Tohr Nilsson

Increased mortality in COPD among construction workers exposed to inorganic dust

The aim of this study was to find out if occupational exposure to dust, fumes or gases, especially among never-smokers, increased the mortality from chronic obstructive pulmonary disease (COPD). A cohort of 317,629 Swedish male construction workers was followed from 1971 to 1999. Exposure to inorganic dust (asbestos, man-made mineral fibres, dust from cement, concrete and quartz), gases and irritants (epoxy resins, isocyanates and organic solvents), fumes (asphalt fumes, diesel exhaust and metal fumes), and wood dust was based on a job-exposure matrix. An internal control group with “unexposed” construction workers was used, and the analyses were adjusted for age and smoking. When all subjects were analysed, there was an increased mortality from COPD among those with any airborne exposure (relative risk 1.12 (95% confidence interval (CI) 1.03–1.22)). In a Poisson regression model, including smoking, age and the major exposure groups, exposure to inorganic dust was associated with an increased risk (hazard ratio (HR) 1.10 (95% CI 1.06–1.14)), especially among never-smokers (HR 2.30 (95% CI 1.07–4.96)). The fraction of COPD among the exposed attributable to any airborne exposure was estimated as 10.7% overall and 52.6% among never-smokers. In conclusion, occupational exposure among construction workers increases mortality due to chronic obstructive pulmonary disease, even among never-smokers.

Occupational exposure to particulate air pollution and mortality due to ischaemic heart disease and cerebrovascular disease.

Objectives: A growing number of epidemiological studies are showing that ambient exposure to particulate matter air pollution is a risk factor for cardiovascular disease; however, whether occupational exposure increases this risk is not clear. The aim of the present study was to examine whether occupational exposure to particulate air pollution increases the risk for ischaemic heart disease and cerebrovascular disease. Methods: The study population was a cohort of 176 309 occupationally exposed Swedish male construction workers and 71 778 unexposed male construction workers. The definition of exposure to inorganic dust (asbestos, man-made mineral fibres, dust from cement, concrete and quartz), wood dust, fumes (metal fumes, asphalt fumes and diesel exhaust) and gases and irritants (organic solvents and reactive chemicals) was based on a job-exposure matrix with focus on exposure in the mid-1970s. The cohort was followed from 1971 to 2002 with regard to mortality to ischaemic heart disease and cerebrovascular disease. Relative risks (RR) were obtained by the person-years method and from Poisson regression models adjusting for baseline values of blood pressure, body mass index, age and smoking habits. Results: Any occupational particulate air pollution was associated with an increased risk for ischemic heart disease (RR 1.13, 95% CI 1.07 to 1.19), but there was no increased risk for cerebrovascular disease (RR 0.97, 95% CI 0.88 to 1.07). There was an increased risk for ischaemic heart disease and exposure to inorganic dust (RR 1.07, 95% CI 1.03 to 1.12) and exposure to fumes (RR 1.05, 95% CI 1.00 to 1.10), especially diesel exhaust (RR 1.18, 95% CI 1.13 to 1.24). There was no significantly increased risk for cerebrovascular disease and exposure to inorganic dust, fumes or wood dust. Conclusions: Occupational exposure to particulate air pollution, especially diesel exhaust, among construction workers increases the risk for ischaemic heart disease.

Association of boiled and filtered coffee with incidence of first nonfatal myocardial infarction: the SHEEP and the VHEEP study

Abstract.  Hammar N, Andersson T, Alfredsson L, Reuterwall C, Nilsson T, Hallqvist J, Knutsson A, Ahlbom A (Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Stockholm Center of Public Health, Stockholm, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Västernorrland County Council, Sundsvall, Division of Social Medicine, Karolinska Institutet, Stockholm, Norrland University Hospital, Umeå, Sweden) Association of boiled and filtered coffee with incidence of first nonfatal myocardial infarction: the SHEEP and the VHEEP study. J Intern Med 2003; 253: 653–659.

