldiers in the 1990s. This article compares the health behaviors of U.S. Army soldiers, as measured by the HRA, with the HP2000 objectives. METHODS: We compared cross-sectional analyses of self-reported health behaviors of active-duty Army personnel responding to HRA questionnaires in 1991 (n=78,256) and in 1997-1998 (n=59,771) with corresponding HP2000 objectives. We also calculated longitudinal changes for personnel who took more than one HRA (n=86,393). RESULTS: By 1997-1998, the Army exceeded HP2000 physical fitness goals by at least 50% and also exceeded goals for eating high-fiber foods and using bicycle helmets. The Army did not meet goals for nutrition, tobacco use, and seat-belt use. CONCLUSIONS: The Army has made good progress toward the HP2000 goals. However, improvement is needed to meet the tobacco, nutrition, and safety goals.

Adolescent↗
PubMed1995

Hostility and erosion of marital quality during early marriage.

We examined the association between hostility and longitudinal changes in marital quality in a sample of 53 newlywed couples who were in their first marriages and were without children. Spouses' reports of marital quality were assessed initially at an average of 5 months into marriage and, thereafter, at three follow-up points approximately 1, 2, and 3 years subsequent to the date of marriage. Individual growth models were computed to assess the rate of change of marital quality. Hostility among husbands was significantly associated with linear decreases in their own, and their wives', reports of marital quality, even after controlling for the passage of time and the correlated variable of neuroticism. Results are consistent with the psychosocial vulnerability model of hostility and illness (Smith, Health Psychol. 11: 139-150, 1992), which posits that associations between hostility and heightened risk for morbidity and mortality are partially mediated by poor-quality relationships that develop as a consequence of the abrasive interpersonal properties of hostility.

Adult↗
PubMedDate not supplied

The effect of hormone replacement therapy on appendicular lean tissue mass in early postmenopausal women.

OBJECTIVE: The impact of hormone replacement therapy (HRT) on skeletal muscle mass is still a controversial issue in women's health. Some authors hypothesize anabolic effects, others catabolic. These hypotheses, however, await confirmation by longitudinal observations based on more direct measurements of muscle mass. The aim of the present preliminary study was to evaluate the effect of a 3-year HRT program on appendicular lean tissue mass (LTM(A)) in early postmenopausal women aged 45-54 years. DESIGN: This was a randomized, double-blind and placebo-controlled trial. Women received HRT with 2 mg estradiol valerate combined either continuously with 1 mg cyproterone acetate (days 1-28; n = 15) or sequentially with 75 mug levonorgestrel (days 17-28; n = 15), or placebo (n = 18). Serum estradiol was measured by radioimmunoassay. LTM(A) was measured by dual photon absorptiometry (baseline) and dual energy X-ray absorptiometry (years 2 and 3). RESULTS: Baseline serum estradiol did not show significant correlation with the respective LTM(A) (r = 0.018, p = 0.88, n = 75). Cross-sectional analysis found no significant differences between the intervention groups at any time points. The longitudinal changes between years 2 and 3 showed a trend toward decreasing LTM(A) in those receiving HRT (-0.08 +/- 0.12 kg, n = 30) compared to those receiving placebo (0.12 +/- 0.25 kg, n = 18, p = 0.44). CONCLUSIONS: The present preliminary study did not find significant effects on LTM(A) caused by HRT. The trends toward decreasing LTM(A) in the HRT groups might suggest catabolic rather than anabolic effects. These trends, however, await confirmation by larger clinical trials.

Absorptiometry, Photon↗
PubMed1999

A novel, short, and simple questionnaire to measure health-related quality of life in patients with chronic obstructive pulmonary disease.

