Clinical factors associated with C-reactive protein in chronic spinal cord injury.

STUDY DESIGN: Cross-sectional study. OBJECTIVES: Determine clinical factors associated with plasma C-reactive protein (CRP) in persons with chronic spinal cord injury (SCI). SETTING: Veterans Affairs Medical Center in Boston, MA, USA. METHODS: Participants provided a blood sample, completed a respiratory health questionnaire and underwent dual X-ray absorptiometry (DXA) to assess total and regional body fat. Linear regression models were used to assess cross-sectional associations with plasma CRP. RESULTS: In multivariable models, factors associated with a higher CRP included a greater BMI, urinary catheter use, a respiratory illness in the past week and non-white race. Mean CRP also increased with decreasing mobility (motorized wheelchair >hand-propelled wheelchair >walk with an assistive device >walk independently). Results were similar when adjusting for percentage android, gynoid, trunk or total fat mass in place of BMI. Level and completeness of SCI was not associated with CRP in multivariable models. CONCLUSIONS: Clinical characteristics common in chronic SCI are associated with plasma CRP. These factors are more important than the level and completeness of SCI and some are potentially modifiable.

Wheelchair use and lipophilic statin medications may influence bone loss in chronic spinal cord injury: findings from the FRASCI-bone loss study.

We identified a protective bone effect at the knee with lipophilic statin use in individuals with chronic spinal cord injury. Lipophilic statin users gained bone at the knee compared to non-users and wheelchair users lost bone compared to walkers. Ambulation and or statins may be effective osteogenic interventions in chronic spinal cord injury (SCI). INTRODUCTION: SCI increases the risk of osteoporosis and low-impact fractures, particularly at the knee. However, during the chronic phase of SCI, the natural history and factors associated with longitudinal change in bone density remain poorly characterized. In this study, we prospectively assessed factors associated with change in bone density over a mean of 21 months in 152 men and women with chronic SCI. METHODS: A mixed model procedure with repeated measures was used to assess predictors of change in bone mineral density (PROC MIXED) at the distal femur and proximal tibia. Factors with a p value of <0.10 in the univariate mixed models, as well as factors that were deemed clinically significant (gender, age, and walking status), were assessed in multivariable models. Factors with a p value of ≤0.05 were included in the final model. RESULTS: We found no association between bone loss and traditional osteoporosis risk factors, including age, gender, body composition, or vitamin D level or status (normal or deficient). In both crude and fully adjusted models, wheelchair users lost bone compared to walkers. Similarly, statin users gained bone compared to nonusers. CONCLUSIONS: The statin finding is supported by reports in the general population where statin use has been associated with a reduction in bone loss and fracture risk. Our results suggest that both walking and statins may be effective osteogenic therapies to mitigate bone loss and prevent osteoporosis in chronic SCI. Our findings also suggest that loss of mechanical loading and/or neuronal factors contribute more to disuse osteoporosis than traditional osteoporosis risk factors.

Adiponectin is associated with bone strength and fracture history in paralyzed men with spinal cord injury.

UNLABELLED: We explored the association between adiponectin levels and bone strength in paralyzed men with spinal cord injury. We found that bone strength was inversely associated with circulating adiponectin levels. Thus, strength estimates and adiponectin levels may improve fracture risk prediction and detection of response to osteogenic therapies following spinal cord injury. PURPOSE: Previous research has demonstrated an inverse relationship between circulating adiponectin and bone mineral density, suggesting that adiponectin may be used as a biomarker for bone health. However, this relationship may reflect indirect effects on bone metabolism via adipose-mediated mechanical pathways rather than the direct effects of adipokines on bone metabolism. Thus, we explored the association between circulating adiponectin levels and bone strength in 27 men with spinal cord injury. METHODS: Plasma adiponectin levels were quantified by ELISA assay. Axial stiffness and maximal load to fracture of the distal femur were quantified via finite element analysis using reconstructed 3D models of volumetric CT scans. We also collected information on timing, location, and cause of previous fractures. RESULTS: Axial stiffness and maximal load were inversely associated with circulating adiponectin levels (R (2) = 0.44, p = 0.01; R (2) = 0.58, p = 0.05) after adjusting for injury duration and lower extremity lean mass. In individuals with post-SCI osteoporotic fractures, distal femur stiffness (p = 0.01) and maximal load (p = 0.005) were lower, and adiponectin was higher (p = 0.04) than those with no fracture history. CONCLUSIONS: Based on these findings, strength estimates may improve fracture risk prediction and detection of response to osteogenic therapies following spinal cord injury. Furthermore, our findings suggest that circulating adiponectin may indeed be a feasible biomarker for bone health and osteoporotic fracture risk in paralyzed individuals with spinal cord injury.

