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Biomedical subjects

D C Christiani

Publications and source records attributed to D C Christiani.

At least 145 records · Page 8Linked to original sources
PubMed1994

Women's respiratory health in the cotton textile industry: an analysis of respiratory symptoms in 973 non-smoking female workers.

As part of a 1992 survey of both environmental and occupational determinants of health, 973 non-smoking women aged 20-40 years who were employed in three comparable modern Chinese cotton textile mills were given a questionnaire that included questions on standard respiratory history and symptoms. All women had some potential exposure to cotton dust; mean employment was 8.7 years. Comparisons were made between those with lowest or no current exposure (job classification in administration, quality control, and testing, n = 112) and those in the more heavily exposed classifications (yarn production areas, n = 861). Association of symptoms with job was tested by logistic regression, adjusting for age, passive smoking at home, and the use of home coal burning stoves. Odds ratios for prevalence of current frequent symptoms in those working in production jobs, after adjustment for home exposure to passive tobacco smoke and coal heating, were frequent cough 2.23 (95% confidence interval (95% CI) 1.05-4.75), frequent phlegm 3.24 (1.54-6.84), shortness of breath 4.54 (1.40-14.72), and wheeze 2.96 (1.16-7.55). Nine cases with grade I byssinosis (chest tightness or shortness of breath on return to work after two days off) were found; all were in production jobs. In these non-smoking women textile workers, chronic respiratory symptoms were associated with job category after correction for domestic indoor air quality. These data support evidence for an increased prevalence of respiratory disease in populations exposed to cotton dust.

Adult↗
PubMed1994

Association of rotating shiftwork with preterm births and low birth weight among never smoking women textile workers in China.

1035 married women workers in three modern textile mills in Anhui, China were surveyed to investigate the association of rotating shiftwork with low birth weight and preterm birth in 1992. Information on reproductive health, occupational exposure history, and other covariates including age at pregnancy, time and duration of leave from job since pregnancy, and mill location was obtained by trained nurses with a standardised questionnaire. This analysis was limited to 845 women (887 live births), who were middle or high school graduates, never smokers, and non-alcohol drinkers. About 72% of the women worked an eight day cycle with shift changes every two days throughout pregnancy. Mean gestational age was 38.8 and 39.0 weeks for shift and regular schedule workers, respectively. Multiple linear regression was used to adjust for confounding factors including maternal age at pregnancy, order of live birth, mill location, job title, occupational exposure to dust/gases/fumes, stress, carrying and lifting of heavy loads, working in a squat position, time and duration of leave from the job since pregnancy, and indoor coal combustion for heating. The adjusted difference in gestational age associated with rotating shifts was statistically significant (beta = -0.44 (SE 0.20) weeks.) Mean birth weights were 3248 g and 3338 g for rotating shift workers and regular schedule workers respectively. The estimated effect of rotating shiftwork on birth weight was -79 (SE 42) g. When the analysis was restricted to first order live births or to production workers, the estimated effects of rotating shiftwork on both gestational age and birth weight were significant. The proportions of preterm birth (<37 weeks) and low birth weight (<2500 g), respectively, were 20% and 9% for shift workers and 15% and 6% for regular schedule workers. The adjusted odds ratio of shiftwork was 2.0 (95% CI) 1.1-3.4) for preterm birth and 2.1 (95% CI 1.1-4.1) for low birth weight. This association remained significant when the analysis was restricted to production workers or first order live births.

Adult↗
PubMed1994

Cotton dust exposure, across-shift drop in FEV1, and five-year change in lung function.

