Gary M. Liss

Assessment of the relationship between isocyanate exposure levels and occupational asthma.

As part of a previous study, we identified Ontario cases of isocyanate-induced occupational asthma (OA) and the companies at which they worked. The Ontario Ministry of Labour maintained a computerized database including isocyanate air sampling determinations conducted by the Ministry. Within this database, we compared levels of isocyanate concentrations measured at 20 case companies [with compensated isocyanate asthma (OA) claims] with 203 noncase companies, based on air samples collected during the same 4-year period during which the OA claims arose. The proportion of case companies that were ever recorded as having a measured ambient isocyanate concentration of > or = 0.005 ppm was greater than that for noncase companies, for TDI users (43% vs 22%), and for MDI users (40% vs 27%). This reached conventional significance when combined across companies and isocyanate types (50% vs 25%; P < 0.05). This provides some evidence that facilities having OA claims have higher isocyanate exposures than do those without claims.

Can Dupuytren's contracture be work‐related?: Review of the evidence

Dupuytrens contracture (DC) is a disease of the palmar fascia resulting in thickening and contracture of fibrous bands on the palmar surface of the hands and fingers. For decades, a controversy has existed regarding whether acute traumatic injury or cumulative biomechanical work exposure can contribute to the development of this disorder. To address this controversy, this review considers the following questions: Is there evidence that DC is associated with 1) frequent or repetitive manual work; and 2) hand vibration? The published literature was searched for studies meeting the following criteria: 1) in English or having an English abstract; 2) controlled studies; 3) DC an identified health outcome studied; and 4) the study group exposed to repetitive or frequent manual work, vibration, or acute traumatic injury. Relevant non-English articles identified through English abstracts were translated. The validity of studies meeting the selection criteria was assessed using a series of questions adapted from those of Stock [1991: Am J Ind Med 19:87-107]. Studies that met a priori minimum levels of methodologic quality were taken into account to reach conclusions with respect to the above questions. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for each study. Ten studies met the initial selection criteria. Of these, four studies met the criteria for methodologic quality, one addressing the relationship between manual work and DC, and three studies of vibration and DC. No controlled studies of acute trauma and DC were identified. Bennett [1982: Br J Ind Med 39:98-100] found the prevalence of DC at a British PVC bagging and packing plant in which workers were exposed to repetitive manual work to be 5.5 times that at a local plant without packing, and twice the expected prevalence in a U.K. working population previously studied by Early [1962: J Bone Joint Surg 44B:602-613]. DC was observed more frequently among vibration white finger claimants than controls by Thomas and Clarke [1992: J Soc Occup Med 42:155-158] (OR, 2.1; 95% CI, 1.1-3-9), and more frequently among vibration-exposed workers than controls by Bovenzi et al. [1994: Occup Environ Med 51:603-611] (OR, 2.6 95% CI, 1.2-5.5). Cocco et al [1987: Med Lav 78:386-392] found that a history of vibration exposure occurred more frequently among cases of DC than among controls (OR, 2.3; 95% CI, 1.5-4.4). The latter two studies presented some evidence of a dose-response relationship. There is good support for an association between vibration exposure and DC.

Latex allergy in operating room nurses

OBJECTIVE To determine the prevalence of allergy to natural rubber latex and potential crossreacting foods in operating room nurses. METHOD Two hundred forty-seven operating room nurses completed a latex allergy questionnaire. They were questioned about symptoms of latex reactivity and about other allergies particularly to foods that may crossreact with latex. Informed consent was obtained and skin prick testing was performed with natural rubber latex and five latex extracts representing low (0.08 to 0.25 microgram/mL) and high (18 to 106 micrograms/mL) natural rubber latex protein gloves. Skin prick tests were done with four potentially crossreacting foods (banana, avocado, kiwi, and potato), saline, and histamine controls. RESULTS One hundred thirty-five (54.7%) nurses described allergic symptoms they attributed to latex exposure. Of these 12 (4.9%) tested positive to latex extracts alone, 12 (4.9%) tested positive to food extracts alone, and 5 (2.0%) tested positive to both latex and crossreactive foods. Three of the 17 (17.6%) nurses testing positive to latex gave no history of reactivity to latex. Indirect latex ELISA was done on the serum of skin test-positive patients with a 70.6% sensitivity. CONCLUSION Of the nurses tested, 6.9% had positive skin prick tests to latex extracts; 17.6% of these were asymptomatic and 29.4% had associated food positive skin prick tests.

Mortality among Workers Exposed to Carbon Disulfide

Mortality experience was investigated at a plant in Ontario that produced viscose rayon, with carbon disulfide as a main raw material. Work-history records for 279 deceased workers at the plant (plant A) were obtained and compared with those for 511 deceased workers at a pulp and paper plant in the same city (plant B). In a proportional mortality analysis, using as a reference the general population of Ontario, at both plants there were fewer deaths from ischemic heart disease than expected (the proportional mortality ratios [PMRs] were 83 at plant A and 95 at plant B) but more deaths than expected from cerebrovascular disease (PMRs were 115 at plant A and 149 at plant B). In a subgroup of plant A workers who had been employed in high-carbon-disulfide exposure areas, deaths from ischemic heart disease were less than expected (PMR = 82), particularly among those who worked in these areas for more than 5 y. Most deaths occurred among those aged 65 y or more. Mortality from strokes, however, was greater than expected (PMR = 207, p < .05); the excess was confined to workers who died at age 65 y or older (PMR = 229, p = .01). Proportional mortality from strokes was also increased in the pulp workers among those who died at age 65 y or older (PMR = 153). In a case-control analysis, the risk of ischemic heart disease at plant A was slightly less than at plant B (odds ratio (OR] = 0.92, 95% confidence interval [CI] = 0.60-1.42), with no association between risk and years worked in high-carbon-disulfide areas (OR/y = 0.99, 95% CI = 0.94-1.03). Among those who died at age 65 y or older, the risk of stroke in the high-exposure subgroup was (a) increased significantly, compared with other plant A workers (OR = 4.92, 95% CI = 1.66-14.65); and (b) increased slightly, compared with plant B workers (OR = 1.37, 95% CI = 0.83-2.26). These results suggested an unusually low risk of strokes among other plant A workers. The risk of stroke was associated with years in high-carbon-disulfide areas (OR/y = 1.03, 95% CI = 0.96-1.1 0). The observed increase in proportional mortality from strokes may represent a chance finding, but a causal role for exposure cannot be excluded.

Peripheral sensory neuropathy associated with 1,1,1-trichloroethane

A case is described of peripheral sensory neuropathy in a woman who had daily exposure to 1,1,1-trichloroethane, used as a degreasing agent. Although previous reviews of the health effects of 1,1,1-trichloroethane have not indicated long-term neurotoxicity, there are recent animal studies that suggest chronic central neurotoxic effects and previous case reports of peripheral neuropathy in three exposed workers in one plant. Our case provides additional evidence that 1,1,1-trichloroethane exposure may be associated with peripheral sensory neuropathy. Reporting of similar cases is encouraged and investigation of the neurotoxic effects of 1,1,1-trichloroethane is recommended.