Sclerostin: a candidate biomarker of SCI-induced osteoporosis.

UNLABELLED: We assessed several circulating proteins as candidate biomarkers of bone status in men with chronic spinal cord injury. We report that sclerostin is significantly associated with bone mineral content and bone density at all skeletal sites tested. We found no association between bone and any other tested biomarker. INTRODUCTION: Spinal cord injury results in severe osteoporosis. To date, no circulating biomarker of spinal cord injury (SCI)-induced osteoporosis has been identified. We recently reported that circulating sclerostin is associated with bone density in chronic SCI. In this study, we assessed several circulating proteins as candidate biomarkers of bone in men with chronic SCI. METHODS: We assessed the relationship between bone mineral content or bone density and the following circulating bone-related proteins: sclerostin, DKK-1, soluble receptor activator of nuclear factor kappa B ligand, osteoprotegerin, osteocalcin, and c-telopeptide in 39 men with chronic SCI and 10 men with no SCI. RESULTS: After adjusting for age, lower sclerostin levels were significantly associated with lower bone mineral content and bone density at all skeletal sites tested (p = 0.0002-0.03). No other circulating protein was associated with bone mineral content or bone mineral density (p = 0.18-0.99). CONCLUSION: These findings suggest that circulating sclerostin reflects the severity of bone loss and is a candidate biomarker of osteoporosis severity in chronic SCI.

Chronic obstructive pulmonary disease mortality in railroad workers.

BACKGROUND: There is little information describing the risk of non-malignant respiratory disease and occupational exposure to diesel exhaust. METHODS: US railroad workers have been exposed to diesel exhaust since diesel locomotives were introduced after World War II. In a retrospective cohort study we examined the association of chronic obstructive pulmonary disease (COPD) mortality with years of work in diesel-exposed jobs. To examine the possible confounding effects of smoking, multiple imputation was used to model smoking history. A Cox proportional hazards model was used to estimate an incidence rate ratio, adjusted for age, calendar year, and length of follow-up after leaving work (to reduce bias due to a healthy worker survivor effect). RESULTS: Workers in jobs with diesel exhaust exposure had an increased risk of COPD mortality relative to those in unexposed jobs. Workers hired after the introduction of diesel locomotives had a 2.5% increase in COPD mortality risk for each additional year of work in a diesel-exposed job. This risk was only slightly attenuated after adjustment for imputed smoking history. CONCLUSIONS: These results support an association between occupational exposure to diesel exhaust and COPD mortality.

Urinary naphthalene and phenanthrene as biomarkers of occupational exposure to polycyclic aromatic hydrocarbons.

