R McNamee

Publications of R McNamee

• Work-related sickness absence as reported by UK general practitioners.

  Authors: L Hussey, S Turner, K Thorley, R McNamee, R Agius

  Occupational medicine (Oxford, England). 03/2012; 62(2):105-11.

  Issues surrounding sickness absence are of interest due to growing awareness of the costs to employers and the UK economy, a greater understanding of the interaction between health and work, andIssues surrounding sickness absence are of interest due to growing awareness of the costs to employers and the UK economy, a greater understanding of the interaction between health and work, and increasing evidence that work is beneficial to physical and mental well-being. The Health & Occupation Reporting network in General Practice (THOR-GP) is a national source of information on work-related sickness absence. To assess the factors influencing work-related sickness absence in the UK. General practitioners (GPs) report cases of work-related ill-health via an online web form. Sickness absence information reported with each case was compared by demographic information, diagnosis/symptom and employment factors. Between 2006 and 2009, THOR-GP received 5683 case reports of work-related ill-health; 53% were musculoskeletal diagnoses and 31% were mental ill-health diagnoses. Over half (56%) of cases reported had associated sickness absence. Diagnosis had a highly significant influence on the occurrence of any associated sickness absence. Eighty-one per cent of mental ill-health cases were reported to result in sickness absence compared to 50% of musculoskeletal cases. Public sector employees incurred sickness absence more frequently than those from the private sector. Industries with the highest mental ill-health incidence rates had sickness absence episodes most frequently. Within employment groups, levels of sickness absence were inversely proportional to the level of self-employment. These data reported by GPs with vocational training in occupational medicine may help to inform policy decisions targeting work-related exposures and the management of sickness absence, thereby reducing the UK burden of work-related sickness absence.

• Has European Union legislation to reduce exposure to chromate in cement been effective in reducing the incidence of allergic contact dermatitis attributed to chromate in the UK?

  Authors: S J Stocks, R McNamee, S Turner, M Carder, R M Agius

  Occupational and environmental medicine. 08/2011; 69(2):150-2.

  Hexavalent chromate (chromate) in cement is a well-recognised cause of allergic contact dermatitis (ACD). Consequently in January 2005, following European Union legislation (EU Directive 2003/53/EC),Hexavalent chromate (chromate) in cement is a well-recognised cause of allergic contact dermatitis (ACD). Consequently in January 2005, following European Union legislation (EU Directive 2003/53/EC), the use or supply of cement containing >2 ppm of chromate was prohibited in the UK (COSHH 2004). This analysis of work-related ill-health surveillance aims to evaluate the effectiveness of this legislation. Changes in the incidence of work-related ACD cases returned to The Health and Occupation Reporting network by dermatologists were analysed taking in to account attribution to chromate and occupation. There was a significant decline in the incidence of both ACD attributed to chromate (incidence rate ratio 0.48, 95% CI 0.36 to 0.64) and ACD not-attributed chromate (0.76, 95% CI 0.69 to 0.85) between the time period preceding the EU legislation (2002-2004) and the postlegislation period (2005-2009). However, the decline in ACD attributed to chromate was significantly greater (p=0.006). This decline was further increased in workers potentially exposed to cement (incidence rate ratio 0.37, p=0.001). The majority of the decline in incidence occurred during 2005. The timing of this significant decline in the UK incidence of chromate attributed ACD, and the greater decline in workers potentially exposed to cement strongly suggests that the EU Directive2003/53/EC was successful in reducing exposure to chromate in cement in the UK.

• Occupation and work-related ill-health in UK construction workers.

  Authors: S J Stocks, S Turner, R McNamee, M Carder, L Hussey, R M Agius

  Occupational medicine (Oxford, England). 07/2011; 61(6):407-15.

