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D C Christiani

Publications and source records attributed to D C Christiani.

At least 19 recordsLinked to original sources
PubMed2006

Interleukin-10 polymorphism in position -1082 and acute respiratory distress syndrome.

The GG genotype of the interleukin (IL)-10 promoter polymorphism in position -1082 (-1082GG) has been associated with increased IL-10 production. The current authors hypothesised that the -1082GG genotype is associated with the development of, and outcomes in, acute respiratory distress syndrome (ARDS). A nested case-control study was conducted in 211 Caucasian cases of ARDS and 429 controls who were admitted to an intensive care unit with sepsis, trauma, aspiration or massive transfusions. Cases were followed for organ failure and 60-day mortality. The -1082GG genotype was associated with the development of ARDS, but only in the presence of a significant interaction between the -1082GG genotype and age. Among patients with ARDS, the -1082GG genotype was associated with decreased severity of illness on admission, lower daily organ dysfunction scores and lower 60-day mortality. In conclusion, the high interleukin-10-producing -1082GG genotype may be associated with variable odds for acute respiratory distress syndrome development depending on age. Among those with acute respiratory distress syndrome, the -1082GG genotype is associated with lower mortality and organ failure. Further studies are needed to confirm these findings.

Adolescent↗
PubMed2005

Exposure to welding fumes is associated with acute systemic inflammatory responses.

AIMS: To investigate the acute systemic inflammatory response to welding fume exposure. METHODS: Twenty four welders (42% smokers) and 13 non-exposed controls (23% smokers) were monitored at a welding school. Exposure to fine particulate matter (PM2.5) was assessed using cyclone samplers. Markers of systemic inflammation, including C-reactive protein (CRP), fibrinogen, and white blood cell (WBC) levels, were determined in peripheral blood samples collected at baseline and after 5.3 (SD 1.0) hours of exposure. RESULTS: The median PM2.5 concentration for welders was 1.66 mg/m3, which was significantly greater than that for controls (0.04 mg/m3). Compared to non-smokers, smokers had a significantly higher baseline WBC count, but comparable levels of CRP and fibrinogen. In non-smokers, welding fume exposure was associated with a significant increase in WBC and neutrophil counts immediately following exposure (+0.8x10(3)/mul, 95% CI 0.1 to 1.6, and +1.0x10(3)/mul, 95% CI 0.4 to 1.7, respectively). A significant decrease in fibrinogen levels was observed in non-smokers (-32 mg/dl, 95% CI -63 to -1). No significant changes in WBC, neutrophil, and fibrinogen levels were found in smokers. Sixteen hours after welding exposure, CRP levels were found to be significantly increased in both non-smokers and smokers (0.90 mg/l, 95% CI 0.17 to 1.64). PM2.5 concentrations were found to be significantly associated with absolute neutrophil counts in non-smokers, and CRP levels in both non-smokers and smokers. CONCLUSIONS: High levels of welding fume exposure induce acute systemic inflammation in a relatively young, healthy working population. These results also suggest that smoking may modify the effect of welding fume exposure on specific inflammatory markers.

Acute Disease↗
PubMed2005

Occupation and COPD.

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Air Pollutants, Occupational↗
PubMed2005

Long driving time is associated with haematological markers of increased cardiovascular risk in taxi drivers.

AIMS: To examine the association between driving time and changes in haematological markers of increased risks for cardiovascular diseases (CVD). METHODS: The authors conducted a cross sectional analysis of baseline data from the Taxi Drivers' Health Study cohort in Taipei, Taiwan. They retrieved information on comorbidity, laboratory tests, age, and anthropometric measures from medical records of 1157 subjects (mean age 44.6 (SD 8.6) years). Whole blood cell (WBC) count was used as the primary haematological marker for increased CVD risk, and platelet count and haematocrit as the secondary markers. Standardised questionnaires were implemented to collect information on demographics, lifestyle, work related physical and psychosocial factors, and driving time profiles. Multiple regression was used to estimate the adjusted effects of driving time on three haematological markers. RESULTS: The mean measured hematological marker was 6656 (SD 1656) cells x10(6)/l for WBC, 47.2 (SD 3.5) % for hematocrit, and 243 (SD 52) cells x10(9)/l for platelets. The driving time was 264 (SD 76) hours/month. Compared with drivers who drove < or =208 hours/month (1st quartile cut off), drivers who drove >208 hours/month had a higher WBC count (by 317 x10(6)/l; 95% CI 99 to 535), haematocrit (by 0.8%; 95% CI 0.3 to 1.2), and platelets (7.9 x10(9)/l; 95% CI 1.0 to 14.8). After adjusting for conventional CVD risk factors (age, sex, smoking, hypertension, diabetes, and hypercholesterolaemia), obesity, alcohol drinking, regular exercise, and sociodemographics (education, marital status, income, and so on), long driving time was still associated with significant increases in WBC and platelets, whereas the effect on haematocrit was diminished and became statistically non-significant. Additional controls for physical workload, self-perceived job stress, and job dissatisfaction did not alter the associations with increased WBC and platelets. CONCLUSIONS: Longitudinal studies are needed to confirm the observed cross sectional association and to further examine the specific occupational exposures accountable for the association between driving time and haematological markers of systemic inflammation and haemostatic alteration.