To evaluate chronic loss of lung function in cotton dust-exposed workers, a 5-yr follow-up study was performed in Shanghai, China from 1981 to 1986. Workers at a nearby silk thread manufacturing mill were used as a control population. There were 384 cotton textile workers restudied from an original group of 446, and 403 silk workers restudied from the original 468. The presence of byssinosis among retested cotton workers at the time of first survey was 7.3%. The prevalence of byssinosis was 9.7% at the initial survey among those lost to follow-up. No byssinosis was found among control subjects. The mean annual decline in FEV1 was 39.5 ml among cotton workers and 30.6 ml for silk workers (p < 0.05). The greatest annual decrements were found among smoking cotton workers, but nonsmoking cotton workers also lost lung function at a faster rate than silk nonsmokers (annual loss = 33.3 ml versus 24.4 ml, respectively). Autoregressive modeling revealed that after adjustments for age, sex, height, and smoking, cotton dust exposure was significantly associated with decline in FEV1. Moreover, across-shift drop of 5% or more at the time of first survey was predictive of 5-yr decline in FEV1. Cotton workers who had an acute response (5% or greater drop in FEV1 at the time of first survey) suffered a 57.0 ml/yr FEV1 drop compared with a 35.1-ml drop among cotton workers with less acute response at baseline (p < 0.01). Silk workers with or without 5% across-shift drops had similar annual rates of decline (-33.8 ml and -36.1 ml, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Pulmonary function among cotton textile workers. A study of variability in symptom reporting, across-shift drop in FEV1, and longitudinal change.

Longitudinal variability in respiratory responses, including symptom reporting and across-shift change in ventilatory function, were examined in relation to long-term loss of ventilatory function in a group of 447 cotton textile workers in Shanghai, China. The study used a standardized respiratory questionnaire and standardized spirometric testing before and after a work shift on the first day of the workweek. Prediction equations for FEV1 were generated from a group of silk textile workers from the same city. Environmental samples included both vertical elutriated cotton dust and endotoxin levels. There was considerable variability in symptom reporting between the baseline and 5-year follow-up survey for all symptoms. However, subjects who consistently reported symptoms had a significantly accelerated 5-year loss in FEV1 compared with those who never reported symptoms. Subjects with symptoms of chest tightness or dyspnea at one survey lost FEV1 at a rate intermediate between the never or both groups. Moreover, subjects with an across-shift change in FEV1 of more than 5 percent at both surveys had the greatest loss in FEV1 over 5 years (-267 ml) when compared with one-time responders (-224 ml), and nonresponders (-180 ml), though the differences were not significant. Workers with chest tightness and chronic bronchitis in both surveys were overrepresented in the high dust and endotoxin areas. Our results indicate that even with substantial survey-to-survey variability in responses, there is important information contained in both questionnaires and across-shift spirometry. Among cotton workers, consistent responders to either symptom questionnaire or across-shift FEV1 decrements of > or = 5 percent appear to be at increased risk for lung function impairment.

Adult↗
PubMed1994

Carboxyhemoglobin levels in patients with cocaine-related chest pain.

Carboxyhemoglobin (COHb) levels were measured in patients who came to an emergency department complaining of acute chest pain. For subjects not receiving prior oxygen therapy, those with cocaine-related chest pain (n = 10) had a higher mean COHb level than a comparison group (n = 28) with nonischemic chest pain (4.50 +/- 2.40 vs 2.73 +/- 0.66; p < 0.05). Four of the seven (57 percent) who smoked crack had COHb levels greater than 4.5 percent, while only one of six (17 percent) smokers of only tobacco had such a level. These findings suggest an additional mechanism, the formation of COHb, which could aggravate cocaine-induced cardiotoxicity.

Acute Disease↗
PubMed1994

Pseudoelevation of carboxyhemoglobin levels in firefighters.

Carbon monoxide is a common and potentially lethal exposure documented by an elevated carboxyhemoglobin (COHb) level. We conducted an investigation of unexpectedly high carboxyhemoglobin levels in a group of firefighters. Twelve of 34 (35%) nonsmokers tested had levels greater than 4% COHb and 9 of 34 (26%) had levels of 10% or higher. Quadruplicate blood samples from hospital staff and firefighters were sent in duplicate to the original laboratory, which used manual spectrophotometry, and to a second reference facility using a cooximeter. Cooximeter results were lower and also more reproducible. By cooximetry, all 24 nonsmoking firefighters retested had COHb levels less than 3%. Cooximetry is widely available and is the most suitable methodology in clinical situations. Spurious results despite the use of a large reference laboratory argue for the standardization of analytic methods for COHb among laboratories.

