A randomised controlled trial on whether a participatory ergonomics intervention could prevent musculoskeletal disorders.

OBJECTIVES: To examine the efficacy of a participatory ergonomics intervention in preventing musculoskeletal disorders among kitchen workers. Participatory ergonomics is commonly recommended to reduce musculoskeletal disorders, but evidence for its effectiveness is sparse. METHODS: A cluster randomised controlled trial among the 504 workers of 119 kitchens in Finland was conducted during 2002-2005. Kitchens were randomised to an intervention (n = 59) and control (n = 60) group. The duration of the intervention that guided the workers to identify strenuous work tasks and to seek solutions for decreasing physical and mental workload, was 11 to 14 months. In total, 402 ergonomic changes were implemented. The main outcome measures were the occurrence of and trouble caused by musculoskeletal pain in seven anatomical sites, local fatigue after work, and sick leave due to musculoskeletal disorders. Individual level data were collected by a questionnaire at baseline and every 3 months during the intervention and 1-year follow-up period. All response rates exceeded 92%. RESULTS: No systematic differences in any outcome variable were found between the intervention and control groups during the intervention or during the 1-year follow-up. CONCLUSIONS: The intervention did not reduce perceived physical work load and no evidence was found for the efficacy of the intervention in preventing musculoskeletal disorders among kitchen workers. It may be that a more comprehensive redesign of work organisation and processes is needed, taking more account of workers' physical and mental resources.

Promotion of work ability, the quality of work and retirement.

In this study, the validity of a model designed to promote the work ability of aging workers was examined. The target areas of work ability promotion were searched for the characteristics that explain work ability the best. In addition, the way work ability relates to the quality of work and retirement was examined. The subjects (n = 1101) participated in the follow-up study on aging Finnish workers in 1992 and 1997. The results consistently supported the model for promoting work ability. All four areas of focus-(i) work demands and the environment; (ii) work organization and the work community; (iii) the promotion of workers' health and functional capacity; and (iv) the promotion of professional competence-proved to be strongly associated with work ability. Good work ability was associated with a high quality of work and the enjoyment of staying in one's job. It also predicted active and meaningful retirement.

The attitudes of occupational health personnel to smoking at work.

Attitudes of occupational health care professionals toward smoking and their activity to address smoking issues were investigated by a questionnaire survey. Data were also collected on employees' exposure to environmental tobacco smoke and on smoking policies that existed in workplaces. Questionnaires were mailed to all occupational health care centers (n = 1,004) in Finland. The prevalence of daily smokers was 9.6% among physicians and 3.6% among nurses; 15% and 11%, respectively smoked occasionally. Smoking restrictions were enforced in more than 70% of all workplaces, but only 3.6% of them had a total smoking ban. Nonsmoking professionals were in favor of smoke-fee workplaces and smoking restrictions significantly more often than their smoking colleagues. Nonsmokers also regarded smoking as a serious problem to the organizational climate of workplaces. Almost half of nonsmoking respondents, but only 11% of daily smokers, would totally ban smoking in workplaces. Although the personal smoking status of the respondent had a strong effect on attitudes to smoking regulations, it did not have a clear influence on interest in discussing smoking issues when seeing patients. Nurses were more active in addressing smoking issues than physicians. Occupational health professionals of large companies reported stricter smoking policies at work than those who represented small enterprises

Time to pregnancy among the wives of men exposed to organic solvents.

OBJECTIVES: To assess whether paternal exposure to organic solvents is associated with decreased fertility. METHODS: A retrospective time to pregnancy study was conducted among men biologically monitored for organic solvents. The workers were classified into exposure categories on the basis of work description and the use of solvents as reported in the questionnaires, and on biological exposure measurements. The relative fecundability density ratios (FDR--an analogue of incidence density ratio of clinically recognised pregnancies) were calculated with discrete proportional hazards regression. RESULTS: After three mailings 316 (72.1%) wives of the monitored men participated. The final study population consisted of 282 couples who did not use contraception at the beginning of pregnancy. The FDRs, adjusted for potential confounders, were 0.80 (95% confidence interval (95% CI) 0.57 to 1.11) and 0.74 (95% CI 0.51 to 1.06) for high or frequent and low or intermediate exposure, respectively. High or frequent and low or intermediate exposure were related to decreased fecundability among primigravida (FDRs 0.36; 95% CI 0.19 to 0.66 and 0.53; 95% CI 0.27 to 1.04) but not among couples with at least one previous pregnancy (FDRs 0.96; 95% CI 0.62 to 1.49 and 0.77; 95% CI 0.47 to 1.24). CONCLUSIONS: The findings of the study provide limited support for the hypothesis that paternal exposure to organic solvents might be associated with decreased fertility. Further studies with careful design are warranted.