Adult↗
PubMed2005

-308GA and TNFB polymorphisms in acute respiratory distress syndrome.

The -308GA and TNFB1/2 polymorphisms of the tumour necrosis factor genes have been associated with increased susceptibility to, and mortality in sepsis, although, prior studies are not consistent. Their role in acute respiratory distress syndrome (ARDS) has not been evaluated. The current authors hypothesised that the -308A allele and TNFB22 genotype would be associated with increased susceptibility to, and mortality in ARDS. The above hypothesis was investigated in a nested case-control study of 441 Caucasian controls and 212 cases admitted to an intensive care unit with sepsis, trauma, aspiration or hyper-transfusions. The -308A and TNFB1 alleles were in linkage disequilibrium. These polymorphisms were not associated with ARDS susceptibility on crude analysis. On subgroup analyses, they were associated with either increased or decreased odds of developing ARDS depending on whether the clinical risk for ARDS results in direct or indirect pulmonary injury. The -308A allele was associated with increased 60-day mortality in ARDS, with the strongest association found among younger patients. There was no association between the TNFB polymorphism and ARDS mortality. The -308GA, but not the TNFB12, polymorphism was associated with increased mortality in acute respiratory distress syndrome, but their association with acute respiratory distress syndrome susceptibility depended on the site of injury predisposing to acute respiratory distress syndrome.

APACHE↗
PubMed2005

A 20-year follow-up study on chronic respiratory effects of exposure to cotton dust.

In order to evaluate chronic effects of long-term exposure to cotton dust on respiratory health, and the role of dust and endotoxin, longitudinal changes in lung function and respiratory symptoms were observed prospectively from 1981 to 2001 in 447 cotton textile workers, along with 472 silk textile controls. The results from five surveys conducted over the 20-yr period are reported, including standardised questionnaires, pre- and post-shift spirometric measurements, work-area inhalable dust sample collections and airborne Gram-bacterial endotoxin analysis. Cotton workers had more persistent respiratory symptoms and greater annual declines in forced expiratory volume in one second (FEV1) and forced vital capacity as compared with silk workers. After exposure cessation, in the final 5-yr period, the rate of FEV1 decline tended to slow in nonsmoking males, but not in nonsmoking females. Workers who reported byssinotic symptoms more persistently suffered greater declines in FEV1. Chronic loss in lung function was more strongly associated with exposure to endotoxin than to dust. In conclusion, the current study suggests that long-term exposure to cotton dust, in which airborne endotoxin appears to play an important role, results in substantial adverse chronic respiratory effects.

Byssinosis↗
PubMed2004

Occupational and personal factors associated with acquired lumbar spondylolisthesis of urban taxi drivers.

AIMS: To investigate the occupational and personal factors associated with lumbar spondylolisthesis in taxi drivers. METHODS: Cross-sectional analysis of the baseline data from the Taxi Drivers' Health Study cohort. Information was retrieved from the medical records of standardised lumbosacral spine plain films, age, and anthropometric measures of 1242 subjects. Acquired spondylolisthesis (ASL) was defined as non-lytic spondylolisthesis involving lumbar spines above L5. Questionnaires were used to gather information on demographic features, health behaviours, exercise, work related physical and psychosocial factors, and driving time profiles. Multiple logistic regression was used to model the odds ratio (OR) for prevalent ASL cases associated with personal and occupational factors. RESULTS: A total of 40 cases (3.2%) of ASL were diagnosed. Among those driving < or =5 years, 6-15 years, and >15 years, the estimated prevalence of lumbar spondylolisthesis was 1.1%, 2.4%, and 7.1% respectively. Results of multiple logistic regression suggested that taxicab driving >15 years (OR = 3.4, 95% CI 1.1 to 10.7, compared to driving < or =5 years), age (OR = 2.6, 95% CI 1.1 to 6.6 for age 46-55; and OR = 4.8, 95% CI 1.8 to 12.9 for age >55), body mass index > or =25 kg/m2 (OR = 2.2, 95% CI 1.1 to 4.6), and frequent strenuous exercise (OR = 2.2, 95% CI 1.1 to 4.5) were significantly associated with higher prevalence of spondylolisthesis. There was a consistent likely exposure-response relation between professional seniority and ASL prevalence. CONCLUSIONS: Longitudinal studies are needed to confirm the observed association between professional driving and spondylolisthesis, and to examine further the specific occupational exposures accountable for this association.