  Construction workers are at increased risk of work-related ill-health (WRI) worldwide. To compare the incidence of medically reported WRI in occupations within the UK construction industry accordingConstruction workers are at increased risk of work-related ill-health (WRI) worldwide. To compare the incidence of medically reported WRI in occupations within the UK construction industry according to job title. We calculated standardized incidence rate ratios (SRRs) using WRI cases for individual job titles returned to The Health and Occupation Reporting network by clinical specialists and UK population denominators. We counted frequencies of reported causal exposures or tasks reported by clinical specialists, occupational physicians and general practitioners. We found significantly increased incidence of WRI compared with other workers in the same major Standard Occupational Classification, i.e. workers with similar levels of qualifications, training, skills and experience, for skin neoplasia in roofers (SRR 6.3; 95% CI: 3.1-13.1), painters and decorators (2.1; 95% CI: 1.2-3.6) and labourers in building and woodworking trades (labourers, 6.6; 95% CI: 3.2-13.2); contact dermatitis in metal workers (1.4; 95% CI: 1.1-1.7) and labourers (1.6; 95% CI: 1.1-2.3); asthma in welders (3.8; 95% CI: 2.8-5.0); musculoskeletal disorders in welders (1.7; 95% CI: 1.1-2.8), road construction operatives (6.1; 95% CI: 3.8-9.6) and labourers (2.5; 95% CI: 1.7-3.7); long latency respiratory disease (mesothelioma, pneumoconiosis, lung cancer, non-malignant pleural disease) in pipe fitters (4.5; 95% CI: 3.2-6.2), electrical workers (2.7; 95% CI: 2.4-3.2), plumbing and heating engineers (2.3; 95% CI: 1.9-2.7), carpenters and joiners (2.7; 95% CI: 2.3-3.1), scaffolders (12; 95% CI: 8-18) and labourers (3.3; 95% CI: 2.6-4.1). UK construction industry workers have significantly increased risk of WRI. These data in individual construction occupations can be used to inform appropriate targeting of occupational health resources.

• Improving estimates of specialist-diagnosed, work-related respiratory and skin disease.

  Authors: M Carder, R McNamee, S Turner, L Hussey, A Money, R Agius

  Occupational medicine (Oxford, England). 11/2010; 61(1):33-9.

  Work-related skin and respiratory disease still constitute an important part of the work-related ill-health (WRIH) burden of Great Britain (GB). It is therefore important to be able to accuratelyWork-related skin and respiratory disease still constitute an important part of the work-related ill-health (WRIH) burden of Great Britain (GB). It is therefore important to be able to accurately quantify the true incidence of these two groups of disease. To improve the accuracy of the methodology to estimate clinical specialist incidence rates, with a focus on skin and respiratory disease. Specifically, we sought to estimate the number of additional cases not captured by voluntary surveillance through The Health and Occupation Reporting (THOR) network and provide a better estimation of the true incidence of work-related skin and respiratory disease in GB. Cases not captured by THOR in 2005-2007 due to non-participation of eligible clinical specialists and due to <100% response rates by THOR participants were estimated, and the numerator adjusted accordingly. Adjusted incidence rates were calculated using Labour Force Survey data as the denominator. During 2005-2007, 62% of skin cases and 60% of GB respiratory cases were likely to have been captured by THOR. After adjustment, dermatologist-derived incidence rates for skin disease were raised from 9 to 14 per 100,000 employed, while those for respiratory disease were raised from 10 to 17 per 100,000 employed. We have provided a significant improvement in the surveillance-based methodology used to estimate the number of cases of WRIH captured by THOR and hence enabled more accurate estimations of GB incidence rates for clinical specialist-reported WRIH.

• Medically reported work-related ill-health in the UK agricultural sector.

  Authors: S J Stocks, S Turner, M Carder, L Hussey, R McNamee, R M Agius

  Occupational medicine (Oxford, England). 08/2010; 60(5):340-7.

  Self-reported work-related ill-health (WRI) statistics suggest that agricultural workers in the UK are at an increased risk of musculoskeletal disorders (MSD), skin and respiratory disease. However,Self-reported work-related ill-health (WRI) statistics suggest that agricultural workers in the UK are at an increased risk of musculoskeletal disorders (MSD), skin and respiratory disease. However, there is little comprehensive medically reported information on WRI in the UK agricultural sector. Cases of WRI within the UK from 2002 to 2008, as reported to The Health and Occupation Reporting (THOR) network by occupational physicians, clinical specialists and general practitioners, were analysed. Directly standardized incidence rate ratios (SRRs) for the agricultural sector versus all other sectors were calculated for dermatological, musculoskeletal, respiratory and psychological illness, using as the standard population the UK working population as estimated from the Labour Force Survey. During 2002-08, 471 cases within the agricultural sector were reported to THOR (2% of all cases). Based on reports by clinical specialists, male agricultural workers aged <65 years had significantly raised SRRs for MSD (2.3, 95% CI 1.6-3.3), allergic alveolitis (32, 95% CI 19-51), asthma (1.9, 95% CI 1.2-3.0) and skin neoplasia (7.9, 95% CI 5.8-10.9) and a significantly reduced SRR for asbestos-related respiratory disease (0.4, 95% CI 0.2-0.7). Reports of mental ill-health in agricultural workers were low. These medically reported incidence data provide information on WRI in the UK agricultural sector. Consistent with other sources, there are increased risks for asthma, allergic alveolitis and MSD and a reduced risk for mental ill-health. The raised incidence of skin cancer requires confirmation and further comparison with reliable estimates of the incidence in the UK workforce.