Carbon Monoxide Poisoning↗
PubMed1994

Inherited glutathione-S-transferase deficiency is a risk factor for pulmonary asbestosis.

Pulmonary diseases attributable to asbestos exposure constitute a significant public health burden, yet few studies have investigated potential genetic determinants of susceptibility to asbestos-related diseases. The glutathione-S-transferases are a family of conjugating enzymes that both catalyze the detoxification of a variety of potentially cytotoxic electrophilic agents and act in the generation of sulfadipeptide leukotriene inflammatory mediators. The gene encoding glutathione-S-transferase class mu (GSTM-1) is polymorphic; approximately 50% of Caucasian individuals have a homozygous deletion of this gene and do not produce functional enzyme. Glutathione-S-transferase mu (GST-mu) deficiency has been previously reported to be associated with smoking-induced lung cancer. We conducted a cross-sectional study to examine the prevalence of the homozygous deletion for the GSTM-1 gene in members of the carpentry trade occupationally exposed to asbestos. Members of the United Brotherhood of Carpenters and Joiners of America attending their 1991 National Union conference were invited to participate. Each participant was offered a chest X-ray and was asked to complete a comprehensive questionnaire and have their blood drawn. All radiographs were assessed for the presence of pneumoconiosis in a blinded fashion by a National Institute for Occupational Safety and Health-certified International Labor Office "B" reader. Individual GSTM-1 status was determined using polymerase chain reaction methods. Six hundred fifty-eight workers were studied. Of these, 80 (12.2%) had X-ray abnormalities associated with asbestos exposure. Individuals genetically deficient in GST-mu were significantly more likely to have radiographic evidence of nonmalignant asbestos-related disease than those who were not deficient (chi 2 = 5.0; P < 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Progression of chronic obstructive pulmonary disease after multiple episodes of an occupational inhalation fever.

A carding machine operator in a synthetic fabric plant experienced marked symptomatic deterioration of obstructive pulmonary disease after multiple episodes of an occupational inhalation fever. Polytetrafluoroethylene was used in the industrial process and polymer fume fever is suspected as a cause of his febrile illnesses. A state industrial hygiene inspection revealed that major repairs had been performed on an air scrubber system in close proximity to the patient's work area after he had left the plant because of disability. We believe that this case provides further evidence that polymer fume fever is not always a benign, self-limited illness, especially when workers suffer multiple episodes and/or have underlying pulmonary disease.

Air Pollutants, Occupational↗
PubMed1993

Cotton dust and gram-negative bacterial endotoxin correlations in two cotton textile mills.

Exposure to cotton dust is known to cause both acute and chronic respiratory illness. A specific pattern of symptoms called byssinosis is well described to occur among workers in the cotton processing (e.g., yarn preparation) industry. Recent studies have implicated Gram-negative bacterial endotoxin as one of the agents responsible for acute, and possibly chronic, respiratory illness. Laboratory experiments using a model cardroom have found poor correlations between airborne dust and associated endotoxin. This study reports the results of vertical elutriated dust and endotoxin levels in 11 work areas of 2 cotton textile mills in 1986 in Shanghai, China. The overall correlation between dust and endotoxin was strong, rs = 0.66 and 0.79 (p < 0.0001) for mills 1 and 2, respectively. The dust-endotoxin correlation was relatively poor in early yarn preparation in the workshops and improved in the later preparation areas. Our findings suggest that in these mill settings, dust and endotoxin levels may be well correlated in most work areas. Therefore, dust may be a useful index for monitoring populations employed in the cotton textile industry throughout the world. Additional field studies need to be performed which consider the various determinants of dust and endotoxin levels.

Air Pollutants, Occupational↗
PubMed1993

Utility of the complete blood count in routine medical surveillance for ethylene oxide exposure.