OBJECTIVES: The study investigated the utility of unmetabolised naphthalene (Nap) and phenanthrene (Phe) in urine as surrogates for exposures to mixtures of polycyclic aromatic hydrocarbons (PAHs). METHODS: The report included workers exposed to diesel exhausts (low PAH exposure level, n = 39) as well as those exposed to emissions from asphalt (medium PAH exposure level, n = 26) and coke ovens (high PAH exposure level, n = 28). Levels of Nap and Phe were measured in urine from each subject using head space-solid phase microextraction and gas chromatography-mass spectrometry. Published levels of airborne Nap, Phe and other PAHs in the coke-producing and aluminium industries were also investigated. RESULTS: In post-shift urine, the highest estimated geometric mean concentrations of Nap and Phe were observed in coke-oven workers (Nap: 2490 ng/l; Phe: 975 ng/l), followed by asphalt workers (Nap: 71.5 ng/l; Phe: 54.3 ng/l), and by diesel-exposed workers (Nap: 17.7 ng/l; Phe: 3.60 ng/l). After subtracting logged background levels of Nap and Phe from the logged post-shift levels of these PAHs in urine, the resulting values (referred to as ln(adjNap) and ln(adjPhe), respectively) were significantly correlated in each group of workers (0.71 < or = Pearson r < or = 0.89), suggesting a common exposure source in each case. Surprisingly, multiple linear regression analysis of ln(adjNap) on ln(adjPhe) showed no significant effect of the source of exposure (coke ovens, asphalt and diesel exhaust) and further suggested that the ratio of urinary Nap/Phe (in natural scale) decreased with increasing exposure levels. These results were corroborated with published data for airborne Nap and Phe in the coke-producing and aluminium industries. The published air measurements also indicated that Nap and Phe levels were proportional to the levels of all combined PAHs in those industries. CONCLUSION: Levels of Nap and Phe in urine reflect airborne exposures to these compounds and are promising surrogates for occupational exposures to PAH mixtures.

Osteoporotic fractures and hospitalization risk in chronic spinal cord injury.

UNLABELLED: Osteoporosis is a well acknowledged complication of spinal cord injury. We report that motor complete spinal cord injury and post-injury alcohol consumption are risk factors for hospitalization for fracture treatment. The clinical assessment did not include osteoporosis diagnosis and treatment considerations, indicating a need for improved clinical protocols. INTRODUCTION: Treatment of osteoporotic long bone fractures often results in lengthy hospitalizations for individuals with spinal cord injury. Clinical features and factors that contribute to hospitalization risk have not previously been described. METHODS: Three hundred and fifteen veterans > or = 1 year after spinal cord injury completed a health questionnaire and underwent clinical exam at study entry. Multivariate Cox regression accounting for repeated events was used to assess longitudinal predictors of fracture-related hospitalizations in Veterans Affairs Medical Centers 1996-2003. RESULTS: One thousand four hundred and eighty-seven hospital admissions occurred among 315 participants, and 39 hospitalizations (2.6%) were for fracture treatment. Median length of stay was 35 days. Fracture-related complications occurred in 53%. Independent risk factors for admission were motor complete versus motor incomplete spinal cord injury (hazard ratio = 3.73, 95% CI = 1.46-10.50). There was a significant linear trend in risk with greater alcohol consumption after injury. Record review indicated that evaluation for osteoporosis was not obtained during these admissions. CONCLUSIONS: Assessed prospectively, hospitalization in Veterans Affairs Medical Centers for low-impact fractures is more common in motor complete spinal cord injury and is associated with greater alcohol use after injury. Osteoporosis diagnosis and treatment considerations were not part of a clinical assessment, indicating the need for improved protocols that might prevent low-impact fractures and related admissions.

Age and motor score predict osteoprotegerin level in chronic spinal cord injury.

OBJECTIVE: Individuals with spinal cord injury (SCI) develop a severe form of osteoporosis below the level of injury that is poorly understood. We conducted a preliminary investigation to assess whether circulating markers of bone turnover and circulating RANKL/OPG levels are related to the severity of SCI, aging, or to differences in mobility (i.e., walking or using a wheelchair). METHODS: Sixty-four caucasian men >or=1.6 years since injury selected based on locomotive mode provided blood samples and completed a health questionnaire at the VA Boston Healthcare System from 10/2003 to 6/2005. Plasma sRANKL, osteoprotegerin (OPG), osteocalcin and carboxyterminal telopeptide of type I collagen (CTx) levels were determined. RESULTS: Increasing age was significantly associated with increased OPG and CTx. Injury severity was predictive of OPG levels, and adjusting for age, participants with cervical motor complete and ASIA C SCI (n=11) had significantly lower mean OPG (46.1 pg/ml) levels than others (63.4 pg/ml). Locomotive mode was not associated with differences in bone markers. CONCLUSIONS: Severe cervical spinal cord injury is associated with decreased circulating OPG levels placing these patients at risk for accelerated bone loss that appears unrelated to locomotive mode.

