Health habits and risk factors among truck drivers visiting a health booth during a trucker trade show.

PURPOSE: The purpose of this report is to provide general information on the personal characteristics, health status, and health interests reported by long-haul truck drivers. DESIGN: A cross-sectional survey was conducted based on a convenience sample. Statistical independence between comparison groups for driver type, age, and gender were tested with the Pearson chi-square test. SETTING: The study population consisted of truck drivers who stopped at one of 65 truck stops participating in a trucker trade show. SUBJECTS: Subjects were 2,945 male self-identified truck drivers and 353 female self-identified truck drivers who visited health booths at the trade show. It was estimated that two thirds of visitors to the health booth participated. MEASURES: A self-administered, close-ended questionnaire recorded the participant's personal characteristics, health status, and health interests. Blood pressure was measured by trained volunteers. RESULTS: A large percentage of male truck drivers smoked cigarettes (54% vs. 30% of U.S. white males), did not exercise regularly (92%), were overweight (50% vs. 25% of U.S. white males), and/or were not aware they had high blood pressure (66% vs. 46% of U.S. population). Also, 23% of surveyed truck drivers tested positive on one measure of alcoholism. CONCLUSIONS: Although a scientific sample frame was not used, the health status and lifestyle observed in this study suggest truck drivers would clearly benefit from a health education and promotion program. The truck stops should be evaluated as a possible setting for such a program.

Health risk communication--a view from within industry.

Health risk communication is discussed in respect to four principles of biomedical ethics: (1) autonomy, the need to protect confidentiality and provide decision-making information; (2) beneficence, an obligation to inform and to develop trust; (3) non-maleficence, not covering up study findings, not over- or underinterpreting data; and (4) justice, helping place risk in proper perspective. The epidemiologist's role in risk communication includes responsible interpretation of data, balanced and non-judgemental risk communication and careful attention to the biologic and population significance of study findings. Potential problem areas for epidemiologists which are discussed include deciding when risk is significant, working for an agency which does not want a communication to take place and the occasional need to violate confidentiality for overriding societal goals. The paper concludes with an example risk communication which illustrates some of the principles covered in the paper.

Potential for misleading associations between exposure and disease when reviewing multiple epidemiologic studies.

In reviewing evidence from multiple epidemiologic studies, a statistical artifact can leave an impression that a relationship exists between an exposure and a disease even if none exists. In this paper, two fundamental properties of probability were applied to hypothetical situations where results from independent studies were combined. It was evident that, even when a cause-effect relationship did not exist, several studies still appeared to confirm the relationship. This statistical artifact was related primarily to the total number of independent studies reviewed and to a lesser degree to the size of a given study. Thus, in examining evidence for a cause-effect relationship from multiple published articles, some studies are likely to show the association and some not, even if no association exists. If only the studies which show the association are considered, without regard to the total number of studies, the reviewer can be misled. This statistical effect is illustrated with an example from the rubber worker literature.

Respiratory symptoms and lung function in habitual heavy smokers of marijuana alone, smokers of marijuana and tobacco, smokers of tobacco alone, and nonsmokers.

To evaluate the possible pulmonary effects of habitual marijuana smoking with and without tobacco, we administered a detailed respiratory and drug use questionnaire and/or lung function tests to young, habitual, heavy smokers of marijuana alone (n = 144) or with tobacco (n = 135) and control subjects of similar age who smoked tobacco alone (n = 70) or were nonsmokers (n = 97). Mean amounts of marijuana and/or tobacco smoked were 49 to 57 joint-years marijuana (average daily number of joints times number of years smoked) and 16 to 22 pack-years of tobacco. Among the smokers of marijuana and/or tobacco, prevalence of chronic cough (18 to 24%), sputum production (20 to 26%), wheeze (25 to 37%) and greater than 1 prolonged acute bronchitic episode during the previous 3 yr (10 to 14%) was significantly higher than in the nonsmokers (p less than 0.05, chi square). No difference in prevalence of chronic cough, sputum production, or wheeze was noted between the marijuana and tobacco smokers, nor were there additive effects of marijuana and tobacco on symptom prevalence. We noted significant worsening effects of marijuana but not to tobacco on specific airway conductance and airway resistance (tests of mainly large airways function) in men and of tobacco but not of marijuana on carbon monoxide diffusing capacity and on closing volume, closing capacity, and the slope of Phase III of the single-breath nitrogen washout curve (tests reflecting mainly small airways function) (p less than 0.03, two-way ANCOVA). No adverse interactive effects of marijuana and tobacco on lung function were found.

Feasibility of epidemiological monitoring for a proposed coal-fired power plant, Ivanpah, California.