• The incidence of medically reported work-related ill health in the UK construction industry.

  Authors: S J Stocks, R McNamee, M Carder, R M Agius

  Occupational and environmental medicine. 08/2010; 67(8):574-6.

  Self-reported work-related ill health (SWI) data show a high incidence of occupational ill health and a high burden of cancer attributable to occupational factors in the UK construction industry.Self-reported work-related ill health (SWI) data show a high incidence of occupational ill health and a high burden of cancer attributable to occupational factors in the UK construction industry. However, there is little information on the incidence of medically reported work-related ill health (WRI) within this industry. This study aims to examine the incidence of WRI within the UK construction industry. Standardised incidence rate ratios (SRRs) were used to compare incidence rates of reports of medically certified work-related ill health returned to The Health and Occupation Reporting network (THOR) within the UK construction industry with all other UK industries combined. Male UK construction industry workers aged under 65 years had significantly raised SRRs for respiratory (3.8, 95% CI 3.5 to 4.2), skin (1.6, 1.4 to 1.8) and musculoskeletal disorders (MSD; 1.9, 1.6 to 2.2). These SRRs were further raised for those working within a construction trade. The increased SRRs for skin disease within male construction industry workers were due to contact dermatitis (1.4, 1.2 to 1.6) and neoplasia (4.2, 3.3 to 5.3). For respiratory disease, the increased SRRs were due to non-malignant pleural disease (7.1, 6.3 to 8.1), mesothelioma (7.1, 6.0 to 8.3), lung cancer (5.4, 3.2 to 8.9) and pneumoconiosis (5.5, 3.7 to 8.0), but the SRRs for asthma (0.09, 0.06 to 0.11) and mental ill health (0.3, 0.1 to 0.4) were significantly reduced. The significantly raised SRRs for medically reported MSD and significantly reduced SRRs for mental ill health in construction workers confirm self-reported UK data. These SRRs provide a baseline of the incidence of WRI in the UK construction industry from which to monitor the effects of changes in policy or exposures.

• The impact of maternal celiac disease on birthweight and preterm birth: a Danish population-based cohort study.

  Authors: A S Khashan, T B Henriksen, P B Mortensen, R McNamee, F P McCarthy, M G Pedersen, L C Kenny

  Human reproduction (Oxford, England). 11/2009;

  BACKGROUND Adverse pregnancy outcomes have been associated with maternal celiac disease (CD). In this study, we investigate the effect of treated and untreated maternal CD on infant birthweight andBACKGROUND Adverse pregnancy outcomes have been associated with maternal celiac disease (CD). In this study, we investigate the effect of treated and untreated maternal CD on infant birthweight and preterm birth. METHODS A population-based cohort study consisted of all singleton live births in Denmark between 1 January 1979 and 31 December 2004 was used. A total of 1 504 342 babies were born to 836 241 mothers during the study period. Of those, 1105 babies were born to women with diagnosed CD and 346 were born to women with undiagnosed CD. Women with diagnosed CD were considered as treated with a gluten free diet while women with undiagnosed CD were considered as untreated. The outcome measures were: birthweight, small for gestational age (SGA: birthweight <10th centile), very small for gestational age (VSGA: birthweight <5th centile) and preterm birth. We compared these measures in treated and untreated women with those of a reference group (no history of CD). RESULTS Women with untreated CD delivered smaller babies [difference = -98 g (95% CI: -130, -67)], with a higher risk of SGA infants [OR = 1.31 (95% CI: 1.06, 1.63)], VSGA infants [OR = 1.54 (95% CI: 1.17, 2.03)] and preterm birth [OR = 1.33 (95% CI: 1.02, 1.72)] compared with women without CD. Women with treated CD had no increased risk of reduced mean birthweight, risk of delivering SGA and VSGA infants or preterm birth compared with women without CD. CONCLUSION Untreated maternal CD increases the risk of reduced birthweight, the risk of delivering SGA and VSGA infants and preterm birth. Diagnosis and presumed treatment of maternal CD with a gluten-free diet appeared to result in a birthweight and preterm birth rate similar to those in women without CD.