Occupational exposure to volatile organic compounds and aldehydes in the U.S. trucking industry.

Diesel exhaust is a complex chemical mixture that has been linked to lung cancer mortality in a number of epidemiologic studies. However, the dose-response relationship remains largely undefined, and the specific components responsible for carcinogenicity have not been identified. Although previous focus has been on the particulate phase, diesel exhaust includes a vapor phase of numerous volatile organic compounds (VOCs) and aldehydes that are either known or suspected carcinogens, such as 1,3-butadiene, benzene, and formaldehyde. However, there are relatively few studies that quantify exposure to VOCs and aldehydes in diesel-heavy and other exhaust-related microenvironments. As part of a nationwide assessment of exposure to diesel exhaust in the trucking industry, we collected measurements of VOCs and aldehydes at 15 different U.S. trucking terminals and in city truck drivers (with 6 repeat site visits), observing average shift concentrations in truck cabs and at multiple background and work area locations within each terminal. In this paper, we characterize occupational exposure to 18 different VOCs and aldehydes, as well as relationships with particulate mass (elemental carbon in PM < 1 microm and PM2.5) across locations to determine source characteristics. Our results show that occupational exposure to VOCs and aldehydes varies significantly across the different sampling locations within each terminal, with significantly higher exposures noted in the work environments over background levels (p < 0.01). A structural equation model performed well in predicting terminal exposures to VOCs and aldehydes as a function of job, background levels, weather conditions, proximity to a major road, and geographic location (R2 = 0.2-0.4 work area; R2 = 0.5-0.9 background).

Driver exposure to combustion particles in the U.S. Trucking industry.

A large study of combustion particle exposures for drivers of diesel-powered trucks was conducted in collaboration with an epidemiologic study of lung cancer outcomes for workers in the trucking industry. Three components of diesel exhaust combustion particles (PM(2.5), elemental carbon, and organic carbon) were measured inside the driver cabs of diesel-powered trucks from 36 different trucking terminals across the United States between 2001 and 2005. In-cab particle exposures for drivers assigned to both short and long distance trips were observed, as well as information on the smoking status of the driver, truck characteristics such as age and model, and weather conditions during the sampling session. This article summarizes these findings and describes the relationship between exhaust particles and various determinants of exposure. The results suggest that in-cab particle exposures are positively related to smoking, ambient particle concentrations, truck age, and open windows, with other significant modifying factors such as weather. This study represents the largest and most comprehensive exposure assessment of drivers in the trucking industry, encompassing a 4-year period of observations on diesel and exhaust particle exposures nationwide. The results are relevant not only to the occupational group of truck drivers being examined but also to the general population that live, commute, or work within proximity to diesel-fueled traffic or trucking terminals.

Modeling particle exposure in U.S. trucking terminals.

Multi-tiered sampling approaches are common in environmental and occupational exposure assessment, where exposures for a given individual are often modeled based on simultaneous measurements taken at multiple indoor and outdoor sites. The monitoring data from such studies is hierarchical by design, imposing a complex covariance structure that must be accounted for in order to obtain unbiased estimates of exposure. Statistical methods such as structural equation modeling (SEM) represent a useful alternative to simple linear regression in these cases, providing simultaneous and unbiased predictions of each level of exposure based on a set of covariates specific to the exposure setting. We test the SEM approach using data from a large exposure assessment of diesel and combustion particles in the U.S.trucking industry. The exposure assessment includes data from 36 different trucking terminals across the United States sampled between 2001 and 2005, measuring PM2.5 and its elemental carbon (EC), organic carbon (OC) components, by personal monitoring, and sampling at two indoor work locations and an outdoor "background" location. Using the SEM method, we predict the following: (1) personal exposures as a function of work-related exposure and smoking status; (2) work-related exposure as a function of terminal characteristics, indoor ventilation, job location, and background exposure conditions; and (3) background exposure conditions as a function of weather, nearby source pollution, and other regional differences across terminal sites. The primary advantage of SEMs in this setting is the ability to simultaneously predict exposures at each of the sampling locations, while accounting for the complex covariance structure among the measurements and descriptive variables. The statistically significant results and high R2 values observed from the trucking industry application supports the broader use of this approach in exposure assessment modeling.

