Krause N; Ragland DR; Greiner BA; Syme SL; Fisher JM. Psychosocial job factors associated with back and neck pain in public transit operators. Scand J Work Environ Health 1997 Jun;23(3):179-86.
ABSTRACT:
OBJECTIVES: This cross-sectional study examined associations
between psychosocial job factors and the prevalence of nondisabling
back and neck pain in professional drivers after physical work
load was taken into account.
METHODS: A total of 1449 transit vehicle operators completed a
medical examination and a questionnaire yielding information on
demographic and anthropometric variables, health status, and physical
and psychosocial job factors. Company records were used to supplement
information on employment history. Physical work load was measured
in life-time years and current weekly hours of professional driving.
The relation of psychosocial factors with back or neck pain was
analyzed by logistic regression models adjusted for past and current
physical work load, vehicle type, age, gender, body height, and
weight.
RESULTS: The main result of this study was that both physical
work load and psychosocial factors were simultaneously and independently
associated with back or neck pain. Psychosocial factors associated
with back or neck pain included extended uninterrupted driving
driving periods, frequency of job problems, high psychosocial
demands, high job dissatisfaction, and low supervisory support.
An analysis of specific job problems is provided which may be
useful in setting priorities for research and intervention efforts
in this high risk occupation.
CONCLUSION: The results provide support for the role of psychosocial
job characteristics in the etiology of back or neck pain in occupational
settings.
Kim SG; Roth JA; Fisher JD; Chung J; Nagabhairu R; Ferrick KJ; Ben-Zur U; Gross J; Furman S. Long-term outcomes and modes of death of patients treated with nonthoracotomy implantable defibrillators. American Journal of Cardiology, 1995 Jun 15, 75(17):1229-32.
Fisher JP; Picard MH; Mikan JS; Fram DB; Fisher JR; Kluger J; Waters DD; Gillam LD. Quantitation of myocardial dysfunction in ischemic heart disease by echocardiographic endocardial surface mapping: correlation with hemodynamic status. American Heart Journal, 1995 Jun, 129(6):1114-21.
Ragland DR; Greiner BA; Krause N; Holman BL; Fisher JM. Occupational and nonoccupational correlates of alcohol consumption in urban transit operators. Prev Med 1995 Nov;24(6):634-45.
ABSTRACT:
BACKGROUND. The influence of occupation and the worksite has
emerged as an important area of study in research on alcohol consumption.
Occupational and nonoccupational factors were studied in relation
to alcohol consumption using data from a 1983-1985 cross-sectional
study of transit operators.
METHODS. A total of 1.853 operators underwent a medical examination
for driver's license renewal (including information on age, ethnicity,
gender, education). Of these operators, 1,448 completed a questionnaire
about occupational (e.g., time of shift, job stressors) and nonoccupational
(e.g., personality, life stressors) factors. From either the medical
examination or the questionnaire, weekly alcohol consumption was
available for 1,820 operators. Variables related to alcohol consumption
in previous studies, or theoretically linked to consumption, were
analyzed in relation to heavy ( > or = 15 drinks/week) and
average weekly consumption.
RESULTS. Heavy and average consumption were both related to several
nonoccupational variables, including demographic (age, ethnicity,
gender, marital status), personality (depression, anger expression),
and life stress variables (i.e., life events). Heavy and average
consumption were also related to several occupational variables,
including job history (number of years driving, specific worksite)
and job stressors. Neither measure was related to subjective job
content (job demand, decision latitude).
CONCLUSIONS. Variability in consumption by demographic factors
among this population reflects that seen in society as a whole.
However, occupational factors may influence consumption, since
consumption was strongly related to (a) specific worksite and
time of shift and (b) reported job stressors. Clarifying the exact
influence of occupational and worksite factors on alcohol consumption
will depend on the convergence of findings from different research
designs (e.g., cross-sectional, longitudinal, ethnographic).
Ragland DR; Hundenski RJ; Holman BL; Fisher JM. Traffic volume and collisions involving transit and nontransit vehicles. Accid Anal Prev 1992 Oct;24(5):547-58NLM CIT.
ABSTRACT:
This study reports an analysis of collisions occurring between public transit vehicles operated by the San Francisco Municipal Railway System (Muni), the public transit agency for the City of San Francisco, and nontransit vehicles. The analysis, focusing on weekday collisions during 1987, demonstrated a strong association between hourly transit collisions rates and hourly traffic volume. The collision rate varied from 0.01 per 1,000 Muni vehicle-hours of operation during the interval 5 A.M. to 6 A.M., a time of very low traffic volume, to 0.93 (approximately 1 collision per 1,000 Muni vehicle-hours of operation) during the interval 5 P.M. to 6 P.M., a time of very high traffic volume. Using a power function to predict either the total number of collisions, or the rate of collisions per 1,000 Muni vehicle-hours, almost 90% of total variation was accounted for by traffic volume. A very similar pattern was found for collisions judged either avoidable or unavoidable. A peak in the collision rate between 2 A.M. and 3 A.M. could not be accounted for by traffic volume alone. That peak occurred in the one-hour interval following the 2 A.M. closing of bars in San Francisco, and was composed entirely of a sharp increase in unavoidable collisions. Increasing traffic volume appeared to operate through two mechanisms: (i) an increase in the number of opportunities for a collision, defined as a quantity proportional to the product of the number of Muni and non-Muni vehicles; (ii) an increase in the probability of a collision occurring between any given pair of vehicles.