• Sex ratio at birth following prenatal maternal exposure to severe life events: a population-based cohort study.

  Authors: A S Khashan, P B Mortensen, R McNamee, P N Baker, K M Abel

  Human reproduction (Oxford, England). 05/2009;

  BACKGROUND A reduction in the sex ratio at birth has been linked to maternal condition during and before pregnancy. A recent study reported an association between maternal exposure to severe lifeBACKGROUND A reduction in the sex ratio at birth has been linked to maternal condition during and before pregnancy. A recent study reported an association between maternal exposure to severe life events and sex ratio at birth using the Danish national register. We attempted to replicate that study using a new Danish cohort. METHODS Mothers of all singleton live births (n = 1.35 million births) in Denmark, between 1 January 1980 and 31 December 2002, were linked to data on their children and partners. The old cohort consisted of babies born between 1980 and 1992 (n = 699 362), whereas the new cohort consisted of babies born between 1993 and 2002 (n = 633 451). We defined exposure as death or serious illness in older children and partners in the first trimester or in the 6 months before conception. Sex ratio at birth was defined as the proportion of male live births. RESULTS During the study period, there were 1 349 099 singleton live births (692 870 boys and 656 229 girls). The sex ratio at birth in the new cohort was 0.5134. In the new cohort, prenatal exposure to severe life events was not associated with a reduction in the sex ratio at birth [relative risk = 1.00 (95% confidence interval: 0.95-1.05)]. CONCLUSIONS In the new cohort, we did not find strong evidence that, in a stable western population, prenatal exposure to severe life events is associated with a reduction in the sex ratio at birth.

• Rates of preterm birth following antenatal maternal exposure to severe life events: a population-based cohort study.

  Authors: A S Khashan, R McNamee, K M Abel, P B Mortensen, L C Kenny, M G Pedersen, R T Webb, P N Baker

  Human reproduction (Oxford, England). 01/2009;

  BACKGROUND Preterm birth and other pregnancy complications have been linked to maternal stress during pregnancy. We investigated the association between maternal exposure to severe life events andBACKGROUND Preterm birth and other pregnancy complications have been linked to maternal stress during pregnancy. We investigated the association between maternal exposure to severe life events and risk of preterm birth. METHODS Mothers of all singleton live births (n = 1.35 million births) in Denmark between 1 January 1979 and 31 December 2002 were linked to data on their children, parents, siblings and partners. We defined exposure as death or serious illness in close relatives in the first or second trimesters or in the 6 months before conception. Log-linear binomial regression was used to estimate the effect of exposure on preterm birth, very preterm birth and extremely preterm birth. RESULTS There were 58 626 (4.34%) preterm births (<37 weeks), 11 732 (0.87%) very preterm births and 3288 (0.24%) extremely preterm births in the study cohort. Severe life events in close relatives in the 6 months before conception increased the risk of preterm birth by 16% (relative risk, RR = 1.16, [95% CI: 1.08-1.23]). Severe life events in older children in the 6 months before conception increased the risk of preterm birth by 23% (RR = 1.23, [95% CI: 1.02-1.49]) and the risk of very preterm birth by 59% (RR = 1.59, [95% CI: 1.08-2.35]). CONCLUSIONS Our population-based cohort study suggests that maternal exposure to severe life events, particularly in the 6 months before pregnancy, may increase the risk of preterm and very preterm birth.

• The validity and reliability of diagnoses of work-related mental ill-health.

  Authors: E O'Neill, R McNamee, R Agius, M Gittins, L Hussey, S Turner

  Occupational and environmental medicine. 11/2008; 65(11):726-31.