A novel, short, and simple questionnaire, the Airways Questionnaire 20 (AQ20), has been developed to measure and quantify disturbances in the health-related quality of life (HRQoL) of patients with asthma or chronic obstructive pulmonary disease (COPD). The AQ20 has 20 items with yes/no responses, and should take 2 min to complete and score. The purpose of this study was to assess the discriminative properties and responsiveness of the AQ20 in patients with COPD. First, in a cross- sectional study, 165 patients with mild-to-severe COPD (mean age, 69 +/- 7 yr; FEV1, 40 +/- 16% of predicted) completed the AQ20, the St. George's Respiratory Questionnaire (SGRQ), the Chronic Respiratory Disease Questionnaire (CRQ), pulmonary function tests, a progressive cycle ergometer exercise test, and an assessment of their dyspnea and anxiety. The score distribution of the AQ20 was skewed toward the mild end of the scale, whereas the SGRQ and CRQ showed a normal distribution. The AQ20 showed a moderately strong correlation with the maximal oxygen uptake and the assessment of dyspnea (Spearman's correlation coefficients [rs] = -0.49, -0.60, respectively), but a weak correlation with the FEV1 (rs = -0.18). Moderate to strong correlations were also recognized between the AQ20 and SGRQ and CRQ (rs = -0.80, -0.72, respectively). Multiple regression analysis revealed that dyspnea and anxiety accounted for 43% of the variance in the AQ20, almost the same as in the SGRQ and CRQ. Second, longitudinal changes over time in the FEV1, AQ20, SGRQ, and CRQ were examined in 86 patients with newly detected COPD (mean age, 69 +/- 8 yr; FEV1, 45 +/- 19% of predicted). All three measures showed significant improvements in their scores over a 3-mo period after initiating medical intervention. The change in the AQ20 showed a moderate to strong correlation with each dimension of the SGRQ and CRQ (rs = 0.56, -0.52, respectively), but no significant correlation was noted with the FEV1. In conclusion, the AQ20 may have discriminative properties and responsiveness that are similar to more complex questionnaires such as the SGRQ and CRQ. Because it is short and can be quickly answered and scored, the AQ20 may be useful in studies with limited time for HRQoL assessments.

Aged↗
PubMed1999

Peritoneal transport properties and dialysis dose affect growth and nutritional status in children on chronic peritoneal dialysis. Mid-European Pediatric Peritoneal Dialysis Study Group.

To evaluate a possible effect of peritoneal transport properties and dialysis dose on the physical development of children on chronic peritoneal dialysis, a cohort of 51 children was prospectively followed for 18 mo. Peritoneal transport characteristics were assessed by serial peritoneal equilibration tests (PET), dialysis efficacy by dialysate and residual renal clearance measurements, and growth and nutritional status by the longitudinal changes (delta) of height SD score (SDS), body mass index (BMI) SDS, and serum albumin. delta height SDS was negatively correlated with the creatinine equilibration rate observed in the initial PET (r = -0.31, P < 0.05). Multiple regression analysis confirmed the negative effect of the high transporter state (partial r2 = 0.07), and disclosed an additional positive effect of dialytic C(Cr) (partial r2 = 0.11) and a weak negative effect of daily dialysate volume (partial r2 = 0.04) on delta height SDS. delta BMI SDS was strongly age-dependent (r = -0.48, P < 0.001); while relative body mass gradually increased below 4 yr of age, it remained stable in older children. Positive changes in BMI SDS were associated with rapid PET creatinine equilibration rates (univariate r = 0.35, P < 0.05) and/or large dialysate volumes (multivariate partial r2 = 0.11), suggesting a role of dialytic glucose uptake in the development of obesity. The change in serum albumin concentrations was positively correlated with dialysate volume (partial r2 = 0.14), and negatively affected by dialytic protein losses (partial r2 = 0.06). In conclusion, the peritoneal transporter state is a weak but significant determinant of growth and body mass gain in children on chronic peritoneal dialysis. Rapid small solute equilibration contributes to impaired growth but enhanced acquisition of body mass. Dialytic small solute clearance has a weak positive effect on statural growth independent of the transporter state, but does not affect body mass gain.

Adolescent↗
PubMed2006

A model for quantitative changes in the magnetic resonance parameters of muscle in children after therapeutic irradiation.