A prospective assessment of mortality in chronic spinal cord injury.

STUDY DESIGN: Prospective mortality study. OBJECTIVE: To assess the relationship between comorbid medical conditions and other health-related factors to mortality in chronic spinal cord injury (SCI). SETTING: Boston, MA, USA. METHODS: Between 1994 and 2000, 361 males >/=1 year after injury completed a respiratory health questionnaire and underwent pulmonary function testing. Cause-specific mortality was assessed over a median of 55.6 months (range 0.33-74.4 months) through 12/31/2000 using the National Death Index. RESULTS: At entry, mean (+/-SD) age was 50.6+/-15.0 years (range 23-87) and years since injury was 17.5+/-12.8 years (range 1.0-56.5). Mortality was elevated (observed/expected deaths=37/25.1; SMR=1.47; 95% CI=1.04-2.03) compared to US rates. Risk factors for death were diabetes (RR=2.62; 95% CI=1.19-5.77), heart disease (RR=3.66; 95% CI=1.77-7.78), reduced pulmonary function, and smoking. The most common underlying and contributing causes of death were diseases of the circulatory system (ICD-9 390-459) in 40%, and of the respiratory system in 24% (ICD-9 460-519). CONCLUSIONS: These results suggest that much of the excess mortality in chronic SCI is related to potentially treatable factors. Recognition and treatment of cardiovascular disease, diabetes, and lung disease, together with smoking cessation may substantially reduce mortality in chronic SCI.

Predictors of loud snoring in persons with spinal cord injury.

BACKGROUND: Predictors of loud snoring were examined in a cohort of 197 persons with chronic spinal cord injury (SCI) recruited by advertisement and from a Veterans Affairs Medical Center SCI Service. METHODS: Data were collected on age, marital status, antispasticity medications, duration of injury, level and completeness of injury, stature, and weight. Body mass index (BMI) was calculated for all participants. A health questionnaire was used to collect data on snoring and respiratory history. Habitual snorers were defined as those who reported loud snoring more than 1 night per week. RESULTS: The mean age (+/- SD) was 51.2 +/- 14.8 years, and 84 of 197 (42.6%) were habitual snorers. The most obese research subjects, regardless of antispasticity medication use, were more likely to report snoring, but the risk of snoring was greatest among subjects who were obese and used antispasticity medication. Subjects who used antispasticity medication and had a BMI above the median (> or = 25.3 kg/m2) had a 7-fold risk of reporting snoring compared with subjects below the median who did not use antispasticity medication (P = .001). The greatest risk occurred in those who used diazepam alone or baclofen and diazepam together and had a BMI at or above the median. Subjects who used these medications and had a BMI below the median did not have a significantly increased risk. Neurological motor completeness, level of injury, age, and years since injury were not significant predictors of snoring. CONCLUSION: Because snoring is a marker for obstructive sleep apnea (OSA), the data suggest that in obese individuals with SCI, the use of antispasticity medications may be a risk factor for OSA.

Diesel exhaust exposure and lung cancer: adjustment for the effect of smoking in a retrospective cohort study.

BACKGROUND: The extent that cigarette smoking may confound the relationship between diesel exhaust exposure and lung cancer was assessed in a retrospective cohort study of 55,395 U.S. railroad workers followed from 1959 to 1976. METHODS: The relative risk (RR) of lung cancer due to diesel exhaust was indirectly adjusted using job-specific smoking data from a case-control study of railroad workers who died between 1981-1982 and from a survey of 514 living workers from an active railroad in 1982. Adjustment factors were developed based on the distribution of job-specific smoking rates. RESULTS: The unadjusted RR for lung cancer was 1.58 (95% CI = 1.14-2. 20) for workers aged 40-44 in 1959, who experienced the longest possible duration of exposure, and the smoking adjusted RR was 1.44 (1.01-2.05). CONCLUSIONS: After considering differences in smoking rates between workers exposed and unexposed to diesel exhaust in a relatively large blue-collar cohort, there were still elevated risks of lung cancer in workers in jobs with diesel exhaust exposure.