  OBJECTIVES: To establish the reliability and validity of work-related mental ill-health diagnoses. BACKGROUND: A UK-based surveillance scheme for work-related ill-health involving occupationalOBJECTIVES: To establish the reliability and validity of work-related mental ill-health diagnoses. BACKGROUND: A UK-based surveillance scheme for work-related ill-health involving occupational physicians (OPs) reporting suggests that mental ill-health incidence is increasing by around 13% per year, with anxiety, depression and "other work-related stress" being the most common diagnoses. There have been no studies of the validity and reliability of such diagnoses. Given the existence of a large network of psychiatrists (PSYs) also involved in surveillance of work-related ill-health, an opportunity arose to measure the concurrent validity and reliability of work-related mental ill-health diagnoses. METHODS: 100 anonymised summaries of cases previously reported by OPs or PSYs were collected; each was sent to 5 PSYs and 5 OPs, who assigned a diagnosis and judged whether the case was work-related. Concurrent validity of the ill-health aspect of the diagnoses, and of the opinion as to work-relatedness, was assessed by comparing the overall classifications of cases by OPs and PSYs. Reliability of the diagnostic classification was measured by kappa matrices. RESULTS: Diagnostic proportions for PSYs and OPs demonstrated good agreement for anxiety, depression, anxiety plus depression and "stress" (11%, 34%, 27%, 14%) and (14%, 30%, 27%, 17%), respectively. In both groups, kappa coefficients were high for a psychotic diagnosis (0.78, 95% CI: 0.74 to 0.83), but not as high for anxiety (0.27, 95% CI: 0.23 to 0.32), depression (0.34, 95% CI: 0.29 to 0.38) and "stress" (0.15, 95% CI: 0.10 to 0.19). The odds ratio of classifying a case as work-related among PSYs compared to OPs was 2.39 (95% CI: 1.68 to 3.38), p<0.001. CONCLUSIONS: The overall agreement between OPs and PSYs on mental ill-health diagnoses suggests that OP diagnoses are valid for epidemiological purposes. However, the within-group reliability of the diagnosis "stress" is low. Given differences in judgements about work-relatedness, further research is needed to investigate this aspect of a diagnosis.

• The effect of shift work on ischaemic heart disease.

  Authors: G Yadegarfar, R McNamee

  Occupational and environmental medicine. 08/2008; 65(8):575-6.

• Interacting effects of particulate pollution and cold temperature on cardiorespiratory mortality in Scotland.

  Authors: M Carder, R McNamee, I Beverland, R Elton, M van Tongeren, G R Cohen, J Boyd, W Macnee, R M Agius

  Occupational and environmental medicine. 04/2008; 65(3):197-204.

  OBJECTIVES: To determine whether the effect of black smoke on cardiorespiratory mortality is modified by cold temperatures. METHODS: Poisson regression models were used to investigate theOBJECTIVES: To determine whether the effect of black smoke on cardiorespiratory mortality is modified by cold temperatures. METHODS: Poisson regression models were used to investigate the relationship between lagged black smoke concentration and daily mortality, and whether the effect of black smoke on mortality was modified by cold temperature for three Scottish cities from January 1981 to December 2001. MAIN RESULTS: For all-cause respiratory and non-cardiorespiratory mortality, there was a significant association between mortality and lagged black smoke concentration. Generally the maximum black smoke effect occurred at lag 0, although these estimates were not statistically significant. A 10 mugm(-3) increase in the daily mean black smoke concentration on any given day was associated with a 1.68% (95% CI 0.72 to 2.65) increase in all-cause mortality and a 0.43% (95% CI -0.97 to 1.86), 5.36% (95% CI 2.93 to 7.84) and 2.13% (95% CI 0.82 to 3.47) increase in cardiovascular, respiratory and non-cardiorespiratory mortality, respectively, over the ensuing 30-day period. The effect of black smoke on mortality did not vary significantly between seasons (cool and warm periods). For all-cause, cardiovascular and non-cardiorespiratory mortality the inclusion of interaction terms did not improve the models, although for all-cause and non-cardiorespiratory mortality there was a suggestion for interaction between temperature and recent black smoke exposure. CONCLUSIONS: The results of this study suggested a greater effect of black smoke on mortality at low temperatures. Since extremes of cold and particulate pollution may coexist, for example during temperature inversion, these results may have important public health implications.

• Shift work, confounding and death from ischaemic heart disease.

  Authors: G Yadegarfar, R McNamee

  Occupational and environmental medicine. 04/2008; 65(3):158-63.

