Search PubMed⌕ Search

Biomedical subjects

C Hertzman

Publications and source records attributed to C Hertzman.

At least 73 records · Page 4Linked to original sources
PubMed1989

A comparison of exposure estimates by worker raters and industrial hygienists.

The validity and reliability of nine senior sawmill workers' estimates of frequency, duration, and routes of exposure were compared with individual workers' ratings of their own job titles and industrial hygienists' ratings of all job titles in the plant. The reliability of the senior workers' mean exposure estimates [group intraclass correlation coefficient (ICC) = 0.71] compared favorably with those of three pairs of hygienists (group ICC = 0.57, 0.67, and 0.81). The validity of their ratings was assessed in a comparison with urinary chlorophenate measurements representing 92% of the job titles in the sawmill. The senior workers' ratings [coefficient of determination (R2) = 0.22] resembled those of two pairs of industrial hygienists (R2 = 0.24, 0.22) and was significantly greater than that of the third pair (R2 = 0.08). The validity of the self-reports was also low (R2 = 0.15), but the difference was not statistically significant. Senior workers' exposure ratings appear to be as effective as the other methods tested.

Air Pollutants, Occupational↗
PubMed1989

The long good-bye: the great transformation of the British Columbia hospital system.

Much is made of the "threat" an aging population poses to North American health care systems. In this article, we present hospital utilization data from British Columbia over the period 1969-1985, which reinforce our earlier (Barer, Evans, Hertzman, et al. 1987) conclusion: it is not aging per se that poses the threat; rather, it is what we are choosing (through our health care system) to do to and with our elderly. In 1969, British Columbia hospital patients over 65 years of age and staying longer than 60 days accounted for 12.5 percent of all days; by 1985/86, they were accounting for 39 percent. Furthermore, in 1985/86, 1 patient in 200 was using one-quarter of all patient days and dying at the end of the process, and 2 patients in 100 (who stayed over 60 days whether discharged alive or dead) were accounting for almost one-half of all days.

Adolescent↗
PubMed1988

Validity and reliability of a method for retrospective evaluation of chlorophenate exposure in the lumber industry.

This paper describes the validity and reliability of a method to retrospectively assess exposure to antisapstain agents used in sawmills (chlorophenates). The method is based on experienced workers' estimates of exposure for each job title at the sawmill where they work. At a pilot mill, 10 randomly selected workers estimated the frequency and duration of exposures to chlorophenates for all 59 job titles. The reliability of their mean exposure estimates was very high, with an intraclass correlation coefficient for all raters of 0.91 (based on a calculated index of exposure). To assess validity, urinary chlorophenate levels were measured for 86% of the workers at the mill during the summer and/or fall, and compared to experienced workers' estimates of exposure. The correlation between workers' exposure estimates and the urinary chlorophenate levels for each job title were consistently above 0.65 for all analyses and greater than 0.72 when summer and fall urine sample results were averaged. The evidence indicates that the validity and reliability of worker exposure estimates are high enough to justify investigation of the method's generalizability to other sawmills.

Chlorophenols↗
PubMed1987

Aging and health care utilization: new evidence on old fallacies.

The proportion of the population in the older age groups will increase dramatically over the next four decades. Furthermore, current per capita rates of hospital and medical care utilization rise sharply with age beyond the age of about 55. However, demographic trends alone do not imply health care cost increases in excess of what is supportable by normal economic growth. A 'cost crisis' will only occur if per capita rates of utilization among the elderly increase faster than for the general population. In this paper we present some descriptive data from published sources suggesting that this has been the case over the recent past in one Canadian province. The implications for the policy debate over the effects of an aging population are discussed.

Adolescent↗
PubMed1987

Observer perception of skin color in a study of malignant melanoma.

Observer perceptions of skin color with a 15-step skin tone panel were evaluated during an as yet unpublished case-control study of malignant melanoma. Skin color is a risk factor for melanoma, and the skin tone panel was introduced in an effort to reduce its misclassification. Reflectances of the 15 artificial skin tones were measured at four wavelengths with a reflectance spectrophotometer. Six observers each evaluated the skin color of eight study subjects twice under three lighting conditions, and the results were transformed to reflectance values. Components of variance analysis demonstrated that between-subject variability contributed 63% or more of the variance at wave-lengths of 400-600 nm, while observers, light source, observation time, and error contributed 30% or less. At 700 nm, only 25.5% of the variance was due to subjects, indicating lower levels of reliability. Similarly, the correlation of visual and spectrophotometric assessment of skin reflectance was higher at 400-600 nm (r = 0.63-0.71) than at 700 nm (r = 0.41). Thus, the value of the skin tone panel-based assessments depends upon knowledge of which wavelengths most closely relate to the physiologic risk factor. For instance, reflectance at 650-700 nm is a better measure of skin melanin content than reflectance at lower wavelengths. Since the role of melanin as a risk factor remains in doubt, the utility of this technique has yet to be demonstrated. However, data from the case-control study and from this validity and reliability study will allow us to develop an analytic approach that minimizes misclassification of skin color as a confounder.