The 1984 OSHA Standard for ethylene oxide (EtO) mandates medical surveillance under various circumstances. When performed, medical surveillance for EtO must include a complete blood count (CBC) with differential leukocyte count. This requirement is based on reports of EtO-associated absolute lymphocytosis and other hematologic effects. This paper describes our experiences in providing EtO medical surveillance for a 300 bed hospital over a 6 year period. We observed an apparent relative lymphocytosis which persisted over 3-4 years in sterilization workers with documented TWA personal EtO exposures averaging 0.07 ppm. In addition, three workers had a history of acutely toxic overexposure to EtO as a result of a sterilizer malfunction. These workers became symptomatic following the high accidental overexposure, but did not show absolute lymphocytosis or altered patterns in the relative lymphocytosis. Finally, a cross-sectional comparison of the CBC data from the EtO-exposed workers to data from non-EtO-exposed hospital workers showed no significant differences, ruling out an association of the relative lymphocytosis with EtO exposure. These observations led us to review the basis for the inclusion of the CBC in routine EtO medical surveillance. Our experience, review of the literature on EtO-associated lymphocytosis and anemia, and review of the literature on the use of the CBC with differential as a screening test suggest that the leukocyte differential may not be useful in routine medical surveillance for EtO exposure.

Blood Cell Count↗
PubMed1993

Airborne endotoxin concentrations in various work areas within a cotton mill in Central America.

Gram-negative bacteria and their endotoxins have been shown to cause profound changes in the structure and function of mammalian lungs. Airborne exposures in humans have resulted in bronchoconstriction and symptoms of chest tightness and dyspnea. Cotton dust is often heavily contaminated and endotoxin has been postulated to be the agent in cotton dust which is responsible for the byssinosis syndrome. Previous studies of cotton dust have revealed variable amounts of contamination by bacterial endotoxin, with the variability determined in large part by botanical and climatic characteristics. We report here the results of an environmental study conducted in a cotton mill located in the tropics of Central America using locally grown cotton. Results indicate that airborne endotoxin was present in all yarn preparation and weaving areas and ranged from a low of 18 EU/m3 in weaving to a high of 3138 EU/m3 in opening areas. Airborne levels and the amount of endotoxin per nanogram of dust were not higher than values obtained in temperate climates.

Air Pollutants, Occupational↗
PubMed1993

Asthma risk and occupation as a respiratory therapist.

In the modern hospital environment, many health care workers are exposed to hazardous substances. Among these hazards are respiratory sensitizers, irritants, and infectious agents. A previous cross-sectional study of Rhode Island respiratory therapists reported an excess risk of asthma after entry into that profession. Before the results of that study were published, we conducted a confirmatory mailed questionnaire survey of 2,086 Massachusetts respiratory therapists and 2,030 physical therapists and physical therapy assistants. Neither the survey questionnaire nor the accompanying cover letter revealed the focus of our investigation. A history of physician-diagnosed asthma was reported by 16% of respiratory therapists and 8% of control subjects. When analysis was restricted to those who developed asthma after entry into their profession, respiratory therapists still had a significant excess, 7.4 versus 2.8%. The odds ratio for respiratory therapy was 2.5 (95% Cl, 1.6 to 3.3) after adjustment for age, family history, atopic history, smoking, and gender. These results confirm the previous report of excess risk of asthma among respiratory therapists. This excess risk develops after entry into the profession and does not appear to be explained by bias or confounding. Efforts should be directed to identifying potential agents responsible for this form of occupational asthma.

Adult↗
PubMed1993

Occupational exposures and physician-diagnosed asthma.