  OBJECTIVE: To investigate the relation between shift work and death from ischaemic heart disease (IHD) and evidence for confounding by social class and healthy shift worker effects. METHODS: AOBJECTIVE: To investigate the relation between shift work and death from ischaemic heart disease (IHD) and evidence for confounding by social class and healthy shift worker effects. METHODS: A case-referent study nested within an industrial cohort was used. Cases (n = 635) were cohort members who died of ischaemic heart disease (ICD 410-414) during 1950-98 aged 75 or under. Referents were matched on age and year of starting work at the site and were alive at time of case's death. Shift work status was determined from historical personnel records and pre-employment weight, height, blood pressure and smoking from medical records. Social class at first employment was inferred from job titles. To overcome potential bias due to a healthy shift worker hire effect, odds ratios were calculated from survivors 10 years after hire. To control for any healthy shift worker survivor effect, they were adjusted for duration of employment and time since termination of employment. Conditional logistic regression analysis was used to estimate ORs. RESULTS: 55% of subjects had worked as shift workers. Shift workers were more likely than day workers to belong to social class IV or V. The OR for shift workers compared with day workers, after adjustment for pre-employment risk factors, duration of employment and restricted to those who survived 10 years after hire was 1.11 (90% CI 0.90 to 1.37). This reduced to 1.04 (90% CI 0.83 to 1.30) after inclusion of social class. No dose-response relation was found. CONCLUSION: No excess risk of death from IHD for shift workers was found. The potential for confounding by social class in this relatively homogeneous cohort underlines the need to consider such confounding in more heterogeneous populations.

• The incidence of occupational skin disease as reported to The Health and Occupation Reporting (THOR) network between 2002 and 2005.

  Authors: S Turner, M Carder, M van Tongeren, R McNamee, S Lines, L Hussey, A Bolton, M H Beck, M Wilkinson, R Agius

  The British journal of dermatology. 11/2007; 157(4):713-22.

  BACKGROUND: Estimated incidence rates for occupational skin disease in the U.K. are provided by voluntary surveillance schemes involving dermatologists and occupational physicians. These rates allowBACKGROUND: Estimated incidence rates for occupational skin disease in the U.K. are provided by voluntary surveillance schemes involving dermatologists and occupational physicians. These rates allow monitoring of occupational dermatoses, and intervention planning aimed at reducing workplace risks. OBJECTIVES: To summarize occupational skin disease reported to The Health and Occupation Reporting (THOR) network (2002-2005), and to provide baseline information for comparison with future studies of occupational skin disease in the U.K. and beyond. METHODS: Incidence rates for occupational dermatoses were calculated using THOR data as numerators, and Labour Force Survey data or information from the most recent U.K. survey on provision of occupational physician services as denominators. RESULTS: In the U.K. (2002-2005) the average annual incidence rate of work-related skin disease reported to THOR by dermatologists was 91.3 [95% confidence interval (CI) 81.8-101.1] per million, and by occupational physicians was 316.6 (95% CI 251.8-381.3) per million. Most reports were of contact dermatitis: dermatologists 68.0 (95% CI 59.8-76.2) per million, occupational physicians 259.7 (95% CI 200.8-318.6) per million. CONCLUSIONS: Information produced by THOR is an important source for calculating incidence rates of occupational skin disease. A range of reporting groups should also be used when building an overall picture of occupational skin disease incidence in the U.K.

• Occupational noise exposure and ischaemic heart disease mortality.

  Authors: R McNamee, G Burgess, W M Dippnall, N Cherry

  Occupational and environmental medicine. 01/2007; 63(12):813-9.