Analysis of Variance↗
PubMed1987

Upper Ottawa street landfill site health study.

This report describes the design and conduct of two sequential historical prospective morbidity surveys of workers and residents from the Upper Ottawa Street Landfill Site in Hamilton, Ontario. The workers study was carried out first and was a hypothesis-generating study. Workers and controls were administered a health questionnaire, which was followed by an assessment of recall bias through medical chart abstraction. Multiple criteria were used to identify health problems associated with landfill site exposure. Those problems with highest credibility included clusters of respiratory, skin, narcotic, and mood disorders. These formed the hypothesis base in the subsequent health study of residents living adjacent to the landfill site. In that study, the association between mood, narcotic, skin, and respiratory conditions with landfill site exposure was confirmed using the following criteria: strength of association; consistency with the workers study; risk gradient by duration of residence and proximity to the landfill; absence of evidence that less healthy people moved to the area; specificity; and the absence of recall bias. The validity of these associations were reduced by three principal problems: the high refusal rate among the control population; socioeconomic status differences between the study groups; and the fact that the conditions found in excess were imprecisely defined and potentially interchangeable with other conditions. Offsetting these problems were the multiple criteria used to assess each hypothesis, which were applied according to present rules. Evidence is presented that supports the hypothesis that vapors, fumes, or particulate matter emanating from the landfill site, as well as direct skin exposure, may have lead to the health problems found in excess. Evidence is also presented supporting the hypothesis that perception of exposure and, therefore, of risk, may explain the results of the study. However, based on the analyses performed, it is the conclusion of the authors that the adverse effects seen were more likely the result of chemical exposure than of perception of risk.

Adult↗
PubMed1987

Longitudinal study of vibration-induced white finger among coastal fallers in British Columbia.

Symptom-based vibration-induced white finger was determined longitudinally from a questionnaire administered to 71 full-time fallers exposed 2-4 h daily to generally heavy (greater than 11 kg), large displacement (greater than 95 cc) chain saws. The prevalence of Raynaud's phenomenon among 55 fallers (after 16 fallers were excluded because of possible confounders) was 51% in 1979-1980. This figure did not differ significantly from the prevalence in 1984-1985 (53%). Among the 28 fallers reporting symptoms in 1979-1980, seven reported no symptoms in 1984-1985, while four indicated improvement in the severity of symptoms resulting in a decreased stage assessment. Evidence for actual recovery was weak because of discrepancies in the symptom reporting. Reported recovery and improvement in the group with symptoms in 1979-1980 was counterbalanced by a significant 30% onset of new symptoms among fallers who were asymptomatic in 1979-1980. Six of the eight fallers reporting new symptoms were exposed only to antivibration saws, a finding suggesting that the type of saws used in the present investigation is not preventing the onset of new disease. Weighted 4-h equivalent acceleration levels from the handlebars of saws commonly used by the cohort group in 1984 ranged from 4.0 to 12.4 m/s2.

British Columbia↗
PubMed1983

Lung cancer in a steel foundry: a search for causation.

Epidemiological studies suggest an association between excess lung cancer risk and work in ferrous foundries. No causative factors have been identified. The foundry environment is complex, and little is known about the health effects of the levels of known or suspected carcinogens present. As a part of an effort to identify causative factors and to assess current risk, an Ames assay of particulate mutagenicity was undertaken. Mutagenic levels were found to exceed those of urban air and distribution findings were consistent with those of a previous epidemiological study that identified high- and low-risk areas within the foundry. The biological significance of these mutagenic levels is unknown but is under study. A mechanism is suggested to explain current and historical findings.

Humans↗
PubMedDate not supplied

Community risk perception and waste management: a comparison of three communities.

Three cross-sectional surveys were conducted in different regions of British Columbia, using a model of risk perception that divides the community into attitudinal and behavioral subgroups based on awareness and concern about waste management facilities. The three communities differed with respect to their levels of both awareness and concern about facilities, either planned for or situated in their region. Surprisingly, the most polarized community, which had nevertheless accepted a facility, rated this facility as more desirable than the other two communities. The unconcerned group in this community felt well informed, was more trusting of siting and operating agencies, and believed that the facility would generate benefits. The concerned group in this community also felt better informed, was more trusting of siting and operating agencies, and believed that its facility would generate benefits, compared with concerned groups in the other two communities. Longitudinal studies of the attitudes driving the siting process are needed to understand how these relationships evolve over time.

Adult↗
PubMedDate not supplied

Identifying environmental health priorities for a whole nation: the use of principal environmental exposure pathways in the Philippines.

