Osteoarthritis of the thumb carpometacarpal joint in women and occupational risk factors: a case-control study.

PURPOSE: Among other etiologic factors involved in first carpometacarpal (CMC) osteoarthritis (OA), occupational factors have been postulated as influencing the occurrence of this condition. Very few epidemiologic studies, however, have evaluated this topic. Determining the occupational risk factors is important in proposing preventive measures at the workplace. This case-control study was undertaken to explore whether there was a history of greater exposure to some occupational factors (eg, occupations, hand postures, tasks involving the CMC joint) in women requiring surgery for CMC OA compared with women with no CMC OA noted by history and physical examination. METHODS: The case subjects were 61 women surgically treated for primary CMC OA and the control subjects were 120 aged matched women without history or features of CMC OA. A detailed structured interview was developed to elicit information about age, smoking habits, medical history, lifestyle history, and occupational factors. Occupational factors were based on a detailed history of jobs, coded according to the International Standard Classification of Occupations. For the main occupation/job held for the longest duration and during an average working day, subjects were asked about hand posture or tasks involving requirements presumed to cause a strain or a high load to the CMC joint and about certain work conditions. RESULTS: Of the 61 case and 120 control subjects, 5 and 14, respectively, had never worked. There was no difference between the average number of jobs through the working lifetime of the group of case subjects compared with the group of control subjects. Logistic regression analysis showed that after adjustment for age, smoking status, obesity, CMC OA family history, hysterectomy history, parity, and occasional job, the following occupational factors were risk factors for CMC OA: occupations presumed to be associated with increased risk for CMC OA, occupations involving repetitive thumb use, and jobs perceived by the subject having not enough rest breaks during a day. The group of case subjects had a higher prevalence of hysterectomy history and family CMC OA history compared with the group of control subjects. CONCLUSIONS: Although previous studies have reported that work and exposure history may lack precision as risk factors, our results give further evidence to support the role of certain occupational factors in the occurrence of CMC OA in women. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic II.

Glutathione S-transferase M1 and GST T1 genetic polymorphisms and Raynaud's phenomenon in French vinyl chloride monomer-exposed workers.

Occupational vinyl chloride monomer (VCM) exposure can induce Raynaud's phenomenon (RP). However, not all VCM workers developed RP, which suggests an underlying genetic susceptibility. Genetic polymorphisms of glutathione S-transferases (GSTs), involved in VCM metabolism, have been shown to influence certain VCM-related health effects. We have conducted a case-control study of 58 subjects with RP along with 247 subjects without RP, from a population of 305 French workers exposed or formerly exposed to VCM, to assess any association between GST M1 and GST T1 gene polymorphisms, either separately or in combination, and the presence of RP. None of the GST M1 or GST T1 genotypes were significantly associated with the presence of RP among studied VCM workers. A combination of positive genotypes for both GST M1 and GST T1 was significantly associated with RP presence, compared to the other combinations of genotypes (OR=2.1, 95% CI=1.1-3.8). OR adjusted for age, smoking status, alcohol consumption and history of treated hypertension did not reach significance (OR=2.0, 95% CI=0.9-5.2). None of the GST M1 and GST T1 genotypes seem to contribute separately to the presence of RP, suggesting that they are not, when taken alone, a major determinant of interindividual variability for VCM-induced PR. However, the combination of both positive GST M1 and GST T1 genotypes appears to contribute slightly to susceptibility to RP in VCM-exposed subjects. Nevertheless, our study-the first to examine the role of a genetic component in the occurrence of RP secondary to occupational exposure to a chemical-corroborates the previous considerations that interaction between the genetic constitution and environmental factors is of importance in determining the health-adverse effects of VCM exposure.