Risk assessment of vibration exposure and white fingers among platers

SummaryThe dose-response relationship between vibration exposure and vascular disorders in the hands was examined in platers. The study was based on a cross section of 89 platers and 61 office workers divided according to exposure to vibration into four groups. Vibration exposure was assessed by measuring the acceleration intensity on a sample of tools, together with both subjective rating and objective measurements of the exposure time. The frequency-weighted energy equivalent acceleration for 4 h was 4.6–4.7 m/s2. The point prevalence of white fingers was 42% for the plater category currently exposed with an odds ratio of 85. The time laps before contraction of white fingers (latency time) was four years for the 10th percentile, and was shorter than predicted according to the ISO-5349 standard. The prevalence of white finger symptoms staged according to the Taylor-Pelmear scale was comparable to the prevalences according to the Stockholm Workshop Scale. Vibration exposure was the dominant source of white fingers and each year of vibration exposure increased the odds ratio for white fingers by 11%. Distal circulation in the hands was assessed by a timed Allen test. The odds ratio for a positive Allen test was higher for the workers exposed to vibration compared to the non-exposed workers. The use of the timed Allen test is suggested in the clinical examination for vibration white fingers. The observed high risk for contracting white fingers could be prevented by exposure level reduction and/or restriction of exposure duration.

Neuromusculoskeletal disorders in the neck and upper extremities among drivers of all-terrain vehicles – a case series

BackgroundThe purpose of this study was to investigate whether professional drivers of all-terrain vehicles (ATVs) with neck pain have a different array of neuromusculoskeletal disorders in the neck and upper extremities than a referent group with neck pain from the general population. It is hypothesized that exposure to shock-type vibration and unfavorable working postures in ATVs have the capacity to cause peripheral nervous lesions.MethodsThis study was based on a case series analyzed according to a case-case comparison design. The study population consisted of 60 male subjects, including professional drivers of forest machines (n = 15), snowmobiles (n = 15), snowgroomers (n = 15) and referents from the general population (n = 15) all of whom had reported neck pain in a questionnaire and underwent an extensive physical examination of the neck and upper extremities. Based on symptom history, symptoms and signs, and in some cases chemical, electroneurographical and radiological findings, subjects were classified as having a nociceptive or neuropathic disorder or a mix of these types.ResultsThe occurrence of asymmetrical and focal neuropathies (peripheral nervous lesion), pure or in a mix with a nociceptive disorder was common among cases in the ATV driver groups (47%–79%). This contrasted with the referents that were less often classified as having asymmetrical and focal neuropathy (27%), but instead had more nociceptive disorders. The difference was most pronounced among drivers of snowgroomers, while drivers of forest machines were more frequently classified as having a nociceptive disorder originating in the muscles.ConclusionThis study found a high prevalence of assymetrical and focal neuropathies among drivers with pain in the neck, operating various ATVs. It seems as if exposure to shock-type whole-body vibration (WBV) and appurtenant unfavorable postures in ATVs may be associated to peripheral nervous lesions.

Variation between seated and standing/walking postures among male and female call centre operators

BackgroundThe dose and time-pattern of sitting has been suggested in public health research to be an important determinant of risk for developing a number of diseases, including cardiovascular disorders and diabetes. The aim of the present study was to assess the time-pattern of seated and standing/walking postures amongst male and female call centre operators, on the basis of whole-shift posture recordings, analysed and described by a number of novel variables describing posture variation.MethodsSeated vs. standing/walking was recorded using dichotomous inclinometers throughout an entire work shift for 43 male and 97 female call centre operators at 16 call centres. Data were analysed using an extensive set of variables describing occurrence of and switches between seated and standing/walking, posture similarity across the day, and compliance with standard recommendations for computer work.ResultsThe majority of the operators, both male and female, spent more than 80% of the shift in a seated posture with an average of 10.4 switches/hour between seated and standing/walking or vice versa. Females spent, on average, 11% of the day in periods of sustained sitting longer than 1 hour; males 4.6% (p = 0.013). Only 38% and 11% of the operators complied with standard recommendations of getting an uninterrupted break from seated posture of at least 5 or 10 minutes, respectively, within each hour of work. Two thirds of all investigated variables showed coefficients of variation between subjects above 0.5. Since work tasks and contractual break schedules were observed to be essentially similar across operators and across days, this indicates that sedentary behaviours differed substantially between individuals.ConclusionsThe extensive occurrence of uninterrupted seated work indicates that efforts should be made at call centres - and probably in other settings in the office sector - to introduce more physical variation in terms of standing/walking periods during the work day. We suggest the metrics used in this study for quantifying variation in sedentary behaviour to be of interest even for other dichotomous exposures relevant to occupational and public health, for instance physical activity/inactivity.