Risk of nervous system cancer among workers exposed to lead.

Experimental animal studies suggest that lead compounds may increase the risk of gliomas. To study whether occupational exposure to lead increases the risk, we followed nervous system cancer incidence among 20,741 employees biologically monitored for their blood lead (B-Pb) concentrations. We also performed a nested case-referent study, comprising 26 male cases of nervous system cancer (16 of which had gliomas). Those cases a B-Pb > or = 1.4 mumol/L had a twofold increase in the odds ratio of nervous system cancer as compared with those employees whose B-Pb had not exceeded 0.7 mumol/L. The excess was confined to gliomas (odds ratio 11, 95% confidence interval 1.0 to 630 for B-Pb > or = 1.4 mumol/L; overall P value for trend, 0.037). We obtained lifetime information on exposure and potential confounders for 58% of the cases. The odds ratio of glioma was associated with indices of lifetime exposure to lead, and potential confounders seemed not to explain the effects. The results suggest that there may be an association between occupational lead exposure and the risk of gliomas. No firm conclusions can be drawn because of the small number of cases and loss of material.

Excess lung cancer among workers exposed to lead.

OBJECTIVE: Studies on experimental animals suggest that inorganic lead is a carcinogen. The purpose of the study was to examine whether occupational exposure to lead increases the risk of cancer. METHODS: The study population comprised 20,700 workers who had been biologically monitored for their blood lead (B-Pb) concentrations during 1973-1983. The mortality and cancer incidence rates were followed among the monitored workers and compared with those of the Finnish general population. An internal comparison of the cancer incidence rates was also done between subcohorts formed according to individual B-Pb levels. Questionnaire-based information was also collected on lifetime occupational history and potential confounders, and exposure history was assessed on an individual basis with a nested case-referent design for lung cancer. RESULTS: The internal comparison within the cohort showed a 1.4-fold increase in the overall cancer incidence and a 1.8-fold increase in the incidence of lung cancer among those who had ever had a blood lead level of > or = 1.0 mumol.l-1. In the case-referent study, an increased odds ratio for lung cancer was found for concomitant exposure to lead and engine exhaust. The odds ratio for squamous-cell carcinoma of the lung was increased even when the blood lead level had been slightly elevated. Bias or confounding did not explain the risks. CONCLUSIONS: The results suggest that exposure to lead increases the risk of lung cancer. Co-exposure to engine exhaust and lead may be associated with the risk.

Reduced fertility among women exposed to organic solvents.

A retrospective time-to-pregnancy study was performed among women biologically monitored for exposure to organic solvents. The women were participants in a previous study on spontaneous abortion. They were classified into exposure categories on the basis of work description and the use of solvents as reported in the questionnaires and on biological exposure measurements. Daily or high solvent exposure, adjusted for potential confounders, was significantly associated with reduced fecundability in the discrete proportional hazards analysis (incidence density ratio of clinical pregnancies 0.41; 95% confidence interval [CI] 0.27-0.62). The incidence density ratios were decreased also among workers who were exposed to organic solvents in shoe factories (0.28; CI 0.11-0.71), dry cleaning shops (0.44; CI 0.22-0.86), and in the metal industry (0.58; CI 0.34-0.98). The possible effects of various biases are discussed. The results of the study support the hypothesis that daily or high exposure to organic solvents is associated with reduced fertility. There is a need for safer working methods in industries where organic solvents still are used.

CSF follow-up in HIV-1 infection: intrathecal production of HIV-specific and unspecific IGG, and beta-2-microglobulin increase with duration of HIV-1 infection.