  AIMS: To investigate the hypothesis that long term exposure to excessive noise can increase the risk of ischaemic heart disease. METHODS: A case-control design, nested within a cohort of nuclearAIMS: To investigate the hypothesis that long term exposure to excessive noise can increase the risk of ischaemic heart disease. METHODS: A case-control design, nested within a cohort of nuclear power workers employed at two sites in England over the period 1950-98, was used. Cases were men who died from ischaemic heart disease (ICD-9: 410-414) aged 75 or under; each was matched to a surviving control of the nearest age who joined the same site at the same time. Personal noise exposure was assessed retrospectively for each man by hygienists using (1) company work histories, (2) noise survey records from 1965-98, and (3) judgements about likely use of hearing protection devices. Men were classified into four groups according to their cumulative exposure to noise, with men whose exposure at the company never exceeded 85dB(A) for at least one year being considered "unexposed". Risks were compared via odds ratios (ORs) using conditional logistic regression and adjusted for systolic and diastolic blood pressure, height, BMI, and smoking, as measured at recruitment to the company. RESULTS: Analysis was based on 1101 case-control pairs. There was little difference between the exposure groups at recruitment. There was no evidence of increased risk at site A: the ORs for ischaemic heart disease mortality among low, medium, and high exposure categories, compared to unexposed men, being 1.04, 1.00, and 0.77. The corresponding ORs (95% CIs) at site B were 1.15 (0.81-1.65) 1.45 (1.02-2.06), and 1.37 (0.96-1.96). When the comparison was confined to men with at least five years of employment, these dropped to 1.07 (0.64-1.77), 1.33 (0.88-2.01), and 1.21 (0.82-1.79) respectively. CONCLUSIONS: The authors did not find statistically robust evidence of increased risk but the estimates at site B are consistent with those in a major cohort study. A strength of the present study is that the validity of noise estimation at site B has been demonstrated elsewhere.

• Predictive validity of a retrospective measure of noise exposure.

  Authors: R McNamee, G Burgess, W M Dippnall, N Cherry

  Occupational and environmental medicine. 01/2007; 63(12):808-12.

  AIMS: To investigate the validity of measures of noise exposure derived retrospectively for a cohort of nuclear energy workers for the period 1950-98, by investigating their ability to predictAIMS: To investigate the validity of measures of noise exposure derived retrospectively for a cohort of nuclear energy workers for the period 1950-98, by investigating their ability to predict hearing loss. METHODS: Subjects were men aged 45-65 chosen from a larger group of employees--assembled for a nested case-control study of noise and death from ischaemic heart disease--who had had at least one audiogram after at least five years' work. Average hearing loss, across both ears and the frequencies 0.5, 1, 2, and 4 kHz, was calculated from the last audiogram for each man. Previous noise exposure at work was assessed retrospectively by three hygienists using work histories, noise survey records from 1965-98, and judgement about use of hearing protection devices. Smoking and age at the time of the audiogram were extracted from records. Differences in hearing loss between men categorised by cumulative noise exposure were assessed after controlling for age, smoking, year of test, and previous test experience. RESULTS: There were 186 and 150 eligible subjects at sites A and B of the company respectively who were employed for an average of 20 years. Compared to men with less than one year's exposure to levels of 85dB(A) or greater, hearing loss was greater by 3.7 dB (90% CI -2.6 to 10.1), 3.8 dB (90% CI -2.6 to 10.3), 7.0 dB (90% CI 1.1 to 12.9) and 10.1 dB (90% CI 4.2 to 16.0) in the lowest to highest categories of cumulative noise exposure at site B. In contrast, at site A, the corresponding figures were -2.2 dB, -2.4 dB, -1.8 dB, and -4.4 dB, with no confidence interval excluding zero. CONCLUSIONS: Noise estimation at one site was shown to have predictive validity in terms of hearing loss, but not at the other site. Reasons for the differences between sites are discussed.

• The lagged effect of cold temperature and wind chill on cardiorespiratory mortality in Scotland.

  Authors: M Carder, R McNamee, I Beverland, R Elton, G R Cohen, J Boyd, R M Agius

  Occupational and environmental medicine. 11/2005; 62(10):702-10.

  AIMS: To investigate the lagged effects of cold temperature on cardiorespiratory mortality and to determine whether "wind chill" is a better predictor of these effects than "dry bulb" temperature.AIMS: To investigate the lagged effects of cold temperature on cardiorespiratory mortality and to determine whether "wind chill" is a better predictor of these effects than "dry bulb" temperature. METHODS: Generalised linear Poisson regression models were used to investigate the relation between mortality and "dry bulb" and "wind chill" temperatures in the three largest Scottish cities (Glasgow, Edinburgh, and Aberdeen) between January 1981 and December 2001. Effects of temperature on mortality (lags up to one month) were quantified. Analyses were conducted for the whole year and by season (cool and warm seasons). MAIN RESULTS: Temperature was a significant predictor of mortality with the strongest association observed between temperature and respiratory mortality. There was a non-linear association between mortality and temperature. Mortality increased as temperatures fell throughout the range, but the rate of increase was steeper at temperatures below 11 degrees C. The association between temperature and mortality persisted at lag periods beyond two weeks but the effect size generally decreased with increasing lag. For temperatures below 11 degrees C, a 1 degrees C drop in the daytime mean temperature on any one day was associated with an increase in mortality of 2.9% (95% CI 2.5 to 3.4), 3.4% (95% CI 2.6 to 4.1), 4.8% (95% CI 3.5 to 6.2) and 1.7% (95% CI 1.0 to 2.4) over the following month for all cause, cardiovascular, respiratory, and "other" cause mortality respectively. The effect of temperature on mortality was not observed to be significantly modified by season. There was little indication that "wind chill" temperature was a better predictor of mortality than "dry bulb" temperature. CONCLUSIONS: Exposure to cold temperature is an important public health problem in Scotland, particularly for those dying from respiratory disease.