Comparison of different measures for hand-arm vibration exposure

Abstract Vibration measurements have been done on hand-held tools in a group of 48 platers by evaluating the individual vibration acceleration and absorption of vibration energy. The measurement of the acceleration has been done frequency-weighted and frequency-unweighted in accordance with ISO 5349 and NIOSH (USA) recommendations for hand–arm vibration standards, respectively. The acceleration and the energy absorption have been measured simultaneously in the three orthogonal directions, the latter by using a specially designed adapter. The exposure time has been determined by both subjective assessments and objective measurements. Individual energy-equivalent accelerations and vibration dosages have been calculated from these data. The results show that the type of tool was critical to vibration load intensity when the different measures for determining vibration levels were used. Of the methods used, the evaluation specified by ISO 5349 makes most consideration of low frequencies of vibration ( 200 Hz). The results show a poor correlation between the three methods used. The same was found between mean subjective assessment and objective measurement of the average exposure time. Further studies of the relation between results presented here and generated disturbance will be conducted, which may clarify any exposure–response relationship.

Thermal perception thresholds among young adults exposed to hand-transmitted vibration

IntroductionQuantitative sensory testing assesses non-invasively the function of the sensory pathways from receptors to cortex. Studies of workers exposed to vibration support evidence that neuro-sensory hand-arm vibration syndrome also encompasses neuropathy of the small-diameter nerve fibres.ObjectivesTo assess the risk of disturbed thermal perception developing among young adults exposed to vibration and hand-intensive manual work. The aim also encompasses the study of alternative covariates in small-diameter nerve fibre neuropathy assessment.MethodsThis cross-sectional multi-centre study comprised 202 males and females from vocational school programs in auto mechanics, construction and catering. The testing included a baseline questionnaire, a clinical examination focusing on upper extremity disorders and quantitative somatosensory testing. Thermal perception thresholds were assessed, on both hands, second and fifth digits, using a modified Marstock method for warmth and cold.ResultsReduced thermal perception sensitivity was found for digit II compared to digit V, for females compared to males, and between the two study centres. Subjects exposed to vibration at work showed reduced sensitivity to temperature compared to non-vibration exposed. In univariate analyses odds ratios of 1.06 (95% CI 1.006–1.118) and 1.02 (95% CI 0.971–1.078) for reduced perception to cold for the right and left hands, respectively, was found for vibration. This association was lost in multivariate analyses. The study centre was the strongest confounding influence.ConclusionsSensitivity to temperature appears to be reduced despite the subjects short exposure-time and low exposure to vibration. The effect is small in relation to other confounding factors. A low agreement between the modalities indicates the need for separate tests for cold and warmth. Hand-side, age, stature, and BMI were not important for thermal perception but study centre, gender and choice of digit were. Conventional electro-diagnostic investigations are inadequate for evaluating the status of the small-fibre afferent systems leaving QST of thermal perception as the preferred diagnostic tool.

Symptoms and clinical findings from the musculoskeletal system among operators at a call centre in Sweden--a 10-month follow-up study.

The musculoskeletal health among 57 operators at 1 call centre in Sweden was studied with 10 monthly follow-ups, parallel to a reference group of 1,226 professional computer users in other occupations. Operators at this call centre were more symptom-loaded than the other professional computer users in spite of their younger age and shorter exposure to computer work. Symptoms were long-lasting or recurrent. Muscle tenderness and nerve affections in the neck- shoulder region were the most common specific findings and diagnoses at medical examination of incident symptom cases. More extensive studies should be done on the working conditions and health status among call centre workers.

Incidence of Raynaud's phenomenon in relation to hand-arm vibration exposure among male workers at an engineering plant a cohort study

BackgroundThe objective of this study was to assess the incidence of Raynauds phenomenon in relation to hand-arm vibration exposure in a cohort consisting of male office and manual workers.MethodsThe baseline population consisted of 94 office and 147 manual workers at an engineering plant. Raynauds phenomenon (RP) was assessed at baseline and at follow up (at 5, 10 and 15 years). A retrospective and a prospective cohort analysis of data were done. Hand-arm vibration exposure dose was defined as the product of exposure duration and the weighted hand-arm vibration exposure value according to ISO 5349-1.ResultsThe retrospective/prospective incidence of Raynauds phenomenon was 16/14 per 1000 exposure years among exposed and 2.4/5.0 per 1000 years among the not exposed. The retrospective dose response curve based on 4 dose classes showed that class 2, 3 and 4 had similar response and showed higher incidence than the not-exposed. The dose with RP response to hand-arm vibration corresponded to a 10 year A(8) value between 0.4–1.0 m/s2.ConclusionThe results indicate that the EU directive on an action value for hand-arm vibration of 2.5 m/s2 is not too low. Rather, it suggests that employers should take on actions even at exposure values of 1 m/s2A(8).