Ninety-nine sequential cerebrospinal fluid (CSF) samples from 28 human immunodeficiency virus-1 (HIV-1)-infected patients were analyzed during the follow-up of 9 months to 4 years. Intrathecal synthesis of HIV-antibodies and IgG (p < 0.01), and the levels of beta-2-microglobulin (beta 2m) in the CSF (p < 0.05) and serum (p < 0.01) increased with duration of HIV-1 infection. No effect of duration of HIV-1 infection was observed on the individual CSF white cell counts and the levels of blood-brain-barrier (BBB) permeability. In 13 patients with HIV-1-associated central nervous system (CNS) disease, the effect of duration was seen as an increase of the individual beta 2m levels in serum (p < 0.01). Moreover, 7 of 9 patients who developed neurological disease or showed its progression during the study increased the level of beta 2m in the CSF. All of them increased the level of beta 2m in serum. In 15 neurologically healthy subjects, the effect of duration was expressed as an increase of the level of individual beta 2m in CSF (p < 0.05) and intrathecal IgG synthesis (p < 0.01). In the AIDS group, the level of beta 2m in the CSF increased, but in less severe stages the dependency of the individual CSF parameters on disease duration was not found. Our results indicate that elevated levels of beta 2m in CSF and serum appear to predict progression of neurological and systemic diseases, respectively. Elevated beta 2m in the CSF of clinically intact individuals may indicate subclinical neurological disease caused by HIV-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of chromosomal aberrations, sister chromatid exchanges and micronuclei among power linesmen with long-term exposure to 50-Hz electromagnetic fields.

Chromosomal aberrations, sister chromatid exchanges (SCEs), replication indices and micronuclei in peripheral blood lymphocytes were analysed among 27 nonsmoking power linesmen with considerable long-term exposure to 50-Hz electromagnetic (EM) fields, and among 27 nonsmoking telephone linesmen serving as a reference group, pairwise matched with the exposed workers for age and geographical region. Blood samples from the two groups were collected, cultured and analysed in parallel. No differences between the groups were observed on analysis of SCEs, replication indices or micronuclei. However, the mean rate of lymphocytes with chromatid-type breaks was higher among the power linesmen (0.96% gaps excluded, 1.41% gaps included) than among the reference group (0.44% and 0.70%, respectively). The excess of aberrant cells was concentrated among those power linesmen who had worked earlier in their life. Although the interpretation is somewhat complicated by the confounding effect of previous smoking, these results suggest that exposure to 50-Hz EM fields is associated with a slight increase in chromatid breaks.

The effect of appraisers in estimating metabolic rate with the Edholm scale.

A study was made of the appraisers' effect on the estimation of metabolic rate with the Edholm scale and a table of the ISO 7243 heat stress standard. The appraisers, five experienced and five inexperienced persons, estimated the metabolic rate of three different work tasks from videotapes. Analysis of variance indicated significant ( [Formula: see text] ) differences in the appraisers' recordings of the activities. The appraisers were grouped according to the similarity of the estimated values they gave. The groups thus contained both experienced and inexperienced appraisers, and it was not possible to classify the appraisers into experienced and inexperienced groups according to their earlier experience. The metabolic rates according to the Edholm scale were higher than according to the ISO 7243 table. The differences in metabolic rates given by the individual observers varied from 38 to 118 W/m(2). The variations in the estimation of metabolic rates were greater when the Edholm scale was used. This variation caused considerable variation also in the predicted mean vote, PMV index. It is recommended that the appraisers be selected carefully, because it is not possible to know whether a randomly selected appraiser is an 'average' or an 'extreme' appraiser without a test. Before conducting extensive field surveys where several appraisers estimate the metabolic rates, it would be useful to arrange training in order to calibrate the levels of the Edholm scale as well as ISO method among the appraisers because training clearly unified the estimation.

Infections and other illnesses of children in day-care centers in Helsinki. I: Incidences and effects of home and day-care center variables.