The authors were asked to determine the feasibility of conducting epidemiologic monitoring for adverse health impact of emissions from the proposed Ivanpah Coal-Fired Power Plant. The study was required by the licensing agency, and specifically concerned health effects on the surrounding community. No potential occupational effects were considered. The area of concern was limited by the licensing agency to a circle of 50 mile radius around the Ivanpah site. The proposed power plant will be capable of generating 1500 megawatts of electricity utilizing low sulfur western coal. It is designed with stack heights of 500 feet for good dispersion and is planned to be outfitted with the best available stack emission control equipment. To establish whether an epidemiologic study is feasible, one must determine: (1) the size of the population which potentially would be exposed; (2) the pollutants to which that population might be exposed and the expected level of exposure and (3) the known or expected health effects of these pollutants and the frequency of such health outcomes. In addition, as in any epidemiologic study, the choice of a proper comparison group, the acceptability of a study to the population to be monitored and costs of the study in relation to available resources must also be taken into account. The population residing within 20 miles of the site consists of approximately 1,500 people at the present time. This population is not expected to increase significantly, although there is the possibility of growth of a "company town" surrounding the plant. Such an event would clearly alter the feasibility of conducting an epidemiologic study. Air quality modeling was used to predict the exposures to the population from various emissions from the proposed generating station. It was based on worst-case assumptions of wind speed, direction, atmospheric stability and percent sulfur-content coal. While a great many pollutants may result from coal burning, the levels of all pollutants, with the possible exception of ozone, are expected to be much lower than existing standards allow and therefore of little practical concern in the communities near Ivanpah. Since ozone is not a primary pollutant but is of secondary origin, its concentration, given the appropriate conditions, could increase with distance from the plant. None of the expected health outcomes occurs with sufficient frequency to allow the detection, with a reasonable degree of statistical certainty, of any reasonably expected increase in frequency in an epidemiologic study of a population as small as that which is associated with the Ivanpah site.(ABSTRACT TRUNCATED AT 400 WORDS)

Respiratory symptoms of flight attendants during high-altitude flight: possible relation to cabin ozone exposure.

The smaller size and lighter weight of the Boeing 747SP aircraft, introduced into passenger service in 1976, permitted higher-altitude flight than older commercial aircraft and thus potentially greater ozone exposure for those of board. Concerned flight attendants distributed questionnaires relating to symptoms experienced on the Boeing 747SP and/or conventional 747 aircraft to Los Angeles- and New York-based flight attendants. Respondents reported symptoms by frequency and severity and by in-flight and after-flight occurrence. Based on the assessment of three health scientists as to ozone-relatedness, the frequency of "definite" and "probable" ozone-related symptoms of any severity reported by both groups of attendants was significantly associated with 747SP flights (chi-squares: P less than 0.05). After-flight symptoms significantly associated with 747SP experience, although fewer in number than in-flight symptoms, were all in the scientists' "definite" category. In 21 flight attendants who complained of moderate to severe symptoms during 747SP flights, a battery of pulmonary function tests performed approximately two weeks after their last 747SP flight failed to reveal abnormalities. The symptom questionnaire results are consistent with possible exposure of cabin attendants to toxic levels of ozone during the higher-altitude flights of the Boeing 747SP compared to conventional 747 aircraft.

Predicting the risk of cancer at the time of breast biopsy. Variation in the benign to malignant ratio.

The benign to malignant ratio (B:M ratio) among breast biopsies (number of benign breast lesions divided by number of breast cancers) is widely believed to be around 4:1 or 5:1. This belief appears to be based upon experience from the 1950's and 1960's. We investigated possible reasons for the current wide variability of the B:M ratio. A straight line relationship between the log B:M ratio and age exists in our data. The B:M ratio is sensitive to racial differences between patient groups but in only minimally affected by varied histologic inclusion criteria. The overall B:M ratio should not be used to counsel women about their breast cancer risk at the time of biopsy. Age-specific B:M ratios provide a more realistic risk assessment.

Subclinical effects of chronic increased lead absorption--a prospective study. Part IV. Evaluation of heme synthesis effects.

The effects of lead exposure on heme synthesis in workers with subclinical responses and in controls were evaluated. delta-Aminolevulinic acid dehydratase (ALA-d) correlated significantly with blood lead levels in the control group but not with those in the exposed group. Free erythrocyte protoporphyrin correlated significantly with blood lead levels in the exposed group but not with those in the controls and was found to be a good indicator of blood lead history among exposed persons. Hemoglobin values determined at initial employment were not statistically different from those determined during the baseline test for a group of 12 workers with a maximum blood lead level of 86 micrograms/100 ml during their exposure history. The effect such heme inhibition may have on other body functions is uncertain.

Subclinical effects of chronic increased lead absorption--a prospective study. III. Neurologic findings at follow-up examination.

Neurologic examination, nerve conduction testing and electro-oculographic testing have been performed at a baseline examination and a follow-up examination in a group of lead workers with blood lead levels predominantly between 60 and 80 micrograms/dl and in a group of control workers. A statistically significant decreased saccade accuracy measurement in the lead workers compared to the controls was found at both examinations. No other simple test or pattern of findings differentiated between the lead workers and the controls, and the biological significance of the lower saccade accuracy is not clear. Nerve conduction measurements do not appear to be a satisfactory method of detecting subclinical neurologic effects of lead exposure.

Cigarette smoking and lead levels in occupationally exposed lead workers.