This paper presents a novel approach to establishing environmental health priorities for a large society, based upon the concept of principal environmental exposure pathways (PEEPs). Principal environmental exposure pathways extend the concept of a causal pathway backward from health outcome to exposure, then to the industrial, transportation, commercial, or living conditions that gave rise to the pollution of interest. In the Philippines, where the method was developed and used, five PEEPs were identified: an urban air-pollution pathway; a community water-supply pathway; an urban solid-waste pathway; a rural "point-source" pathway; and a pathway whereby fertilizers and pesticides affect food, worker health, and rural water supplies. Characterizing the PEEPs involved pinpointing the populations at risk necessary to estimate the burden of morbidity and mortality related to each as well as identifying the health outcomes that were experienced by those exposed along each pathway or that they could be expected to experience; determining where adequate health-outcome information was available or absent; where exposure sources were or were not adequately identified; where there were significant gaps in agency responsibilities; where new data flows were needed; and where things could have been improved by improving inter-agency cooperation. The most important success of the PEEP method was to reduce the "problem of everything" in a complex country of 65 million people to a small and manageable number of priority environmental exposures.

Air Pollution↗
PubMedDate not supplied

Childhood lead exposure in Trail revisited.

We sought to identify modifiable determinants of elevated blood lead levels in preschool children; to compare the current situation with past information; to determine historical trends in environmental lead contamination in Trail; and to find a basis for identifying appropriate precautions and protection against future lead exposure. In Phase 1, blood samples were drawn from all children aged 2 to 5. In Phase 2, children in the highest and lowest quartile of blood leads were surveyed by questionnaire. Environmental samples of drinking water, paint, housedust, soil and vegetables were taken from their residences, and soil samples were collected from nearby parks. The average blood lead level was 13.8 micrograms/dl, range 4 to 30 micrograms/dl. This is approximately 40% lower than in 1975, when a previous survey was done, but is high compared to other places in Canada. The study of environmental determinants of lead revealed that soil lead levels and, secondarily, housedust lead levels are the principal determinants of high blood lead. Children with high blood leads also tended to concentrate in neighbourhoods near the lead-zinc smelter.

British Columbia↗
PubMedDate not supplied

Fatalities among British Columbia fallers and buckers 1981-7.

In Canada, the forest industry has the highest rate of lost time injury (161 per thousand workers in 1986) and has the highest fatality rate (1.04 per thousand workers in 1986) of all industries. A retrospective case series of fatal accidents occurring among those employed as fallers or buckers in the British Columbia Forest Industry was studied. 87 cases were found and the files of the provincial coroner were accessed to provide data on these accidents. Due to a lack of denominator data, no risk factors could be identified by several hypotheses for future research were developed. These included: the possibility that lack of work experience and young age may play a role in these accidents, the observation that there are "peaks of incidence" just before noon, on Mondays and Thursdays and in January. There was also the surprising finding of the lack of toxicological evidence indicating impairment of any of these workers. Future directions for research are discussed.

Accidents, Occupational↗
PubMedDate not supplied

Sources of dioxins and furans in British Columbia.

A recent Canadian study of the levels of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in adipose tissue suggested higher levels in British Columbians than in other Canadians. This led to concerns about the sources of these compounds in B.C. In this paper, we review scientific publications to generate a list of possible sources of PCDDs and PCDFs. We outline which of these are likely to be found in British Columbia, and develop hypotheses concerning their potential contribution to an individual's "PCDD/PCDF load". Further sampling and analysis of British Columbians' adipose tissue could test hypotheses about occupational and environmental exposures to dioxins and furans.

British Columbia↗
PubMedDate not supplied

Historical employment records as data bases for occupational disease research--a case study.

Historical employment records in the B.C. coastal lumber industry were examined for adequacy for record linkage to the national Mortality Data Base. Employer, union, pension, and health and welfare plan records existed with varying amounts of personal information. The recommended list of identifiers for linkage is extensive. To evaluate the likelihood of successful linkage with the limited identifiers available in the case study, we compared our findings with the INCO-United Steelworkers mortality study carried out by McMaster University. Their evaluation of automated record linkage using limited identifiers compared to intensive direct follow-up of a sample of 1000 indicated a satisfactory rate of follow-up. This suggests that the historical records found in the case study would provide an adequate basis for research using record linkage.

Adult↗
PubMedDate not supplied

Environmental risk analysis: a case study.

Traditional risk analysis which has evolved to fit the requirements of regulatory agencies, is often too time-consuming and cumbersome for specific environmental decision making activities in public health. For instance, the discovery of an old chemical landfill operation may require highly focussed risk information to help make a decision to abandon, decontaminate, or develop the site. This paper presents an alternate approach to risk analysis which is more efficient than traditional methods in assessing the human health risks associated with specific development plans. The method is illustrated with an example of a building site in British Columbia.

Child↗