Illnesses among children attending municipal day-care centers (DCCs) were followed in a prospective study in Helsinki during 1985-1986. The study comprised 1,905 follow-up years among children in 29 DCCs. The mean number of illness periods was 4.9 per follow-up year, 7.9 for those under the age of three years and 3.8 for older children. The corresponding average numbers of days of illness were 23, 39 and 17. The most common diagnoses were upper respiratory tract infections (46.0%), diarrhea (17.2%), otitis media (12.9%), eye infections (4.0%), acute tonsillitis (3.2%), and bronchitis (3.0%). The six most common diagnoses, all infections, caused 86% of periods and 79% of days of illness. The ten most common infectious diseases caused 90.9% of absence periods, surgical operations 1.8%, and injuries 0.8%. In children under three years of age, a small area and volume of a DCC, lack of fully mechanized ventilation, and lack of separate facilities were associated with a higher incidence of one or all of the six most common infections. A large number of children at a DCC and small homes were associated with a high incidence of one or all of the most common infections among both younger and older children. The effects of passive smoking, number of siblings, number of household members, and incomes of families were not statistically significant.

Effect of thymectomy and immunosuppressive therapy on anti-neuroblastoma antibody levels in patients with myasthenia gravis.

Antibodies reacting with human neuroblastoma cells (NBL) are distinct from the "classical" anti-acetylcholine receptor (AChR) antibodies in myasthenia gravis (MG). The influence of therapeutic interventions on serum anti-NBL antibody levels was followed in 42 MG patients. Thymectomy alone was performed in 28 patients while immunosuppressive medication was given to 14 patients out of whom 10 also had a thymectomy. In most patients serum anti-NBL antibody titers declined after thymectomy and/or during immunosuppressive treatment, though individual variations in the antibody response could be observed. Sequential examinations of individual patients revealed an association between the clinical severity of MG and anti-NBL antibody levels. No correlation between the treatment-induced changes of anti-NBL and anti-acetylcholine receptor (AChR) antibody titers could be observed during the follow-up period in MG patients positive for both types of antibodies. These findings further emphasize the immunological complexity of MG. Anti-NBL antibodies represent a pathogenic marker of the disease and display a regulation different from that of the anti-AChR antibodies.

The accuracy of estimating the thermal insulation of clothing ensembles - the effect of appraisers.

The effect of the appraisers on the estimation of the thermal insulation of clothing ensembles was investigated. Nine appraisers, four experienced and five inexperienced, estimated the total thermal insulation by summing the values for individual garments. Lists of individual garments worn by workers were given during thermal comfort measurements carried out in shops and stores during one winter and summer. The beginners estimated the thermal insulation as accurately as the experienced appraisers. There were, however, great individual differences, for which three main reasons were found. Interpolation between the insulation provided by two garments was insufficient, and the insulation of these garments should be checked in more precise tables. Classification of the garments into heavy, medium and light clothing items was not adequate, and garments not listed by the workers confused the estimation given by different appraisers. The effect of error in thermal insulation on the PMV index is negligible if more than one appraiser estimates the thermal insulation and the mean of the estimates is used.

Thyroid function as assessed by routine laboratory tests of workers with long-term lead exposure.

Thyroid function was studied in 176 male workers occupationally exposed to lead. The mean blood lead concentration of the workers was 2.70 (SD 1.15, range 0.70-6.45) mumol/l. The mean duration of lead exposure was 7.6 (range 0.1-20) years. The total thyroxine (T4), free thyroxine (FT4), total triiodothyronine (T3), and thyrotropin concentrations in serum were similar in the workers in the low and high blood lead categories. In regression equations the duration of lead exposure had a weak but significant negative association with T4 and FT4, and this association was particularly pronounced when the analyses were restricted to workers with the most intense lead exposure over time. Thus, the results suggest that thyroid function might be depressed as a result of intense long-term lead exposure.

The desmoid tumor. I. Incidence, sex-, age- and anatomical distribution in the Finnish population.

We have (1) estimated the incidence of desmoid tumor (DT) in the Finnish population, and (2) defined statistically four major age components of the DT with different biological properties. The incidence of the DT, based on admissions to four separate hospitals and on the number of pathological biopsy specimens analyzed at the Central Pathological Laboratory of Helsinki University, is 2.4-4.3 new cases per 10(6) inhabitants per annum. Statistical analysis demonstrated four major age components where the site of the tumor and/or sex of the patient were non-randomly distributed: "juvenile" DT, a predominantly extra-abdominal desmoid tumor of the female sex; "fertile" DT, a nearly exclusively abdominal DT of fertile females; "menopausal" DT, a predominantly abdominal tumor where the sex ratio approaches one:one; and "senescent" DT, where abdominal and extra-abdominal varieties are equally frequently encountered and where the sex ratio of the affected patients is one:one.