Winkleby MA; Ragland DR; Fisher JM; Syme SL. Excess risk of sickness and disease in bus drivers: a review and synthesis of epidemiological studies. Int J Epidemiol 1988 Jun;17(2):255-62.
ABSTRACT:
In an extensive search of available literature, 22 epidemiological studies that have examined health risks of bus drivers were identified. These studies focus on three main disease categories: (1) cardiovascular disease, including hypertension, (2) gastrointestinal illnesses, including peptic ulcer and digestive problems, and (3) musculoskeletal problems including back and neck pain. The studies consistently report that bus drivers have higher raes of mortality, morbidity, and absence due to illness when compared to employees from a wide range of other occupational groups. Increased disease rates have been found for drivers regardless of the use of different research methodologies, measurement techniques and comparison groups. When evaluating the impact of bias on the estimates of risk, it appears likely that findings are conservative: strong systematic selective factors have probably favoured the elimination of those in poorer health both at the time of entry into and exit from the job of bus driving and other sources of bias have most likely caused underestimations of risk. Nevertheless, there remain questions that need careful assessment before firm conclusions can be made about whether increased disease rates result from driving a bus. Such questions, coupled with the consistent findings of heightened risk of disease, make urban bus drivers an appropriate and promising occupational group in which to study further the potential adverse effects of the work environment on employee health.
Sharp DS; Osterloh J; Becker CE; Bernard B; Smith AH; Fisher JM; Syme SL; Holman BL; Johnston T. Blood pressure and blood lead concentration in bus drivers. Environ Health Perspect 1988 Jun;78:131-7.
ABSTRACT:
San Francisco bus drivers have an increased prevalence of hypertension. This study examined relationships between blood lead concentration and blood pressure in 342 drivers. The analysis reported in this study was limited to subjects not on treatment for hypertension (n = 288). Systolic and diastolic pressures varied from 102 to 173 mm Hg and from 61 to 105 mm Hg, respectively. The blood lead concentration varied from 2 to 15 micrograms/dL. The relationship between blood pressure and the logarithm of blood lead concentration was examined using multiple regression analysis. Covariates included age, body mass index, sex, race, and caffeine intake. The largest regression coefficient relating systolic blood pressure and blood lead concentration was 1.8 mm Hg/ln (micrograms/dL) [90% C. I., -1.6, 5.3]. The coefficient for diastolic blood pressure was 2.5 mm Hg/ln (micrograms/dL) [90% C. I., 0.1, 4.9]. These findings suggest effects of lead exposure at lower blood lead concentrations than those concentrations that have previously been linked with increases in blood pressure.
Winkleby MA; Ragland DR; Syme SL; Fisher JM. Heightened risk of hypertension among black males: the masking effects of covariables. Am J Epidemiol 1988 Nov;128(5):1075-83.
ABSTRACT: This study examines the extent to which a set of 10 demographic, behavioral, and medical risk factors explain black/white differences in hypertension. Data are from a cross-sectional examination of San Francisco transit drivers aged 25-65 years surveyed during 1983-1985 as part of an occupational health study. The inherent restriction of the study population to bus drivers and the further restriction to males in this population (764 blacks and 224 whites) controlled for factors related to occupation and sex. Control of 10 additional potential risk factors, including age, education, body mass index, smoking, and intake of caffeine and alcohol was possible in the analytic phase of the study. The unadjusted prevalence of hypertension (systolic blood pressure greater than or equal to 140 mmHg, diastolic blood pressure greater than or equal to 90 mmHg, or current use of antihypertensive medications) was 36.1 per cent for black males compared with 30.8 per cent for white males. The greatest difference in prevalence was observed for black males aged 55-64 years, for whom the prevalence was 46 per cent higher than for white males the same age. Despite higher rates of hypertension, blacks in all age groups exhibited lower levels of most major risk factors for hypertension. As a result, the independent effect of race on hypertension was increased rather than attenuated when the 10 covariables were taken into account (odds ratio of 1.27 in the unadjusted analysis, increasing to 1.54 in the adjusted, multivariate analysis). That this set of risk factors did not explain the higher rates of hypertension among blacks suggests that racial differences may arise from as yet unrecognized environmental and/or individual factors. The results also indicate that the association between race and blood pressure may have been underestimated in past studies that have relied on unadjusted analyses, in which negative confounding or masking effects of covariables have not been considered.
Ragland DR; Winkleby MA; Schwalbe J; Holman BL; Morse L; Syme SL; Fisher JM. Prevalence of hypertension in bus drivers. Int J Epidemiol 1987 Jun;16(2):208-14.
ABSTRACT:
This paper reports the results of a cross-sectional study conducted to evaluate the prevalence of hypertension in 1500 black and white male bus drivers from a large urban transit system in the US. Data for this study were compiled from the files of an occupational health clinic which conducts biennial medical examinations for drivers' license renewal. To test whether prevalence of hypertension was higher among bus drivers than among employed individuals in general, drivers were compared to three groups: individuals from both a national and local health survey and individuals undergoing baseline health examinations prior to employment as bus drivers. After adjustment for age and race, hypertension rates for bus drivers were significantly greater than rates for each of the three comparison groups. These findings support previous results from international studies of bus drivers suggesting that exposure to the occupation of driving a bus may carry increased health risk. This research has expanded into an on-going study which has the goals of clarifying the extent of hypertension in bus drivers and identifying specific behavioural and occupational factors that may be responsible for increased risk of cardiovascular disease.