One hundred eleven workers at a secondary Pb smelter were surveyed to determine smoking and personal hygiene habits. Fifty-three percent of the smokers had blood Pb levels in excess of 60 micrograms/dl, compared to 31% of nonsmokers (p = 0.02). Among smokers, 66% of "heavy" smokers (greater than or equal to 1 pack a day) had blood Pb levels over 60 micrograms/dl, compared to 39% of the "light" smokers (p = 0.05). Those who kept their cigarettes on their person had a higher proportion of blood Pb greater than 60 micrograms/dl than workers who kept their cigarettes elsewhere (63 versus 36%, respectively; p = 0.08). The difference in blood Pb levels between smokers and nonsmokers may be due in part to direct environmental contamination of cigarettes or impaired lung clearance mechanisms, and could be important in workers with already elevated blood Pb levels.

Quantitative eye tracking tests in lead workers.

A microcomputer system for on-lone analysis of saccadic and smooth-pursuit tracking eye movements is described. Results from a longitudinal study of lead workers and matched controls reveal a consistent decrease in saccade accuracy in the lead workers compared to the controls. Saccade peak velocity and latency and smooth pursuit were not significantly different in the two groups. The abnormal saccade accuracy measurements may indicate a subclinical effect of increased lead absorption, but because of the large scatter in normal values, saccade accuracy measurements are not a reliable indicator of early lead toxicity in a single lead worker.

Subclinical effects of chronic increased lead absorption--a prospective study. II. Results of baseline neurologic testing.

This report summarizes the results of baseline neurologic testing in a group of apparently healthy workers from a secondary lead smelter and a group of controls from nearby aluminum processing plants. The test battery included a standard neurologic examination nerve conduction measurements, quantitative oculomotor function tests and detailed audiologic studies. Lead workers and controls were intermixed so that the examiners were unaware of the status of any individual being tested. Although the lead workers reported significantly more neurologic symptoms than the controls, relatively few differences were found on quantitative neurologic testing. Decreased deep tendon reflexes occured more frequently in the lead workers than in the controls (22% vs. 11%) but the difference was of borderline significance (p=0.06) and other signs of peripheral neuropathy occurred with equal frequency in both groups. The mean motor conduction velocity and sensory latency measurements were not significantly different in the lead workers and in the controls and, of the six oculomotor function measurements, only the mean accuracy of saccadic eye movements was significantly (p less than 0.01) different in the two groups. High frequency hearing loss occurred with equal frequency and severity in both groups, consistent with the level of noise exposure in the lead and control plants.

Subclinical effects of chronic increased lead absorption--a prospective study. I. Study design and analysis of symptoms.

Seventy workers exposed to lead for at least one year and 35 control workers have been enrolled in a prospective study of possible neurologic effects of chronic lead absorption at or below the current standard of 80 microgram per 100 ml whole blood. The study design is described in detail. Initial results of analysis of lead-related symptoms from baseline studies indicate few differences between the exposed and nonexposed workers. The majority of differences were for central nervous system (CNS) symptoms and muscle or joint pain. Little correlation was found between symptom reporting and indices of lead absorption. The evidence suggests that factors other than lead absorption itself may be important in symptom reporting.

Inner-city housing and respiratory disease in children: a pilot study.

This cross-sectional pilot study, designed to examine problems and methodology of studies on the relationship of housing and health, focused on respiratory disease in inner-city black children in Baltimore. Public housing was contrasted to the older row private housing. History of illness, familial, and demographic characteristics were obtained by questionnaire, and a small subsample of children received physical examinations. The condition of the indoor environment was evaluated and measurements of indoor temperature, volume, relative humidity, and carbon monoxide were made. Children in public housing had higher illness rates than those in private housing. Evidence of self-selection into housing type was found. Carbon monoxide levels were found to be greater inside than outside the homes. Preliminary analysis suggests public housing-private-housing classification is less important than other variables, including socioeconomic variables.

Selenium levels in human blood, urine, and hair in response to exposure via drinking water.

Blood, hair, urine, and tap water samples were obtained from participants in a population exposed to varying amounts of selenium via water from home wells. Concentrations of selenium in urine and hair produced significant positive correlations with well-water selenium levels. Blood selenium with well-water selenium did not produce a significant correlation. Urine selenium correlation with hair selenium and urine selenium correlation with blood selenium were found to be significant. No significant correlation for hair selenium with blood selenium was found. We conclude that blood selenium alone is not an adequate monitor of selenium exposure or body burden at levels below chronic toxicity.

A migrant study of adopted Apache children.

Reservation-born Apache children adopted into non-Apache homes off the reservation at an early age were studied for incidence of three illnesses common on the reservation--pneumonia, diarrhea and otitis media. The illness rates were compared with those of non-Apache siblings in the adoptive home and with those of reservation children. Adopted Apache children had more illness than their non-Apache siblings, but less than Apache children on the reservation. Particularly striking was the low rate of multiple episodes of illness for adopted Apaches compared with those on the reservation. Intensive programs are needed to improve living conditions on the reservation.