Adult↗
PubMed2003

Predictors of whole-body vibration levels among urban taxi drivers.

To identify a set of important WBV predictors that could be used to develop a statistical instrument for exposure assessment in a large epidemiologic study, a total of 432 WBV measures were taken from a sample of 247 male drivers in Taipei City, Taiwan. In accordance with the ISO 2631-1 (1997) methods, we measured the frequency-weighted vertical acceleration (z-axis) over drivers' seat surface, under conditions representing different types of rides (vacant vs. short vs. long) assigned to random destinations. Mixed effect models were used to analyse the WBV data including repeated measures. For this group of urban taxi drivers regularly exposed to WBV of low intensity (mean = 0.31 ms( - 2), ranging from 0.17 to 0.55 ms( - 2) r.m.s.), our analyses indicated that average driving speed was the primary predictor (p < 0.0001). As average driving speed increased, measured vertical acceleration increased in a quadratic-linear manner (p < 0.0001). Other WBV predictors, after adjusting for the effects of other covariates, included automobile manufacturer (p = 0.02), engine size (p = 0.04), body weight (p = 0.002), age (p = 0.02), use of seat cushion (p = 0.03), and traffic period (p = 0.02). Our study suggests that a similar statistical approach could be employed in future studies to improve the quality and efficiency of WBV exposure assessment in professional drivers.

Acceleration↗
PubMed2003

Gamma-glutamyltransferase and diabetes--a 4 year follow-up study.

AIMS/HYPOTHESIS: Gamma-glutamyltransferase (GGT) is located on the external surface of most cells and mediates the uptake of gluthathione, an important component of intracellular antioxidant defenses. An increase in GGT concentration has been regarded as a marker of alcohol consumption or liver disease. However, more subtle gradations in GGT could be informative because its expression is enhanced by oxidative stress and it could be released by several conditions inducing cellular stress. Recently, serum GGT concentrations have been associated with many cardiovascular disease risk factors or components of the insulin resistance syndrome. We did a prospective study with the hypothesis that serum GGT is a predictor of incident diabetes. METHODS: A total of 4,088 healthy men working in a steel manufacturing company were examined in 1994 and 1998. Diabetes was defined as a serum fasting glucose concentration of more than 126 mg/dl or the use of diabetes medication. RESULTS: There was a strong dose-response relation between serum GGT concentrations at baseline and the incidence of diabetes. In contrast to the 31% of men with GGT concentrations under 9 U/l, adjusted relative risks for incidence of diabetes for GGT concentrations 10-19, 20-29, 30-39, 40-49, and over 50 U/l were 8.0, 13.3, 12.6, 19.6 and 25.8, respectively. The associations of age and BMI with incident diabetes became stronger the higher the value of baseline serum GGT concentration. CONCLUSION/INTERPRETATION: This study suggests that an increase in GGT concentration within its physiological range is a sensitive and early biomarker for the development of diabetes.

Adult↗
PubMed2003

Respiratory symptoms and cotton dust exposure; results of a 15 year follow up observation.