PURPOSE/OBJECTIVE: This study aimed to develop objective models of radiation effects on musculature in children with soft tissue sarcoma using treatment dosimetry and clinical and quantitative magnetic resonance imaging (MRI) parameters that may be used to guide treatment planning or predict side effects. METHODS: In the initial 13 patients undergoing external beam radiation therapy (RT) on a Phase II study of conformal or intensity-modulated RT for the treatment of soft tissue sarcoma approved by an Institutional Review Board, we evaluated quantitative MRI changes in the musculature to assess radiation-related treatment effects. Patients with soft tissue sarcoma, including Ewing's sarcoma, had quantitative T1, T2 and dynamic enhanced MRI (DEMRI) performed before, during (Week 4) and after RT (Week 12). Regions of interest were selected in consistent locations within and outside the high-dose regions (on ipsilateral and contralateral sides when available). Mean RT dose, T1, T2 and DEMRI parameters were calculated and modeled using a mixed random coefficient dose model. RESULTS: The mean doses to the high- and low-dose regions were 56.4 Gy (41.8-75.3 Gy) and 13.0 Gy (0.1-37.5 Gy), respectively. Compared with tissues distant from the tumor bed, maximal enhancement was significantly increased in tissues adjacent to the tumor/tumor bed prior to RT (60.6 vs. 44.2, P=.045) and remained elevated after 12 weeks. T1 was significantly elevated in tissues adjacent to the tumor bed prior to RT (942.4 vs. 759.0, P=.0078). The slope of longitudinal change in T1 was greater for tissues that received low-dose irradiation than those that received high-dose irradiation (P=.0488). The effect of dose on the slope of T2 was different (P=.0333) when younger and older patients are compared. CONCLUSIONS: Acute affects of irradiation in muscle are quantifiable via MRI. These models provide evidence that quantifiable MRI parameters may be correlated with patient parameters of radiation dose and clinical factors including patient age. Long-term follow-up will be required to determine if acute changes correlate with clinically significant late effects.

Child↗
PubMed1991

Grain dust and lung function. Dose-response relationships.

Grain dust exposure has been associated with both acute and chronic respiratory abnormalities. We sought to answer two questions with regard to this exposure: (1) is there a dose-response relationship between grain dust and respiratory abnormalities, and (2) is there evidence to suggest that the allowable exposure (currently 10 mg/m3 in Canada) be lowered? We compared respiratory symptoms and lung function among 454 grain elevator workers and 55 civic workers to estimates of lifetime average grain dust exposure. A total of 781 personal air samples representing 20 different job titles over a 15-yr period were used to construct a job title-time period matrix for average dust exposure levels. The matrix was applied to each worker's detailed job history to obtain a value for estimated cumulative and average dust exposure. Significant dose-response relationships were seen for chronic phlegm production, breathlessness on exertion, FEV1, and FVC; and dose-response trends were evident for the longitudinal change in both FEV1 and FVC. Workers with estimated average exposure between 4 and 9 mg/m3 were found to have significantly lower values for FEV1 and FVC compared to both grain workers exposed to less than 4 mg/m3 on average and civic workers, despite no difference in duration of employment among these groups. The results indicate a strong dose-response relationship between grain dust exposure and both respiratory symptoms and lung function and also suggest that the current Canadian allowable exposure level of 10 mg/m3 is too high.

British Columbia↗
PubMedDate not supplied

Predicting elderly outpatients' life-sustaining treatment preferences over time: the majority rules.

BACKGROUND: This study describes longitudinal changes in the composition and accuracy of modal life-sustaining treatment preferences as predictors of patients' treatment preferences. METHOD: Healthy outpatients age 65 and older and their surrogate decision makers recorded preferences for 4 treatments in 9 hypothetical illness scenarios 3 times over a period of 2 years. A statistical prediction model, based on patients' modal preferences, was created using initial responses and updated 2 years later. RESULTS: When reestimating the model at 2 years, 4 of 27 items in the model created using baseline responses no longer reached the threshold for inclusion, but 5 new items did meet criteria. All modal preference changes reflected a trend toward refusing treatment. Both the original and updated models were more accurate in predicting patients' preferences than were surrogates making concurrent predictions. Adding covariates (e.g., gender, age, presence of plans for future medical care) did not alter the model's predictive superiority over surrogates. CONCLUSIONS: Models using modal preferences are useful to patients, surrogates, and physicians when trying to accurately discern end-of-life treatment choices, but the models must be updated periodically.

Actuarial Analysis↗