Vertebral osteomyelitis in paraplegia: incidence, risk factors, clinical picture.

PURPOSE: Because vertebral osteomyelitis (VOM) appears to be relatively common among patients paralyzed due to myelopathy, a population of these patients was surveyed to A) estimate the incidence of VOM, B) identify risk factors, and C) review clinical features. METHOD: The cohort of 537 patients with myelopathy paralyzed prior to January 1, 1989 and subsequently hospitalized at the authors' facility over an 11-year survey period was surveyed. All were male, 93% had a traumatic etiology of paralysis, 50% were > or = 50 years of age, 53% were paraplegic, 54% were motor and sensory complete, and 56% had been paralyzed for 15 years or more. VOM was diagnosed by computerized tomographic demonstration of intervertebral end plate destruction and a positive culture of that site. The relative incidences of VOM were calculated as cases per spinal cord injury (SCI) and general hospitalizations; potential risk factors were assessed by rates of VOM in the myelopathy cohort and clinical features of VOM in these patients were noted. RESULTS: Ten patients with myelopathy developed VOM, an incidence of 20.9 cases/10,000 SCI versus 1.8 cases/10,000 general hospitalizations. The risk ratio was 7.1 (p = .05) for paraplegia, 7.9 (p = .04) for motor and sensory completeness, and 4.4 (p = .06) for diabetes mellitus. The risk ratio for the 3 factors combined was 14.5 (p = .001). Initial clinical presentations were notable for back pain and plain radiographic films revealing paraspinal masses and pleural effusion. CONCLUSIONS: Patients with myelopathy are uniquely at risk for VOM if their paralysis is at the paraplegic level and is motor and sensory complete.

Breathlessness and exercise in spinal cord injury.

After spinal cord injury (SCI), breathlessness during daily activities is common. In 308 individuals with SCI, the authors measured pulmonary function and administered a survey regarding health status, participation in wheelchair athletics, and breathlessness during different activities. The following questions were included: A. Are you troubled by shortness of breath when hurrying on the level or going up a slight hill?; B. Do you have to go slower than people of your own age on the level because of breathlessness?; C. Do you ever have to stop for breath when going at your own pace on the level?; and D. Do you ever have to stop for breath after going about 100 yards on the level? The analysis was restricted to 183 subjects with neurologically motor complete or incomplete SCI who, to get around, used hand-propelled wheelchairs more than 50% of the time. Of these, 56 (31%) reported breathlessness during some types of activities. Subjects with neurologically motor complete cervical or high thoracic SCI (T-6 and above) were more likely to report breathlessness than others (39% compared with 25%, p = .039). Among wheelchair athletes, the prevalence of breathlessness was 8/49 (16%) versus 48/134 (36%) for non-athletes (p = .011). Adjusting for smoking, neurological level, and history of obstructive lung disease, non-athletes were 2.3 times more likely to report breathlessness than athletes were (p = .049 to .075, depending on regression model). This relationship persisted when adjusted for percent predicted forced expiratory volume (FEV1) and maximal expiratory and inspiratory pressures. Therefore in SCI, wheelchair athletes are less likely to report breathlessness than non-athletes, but the mechanism does not appear to be improvement in respiratory muscle performance or pulmonary function.

Breathlessness in spinal cord injury depends on injury level.

Little is known about the prevalence and predictors of breathlessness in individuals with neurologically complete chronic spinal cord injury (SCI). Between December 1992 and September 1993, we mailed a respiratory questionnaire to 1,147 community-based individuals with chronic SCI. The questionnaire included four questions about the presence of breathlessness during activities related to moving about. Of the 485 who replied (42 percent response rate), analysis was limited to adult males with neurologically complete motor injuries who reported using a hand-propelled wheelchair more than 50 percent of the time to get around. Of 130 subjects (33 tetraplegics, 53 high thoracic SCI, 44 lower injury levels), the patients with tetraplegia reported breathlessness more frequently (range for the four questions, 21-33%) than those with high thoracic (range, 9-15%) or lower injury levels (range, 2-11%). For each of the four questions there was a significant trend (p < 0.05) for subjects with higher levels of injury to report the greatest prevalence of breathlessness (tetraplegia > high thoracic > lower). The frequency of breathlessness was greatest in those with neurologically complete cervical injuries, an effect that was independent of obesity, smoking, age, and years since SCI. The mechanisms of breathlessness in SCI are unclear but elucidation might lead to strategies for providing relief.