AIMS: To determine chronic effects of long term exposure to cotton dust and endotoxin on incidence of respiratory symptoms and the effect of cessation of exposure. METHODS: Respiratory health in 429 Chinese cotton textile workers (study group) and 449 silk textile workers (control group) was followed prospectively from 1981 to 1996. Byssinosis, chest tightness, and non-specific respiratory symptoms were assessed by means of identical standardised questionnaires at four time points. Exposures to cotton dust and endotoxin were estimated using area samples collected at each survey. Incidence and persistence of symptoms were examined in relation to cumulative exposure and exposure cessation using generalised estimating equations (GEE). RESULTS: Among cotton workers, the cumulative incidence of byssinosis and chest tightness was 24% and 23%, respectively, and was significantly more common in smokers than in non-smokers. A high proportion of symptoms was found to be intermittent, rather than persistent. Among silk workers, no typical byssinosis was identified; the incidence of chest tightness was 10%. Chronic bronchitis, cough, and dyspnoea were more common and persistent in the cotton group than in the silk group. Significantly lower odds ratios for symptoms were observed in cotton workers who left the cotton mills; risk was also related to years since last worked. Multivariate analysis indicated a trend for higher cumulative exposure to endotoxin in relation to a higher risk for byssinosis. CONCLUSION: Chronic exposure to cotton dust is related to both work specific and non-specific respiratory symptoms. Byssinosis is more strongly associated with exposure to endotoxin than to dust. Cessation of exposure may improve the respiratory health of cotton textile workers; the improvement appears to increase with time since last exposure.

Adult↗
PubMed2003

A longitudinal observation of early pulmonary responses to cotton dust.

AIMS: To examine early adverse pulmonary effects of exposure to cotton dust, and to identify potential risk factors, including atopy for pulmonary responses to cotton dust. METHODS: Spirometry, methacholine challenge testing, and questionnaire; performed among 101 non-smoking newly hired textile workers at baseline (prior to starting work), and at 3, 12, and 18 months after starting work. Concentrations of airborne cotton dust in various work areas were measured at each follow up survey using vertical elutriators. RESULTS: The incidence of non-specific respiratory symptoms was 8% at three months, then diminished afterwards. Substantial acute cross shift drops in FEV(1) at each follow up survey, and longitudinal declines in FVC and FEV(1) after 12 months of exposure were observed. Airway responsiveness to methacholine increased with follow up time, and was more pronounced among atopics. Increasing airway responsiveness was strongly correlated with cross shift drops in FEV(1). In addition, one or more respiratory symptoms at three months was significantly, and pre-existing atopy marginally significantly, associated with cross shift drops in FEV(1) after adjusting for other covariates and confounders. CONCLUSION: Results suggest that non-specific respiratory symptoms, decreasing lung function, and increasing airway responsiveness are early pulmonary responses to cotton dust. In addition, the occurrence of respiratory symptoms and increasing airway responsiveness, as well as atopy, may be important predictors for acute changes in lung function among cotton textile workers.

Adolescent↗
PubMed2002

Reliability of serial urine HCG as a biomarker to detect early pregnancy loss.

BACKGROUND: To examine the reliability of HCG as a biomarker for early pregnancy loss, five experienced researchers independently assessed data from 153 menstrual cycles, determining whether each cycle represented 'no conception,' a 'continuing conception' or a 'conception lost.' METHODS: Urine samples were analysed by immunoradiometric assay using a combination of capture antibodies for the intact heterodimer (B109) and for an epitope common to the beta subunit and the beta core fragment (B204). For each cycle, HCG data were presented as graphs of daily assay results. Summary statistics for HCG assays from 46 women who had undergone bilateral tubal ligation represented baseline values. RESULTS: Pairwise agreement among the assessors for any of the three options ranged from 78-89%. At least three experts agreed for 147 cycles (96%), accounting for 28 conception losses and 19 continuing conceptions. The multi-rater kappa was 0.62 for the conception lost category and 0.68 for continuing conceptions, indicating substantial agreement. CONCLUSION: The main sources of disagreement involved deciding whether there was sufficient information for assessment, interpreting cycle parameters such as cycle length or bleeding event, and interpreting a distinct HCG rise pattern that does not exceed the baseline value obtained from the sterilized women.

Abortion, Spontaneous↗
PubMed2002

Hormesis: the new approach in risk assessment?

Hormesis is a dose-response phenomenon characterized by either a U-shaped or an inverted U-shaped dose response depending on the different end points measured. In a paper in this issue of the journal, Drs Jayjock and Lewis advocate for the application of hormesis in the field of industrial hygiene, and suggest the use of hormesis as a default assumption in the risk assessment process. However, there are many difficulties for the utilization of hormesis in the field of industrial hygiene. Indeed, it is impossible to test the hormesis hypothesis in many commonly employed experimental model systems for end points of public health concern, and the mechanism of low-dose stimulation of hormesis is not clear. Even if hormesis were proven biologically, its assessment is limited due to difficulties of study design, biological markers selection, statistical power considerations, model and end point selection, and risk model approaches.

Animals↗
PubMed2001

Differential association of the codon 72 p53 and GSTM1 polymorphisms on histological subtype of non-small cell lung carcinoma.