• Optimal design and efficiency of two-phase case-control studies with error-prone and error-free exposure measures.

  Authors: R McNamee

  Biostatistics (Oxford, England). 11/2005; 6(4):590-603.

  This paper addresses optimal design and efficiency of two-phase (2P) case-control studies in which the first phase uses an error-prone exposure measure, Z, while the second phase measures true,This paper addresses optimal design and efficiency of two-phase (2P) case-control studies in which the first phase uses an error-prone exposure measure, Z, while the second phase measures true, dichotomous exposure, X, in a subset of subjects. Optimal design of a separate second phase, to be added to a preexisting study, is also investigated. Differential misclassification is assumed throughout. Results are also applicable to 2P cohort studies with error-prone and error-free measures of disease status but error-free exposure measures. While software based on the mean score method of Reilly and Pepe (1995, Biometrika 82, 299--314) can find optimal designs given pilot data, the lack of simple formulae makes it difficult to generalize about efficiency compared to one-phase (1P) studies based on X alone. Here, formulae for the optimal ratios of cases to controls and first- to second-phase sizes, and the optimal second-phase stratified sampling fractions, given a fixed budget, are given. The maximum efficiency of 2P designs compared to a 1P design is deduced and is shown to be bounded from above by a function of the sensitivities and specificities of Z. The efficiency of 'balanced' separate second-phase designs (Breslow and Cain, 1988, Biometrika 75, 11--20)-in which equal numbers of subjects are chosen from each first-phase strata-compared to optimal design is deduced, enabling situations where balanced designs are nearly optimal to be identified.

• Regression modelling and other methods to control confounding.

  Authors: R McNamee

  Occupational and environmental medicine. 08/2005; 62(7):500-6, 472.

• Physicians' beliefs in the assessment of work attribution when reporting musculoskeletal disorders.

  Authors: Y Chen, R Agius, R McNamee, S Turner, S Taylor, L Fulluck, S Lines, C Roberts, L Hussey

  Occupational medicine (Oxford, England). 07/2005; 55(4):298-307.

  BACKGROUND: There is considerable uncertainty about work-relatedness and musculoskeletal disorders in general, and it is also not clear how physicians decide whether work has caused a disorder in anBACKGROUND: There is considerable uncertainty about work-relatedness and musculoskeletal disorders in general, and it is also not clear how physicians decide whether work has caused a disorder in an individual patient. AIMS: To investigate physicians' beliefs about assessment of occupational attribution for work-related musculoskeletal disorders. METHODS: A questionnaire survey was sent to 526 occupational physicians and 248 rheumatologists on: characteristics of cases seen, assessment of work attribution, definition of work-relatedness and threshold for case reporting. Continuous variables were analysed by mean, standard deviation, an independent two-sample t-test and the Mann-Whitney test. Mean and median values were calculated and Spearman's rank test was applied to ranked data. RESULTS: Questionnaires were completed by 68% occupational physicians and 64% rheumatologists. Both groups of physicians believed that 'history of onset in relation to workplace changes' and 'symptoms consistent with work exposure' were the most important factors suggesting work attribution. They considered that the most important objective of a reporting scheme was detection of trends in disease incidence and that the most suitable criteria for defining work-relatedness was the probability that exposure at work 'more likely than not' caused the condition (mean 0.73; SD=0.17), in a perceived likelihood scale (0-1). CONCLUSION: There was a strong agreement between occupational physicians and rheumatologists on questions about work-relatedness and musculoskeletal disorders. The level of probability for concluding work-relatedness has been quantified.