Maximal expiratory pressures in spinal cord injury using two mouthpieces.

STUDY OBJECTIVE: A technique for assessing expiratory muscle strength is the measurement of maximal expiratory pressure (PEmax). Previous studies have shown that a tube-style mouthpiece yields greater PEmax values than a flange-style mouthpiece because the latter technique is limited by the strength of the buccal muscles. In individuals with weak muscles of exhalation, this limitation may not apply because the strength of their buccal muscles may exceed that of the respiratory muscles. DESIGN: A tube-style mouthpiece and flange-style mouthpiece were used to measure PEmax. The order of the mouthpiece used in testing was alternated between subjects and the greatest values obtained after three efforts were compared. SETTING: Department of Veterans Affairs Medical Center. PARTICIPANTS: Fifty subjects with chronic spinal cord injury without acute medical illnesses recruited from veterans and the community. RESULTS: The mean difference between PEmax(tube) and PEmax(flange) was 20.7+/-26.4 cm H2O (p = 0.0001). Differences were negligible in those with the weakest muscles of exhalation but were substantial even in some quadriplegic subjects. CONCLUSION: Even in individuals with neuromuscular disorders, errors in assessment of expiratory strength occur when a flange-style mouthpiece is used, and we recommend that this technique be abandoned in the measurement of PEmax.

Assessment of stature in spinal cord injury.

Assessment of stature has been a neglected part of the medical assessment of individuals with spinal cord injury (SCI). In past studies of pulmonary function in SCI, it has not been stated how stature was assessed in order to calculate predicted pulmonary function. As part of a study of respiratory function in SCI, we examined the accuracy of self-report of stature and whether upper extremity measurements could be used to predict stature in 88 individuals with SCI. Although armspan and four other upper extremity measurements were significant predictors of length, recalled height was the best predictor. On average, for any value of armspan, an individual with complete SCI was 2.3 cm shorter than an individual with incomplete SCI. Individuals with complete SCI also had greater differences between recalled height and measured length compared with individuals with incomplete SCI, and this difference was not due to age or years since injury. It is likely that differences in bone demineralization account for the differences in length comparing individuals with complete and incomplete SCI. The 95 percent confidence intervals for predicted values of length based on armspan or recalled height were too wide for accurate calculation of predicted pulmonary function. In order to classify accurately the extent of pulmonary function abnormality, we suggest that measurements of supine length be made part of the medical assessment of individuals with SCI.

Occupationally induced airways obstruction.

The studies reviewed in this article indicate the association of occupational exposure to a variety of organic and inorganic dusts and various gases and fumes with chronic bronchitis and decrements of FEV1. Usually an obstructive pattern was noted, although in some occupations a similar decrement in FVC was noted. The effect of smoking on chronic bronchitis, respiratory symptoms, and FEV1 was usually additive, although workers exposed to cotton dust in one study demonstrated an interaction between exposure and smoking, as did a study of a general population sample. In coal workers, exposure to dust in younger workers resulted in a greater decline in lung function than if the exposure occurred in older workers. Studies in coal miners and grain workers further suggest that occupational standards in effect are not sufficient to protect the working population from adverse effects. The magnitude of the effect of occupation on decrement in FEV1 is usually less than cigarette smoking. Studies in coal miners indicate, however, that a minority of workers could be more severely affected by exposure. When considered together with cigarette smoking, additional decrements in lung function because of occupational exposure could contribute to disability. Additional study is needed for better understanding of exposure-response relationships, host factors, potential interaction with cigarette smoking, and pathophysiology of the development of occupationally induced airway disease.