Traditionally, non-small cell lung cancer (NSCLC) has been evaluated as a unique entity in genotyping studies. However, recent biological data suggest that different NSCLC subtypes, specifically adenocarcinomas (AC) and squamous cell carcinomas (SCC), differentially alter cancer behavior. Several studies have associated a p53 polymorphism at codon 72 with NSCLC susceptibility. This study investigated whether different p53 genotypes altered the overall risk of developing AC versus SCC. Polymorphisms in metabolizing enzymes, together with prolonged exposure to tobacco carcinogens, can result in accumulation of DNA damage; these effects may potentiate the effects of subtle differences in p53 function. Thus, interactions between polymorphisms of p53 and either GSTM1 or GSTT1 were also evaluated. We analyzed 1168 incident lung cancer cases and 1256 control subjects using multiple logistic regression. Histological data were available for 1144 cases (98%): 585 with AC, 284 with SCC, and 275 with other histological subtypes (large cell, small cell, mixed, and other). An increase in the NSCLC risk posed by the p53 Pro allele (versus Arg/Arg) was seen in AC compared with controls [adjusted odds ratio (OR), 1.36; 95% confidence interval (CI), 1.1-1.7] but not in SCC (adjusted OR, 1.04; 95% CI, 0.8-1.4). Among AC and SCC cancer patients, individuals with the GSTM1-null genotype had an OR of 1.80 (95% CI, 1.1-2.8; case-only analysis) of having AC versus SCC if they also carried a p53 Pro allele. We conclude that different genotype combinations of p53 and GSTM1 increase the risk of developing specific histological subtypes of NSCLC.

Adenocarcinoma↗
PubMed2001

Association of heart rate variability with occupational and environmental exposure to particulate air pollution.

BACKGROUND: Airborne particulate matter has been linked to excess morbidity and mortality. Recent attention has focused on the effects of particulate exposure on cardiac autonomic control. Inhaled particulates may affect the autonomic nervous system either directly, by eliciting a sympathetic stress response, or indirectly, through inflammatory cytokines produced in the lungs and released into the circulation. METHODS AND RESULTS: This longitudinal study examined the association of particulates </=2.5 microm in diameter (PM(2.5)) with heart rate variability (HRV) in an occupational cohort (N=40). Continuous monitoring of exposure and HR was performed during and away from work. PM(2.5) levels were higher than ambient levels typically reported in Boston, 0.167+/-3.205 mg/m(3) (geometric mean+/-geometric SD). We found a 2.66% decrease (95% CI, -3.75% to -1.58%) in the 5-minute SD of normal RR intervals (SDNN) for every 1 mg/m(3) increase in the 4-hour moving PM(2.5) average and a 1.02% increase (95% CI, 0.59% to 1.46%) in HR after adjusting for potential confounding factors. The decrease in SDNN became larger as the averaging interval increased. CONCLUSIONS: Workers experienced altered cardiac autonomic control after exposure to occupational and environmental PM(2.5). There appears to be either a long-acting (several hours) and a short-acting (several minutes) component to the mechanism of action that may be related to the production of cytokines and the sympathetic stress response, respectively, or a cumulative effect that begins shortly after exposure begins. The clinical significance of these effects in a healthy working population is unclear.

Adult↗
PubMed2001

Tofu consumption and blood lead levels in young Chinese adults.

Tofu is a commonly consumed food in China. Tofu may interfere with lead absorption and retention because of its high calcium content. In this observational study, the authors examined whether dietary tofu intake was associated with blood lead levels among young adults in Shenyang, China. The analyses included 605 men and 550 women who completed baseline questionnaires and had blood lead measurements taken in 1996-1998 as part of a prospective cohort study on reproductive health. Mean blood lead levels were 13.2 microg/dl in men and 10.1 microg/dl in women. Blood lead levels were negatively associated with tofu intake in both genders. A linear trend test showed a 3.7% (0.5-microg/dl) decrease in blood lead level with each higher category of tofu intake (p = 0.003). The highest tofu intake group (> or =750 g/week) had blood lead levels 11.3% lower (95% confidence interval: 4.1, 18.0) than those of the lowest tofu intake group (<250 g/week). In all regression models, data were adjusted for gender, age, height, body mass index, district, cigarette smoking, alcohol drinking, education, occupation, use of vitamin supplements, season, and dietary intake of meat, fish, vegetables, eggs, and milk. In conclusion, the authors found a significant inverse dose-response relation between tofu consumption and blood lead levels in this Chinese population.

Adult↗