Data from a community-based random sample of 3,606 adults 40 to 69 years of age residing in Beijing, China, were used to examine the relationship between occupational exposures to dusts and gases/fumes and physician-diagnosed asthma. The prevalence of asthma was 3.9 percent for men and 3.8 percent for women. After adjusting for sex, age, education, residential areas, indoor coal combustion, and smoking status, the attributable risks of asthma were 1.7 percent and 1.2 percent for dust and gas/fume exposure, respectively. The adjusted odds ratios of asthma for dust and gas/fume exposed groups were 1.6 (95 percent confidence interval [CI], 1.1 to 2.2) and 1.4 (95 percent CI, 0.9 to 2.1), which were independent of sex and smoking status. When subjects were classified into none, dust-only, gas/fume-only, and both-exposure groups, the estimated odds ratios of asthma were 1.3 (95 percent CI, 0.9 to 2.1) in dust-only group, 0.9 (95 percent CI, 0.5 to 1.9) in fume-only group, and 2.1 (95 percent CI, 1.2 to 3.6) in both-exposure group, suggesting a combining effect of the two agents. There was an exposure-response relationship between dust and gas/fume exposures and asthma. In analysis of specific occupational agents, our findings are consistent with previously reported airway effects of organic dusts, but they also suggest that exposure to organic solvents may result in asthma, particularly when combined with dust.

Adult↗
PubMed1992

A participatory workplace health and safety training program for ethylene oxide.

The Occupational Safety and Health Administration (OSHA) has regulated ethylene oxide (EtO) on the basis of its acute toxicity and its potential carcinogenic and reproductive effects since 1971. OSHA's 1984 EtO standard and its 1988 revisions focused new attention on health and safety training and other preventive measures. An EtO health and safety training program for hospital sterilization workers was developed by the staff of an independent occupational and environmental health clinic. Participatory and empowerment training methods were central to the approach. Also included were hands-on, demonstration, interactive presentation, and other methods. An EtO Health and Safety Training Manual was developed based on the training experiences. This paper presents the challenges, benefits, and limitations of incorporating participatory and empowerment approaches in the design, implementation, and evaluation of EtO health and safety training.

Central Supply, Hospital↗
PubMed1992

Occupational lung diseases in the industrializing and industrialized world: commonalities and contrasts: measurement tools.

Research on occupational lung disease has been a growing challenge over the past 4 decades. Exposure to respiratory toxins has increased in many industrializing countries of the world while new and old hazards continue to exist in the industrialized world. The focus of this paper is on measurement tools commonly used in the study of occupational lung diseases. The emphasis is on epidemiology, a discipline which has contributed to the understanding and control of occupational lung disease. An examination of these tools reveals that (1) there are more commonalities than contrasts in available methods; (2) researchers in industrializing settings can contribute much to our understanding of occupational lung diseases; (3) international collaboration is needed in refining measurement tools; and (4) international collaboration should proceed on studies of preventive strategies.

Bronchial Provocation Tests↗
PubMed1992

Exposure-response relationships between occupational exposures and chronic respiratory illness: a community-based study.

Data from a random sample of 3,606 adults 40 to 69 yr of age residing in Beijing, China, were analyzed to investigate the association of reported occupational exposures to dusts and gases/fumes with the prevalence of chronic respiratory symptoms and level of pulmonary function. The prevalence of occupational dust exposure was 32%, and gas or fume exposure, 19%. After we adjusted for age, sex, area of residence, smoking status, coal stove heating, and education, an increased prevalence of chronic phlegm and breathlessness was significantly related to both types of exposures. Chronic cough was significantly related only to dust exposure, and persistent wheeze only to fume exposure. The global estimates of the relative odds of the four symptoms were 1.30 (95% CI [confidence interval] 1.09 to 1.48) and 1.27 (95% CI 1.09 to 1.48), respectively, for dusts and for gases/fumes. These two occupational exposures are associated with chronic respiratory symptoms independent of smoking, gender, and each other. There was an increasing prevalence of each symptom with increasing dust and fume exposure, represented by the index of cumulative exposure duration and exposure intensity. Linear trends for increased prevalence of chronic bronchitis and breathlessness were significant for both exposures, while the linear trend for wheeze was only significant for gases/fumes. Among subjects who did not report using coal stove heating, dust exposure was a significant predictor for FEV1, FEV1/FVC, FEF25-75, and peak expiratory flow rate (PEFR). There was also a significant decrease for FEV1 and FVC with increase of gas/fume exposure levels. Both current and former smokers appeared to be more susceptible to the effect of dusts than the never smokers.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