Melanie Carder

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

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°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°C, a 1°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.

Measurement of trends in incidence of work-related skin and respiratory diseases, UK 1996-2005.

Objectives: The ability to measure temporal trends in disease incidence is important, but valid methods are needed. This study investigates UK trends during 1996–2005 in work-related skin and respiratory diseases including non-malignant pleural disease, asthma, mesothelioma and pneumoconiosis and the potential for bias when using surveillance systems for this purpose. Methods: The volunteer reporters in three surveillance schemes were specialist physicians for skin diseases, specialist physicians for respiratory diseases and occupational physicians, respectively, who provided monthly reports of new cases of disease which they considered work related. Poisson regression models were used to investigate variation by calendar year (trend), season and reporter characteristics. Separately, temporal patterns in the probabilities of non-response and zero reports were investigated. Annual changes in disease incidences were compared between reporter groups. Results: There was little evidence of change in incidences of non-malignant pleural disease, mesothelioma, skin neoplasia and urticaria, but falls were seen for contact dermatitis and pneumoconiosis. Although the directions of change were similar across reporter groups, the magnitude of annual change in incidence was often inconsistent: for occupational asthma, it was −1.9% (95% CI −5.2 to 1.4) and −12.1% (95% CI−19.5 to −4.1) using respiratory and occupational physician reports, respectively. Response rates were high (∼85%), but non-response increased slightly with membership time, as did the probability of a zero return in some groups. Adjustment of results for presumed reporting fatigue led to an upward correction in some calendar trends. Conclusions: As some estimated changes in incidence based on volunteer reporting may be biased by reporting fatigue, apparent downward trends need to be interpreted cautiously. Differences in the population bases of the surveillance schemes and UK health service capacity constraints may also explain the differences in trends found here.

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

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 allow monitoring of occupational dermatoses, and intervention planning aimed at reducing workplace risks.

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

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 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 μgm−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.

A comparison of short-term and long-term air pollution exposure associations with mortality in two cohorts in Scotland.

BACKGROUND Air pollution-mortality risk estimates are generally larger at longer-term, compared with short-term, exposure time scales. OBJECTIVE We compared associations between short-term exposure to black smoke (BS) and mortality with long-term exposure-mortality associations in cohort participants and with short-term exposure-mortality associations in the general population from which the cohorts were selected. METHODS We assessed short-to-medium-term exposure-mortality associations in the Renfrew-Paisley and Collaborative cohorts (using nested case-control data sets), and compared them with long-term exposure-mortality associations (using a multilevel spatiotemporal exposure model and survival analyses) and short-to-medium-term exposure-mortality associations in the general population (using time-series analyses). RESULTS For the Renfrew-Paisley cohort (15,331 participants), BS exposure-mortality associations were observed in nested case-control analyses that accounted for spatial variations in pollution exposure and individual-level risk factors. These cohort-based associations were consistently greater than associations estimated in time-series analyses using a single monitoring site to represent general population exposure {e.g., 1.8% [95% confidence interval (CI): 0.1, 3.4%] vs. 0.2% (95% CI: 0.0, 0.4%) increases in mortality associated with 10-μg/m³ increases in 3-day lag BS, respectively}. Exposure-mortality associations were of larger magnitude for longer exposure periods [e.g., 3.4% (95% CI: -0.7, 7.7%) and 0.9% (95% CI: 0.3, 1.5%) increases in all-cause mortality associated with 10-μg/m³ increases in 31-day BS in case-control and time-series analyses, respectively; and 10% (95% CI: 4, 17%) increase in all-cause mortality associated with a 10-μg/m³ increase in geometic mean BS for 1970-1979, in survival analysis]. CONCLUSIONS After adjusting for individual-level exposure and potential confounders, short-term exposure-mortality associations in cohort participants were of greater magnitude than in comparable general population time-series study analyses. However, short-term exposure-mortality associations were substantially lower than equivalent long-term associations, which is consistent with the possibility of larger, more persistent cumulative effects from long-term exposures.

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

Objective 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. Method 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. Results 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. Conclusion 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

BACKGROUND Construction workers are at increased risk of work-related ill-health (WRI) worldwide. AIMS To compare the incidence of medically reported WRI in occupations within the UK construction industry according to job title. METHODS 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. RESULTS 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). CONCLUSIONS 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.

Evaluating interventions aimed at reducing occupational exposure to latex and rubber glove allergens

Objective Concerns over occupational exposures to blood-borne viruses resulted in increased protective glove use; consequentially latex allergy became a hazard for some occupational groups. Interventions aimed at managing this problem included substitution measures (eg, non-powdered/non-latex gloves), but such changes may not occur simultaneously across occupational sectors. This study evaluated whether the incidence of occupational dermatoses fell after interventions aiming to reduce exposure to ‘latex and rubber glove allergens’ (‘latex’) were introduced, and whether these interventions were more effective for healthcare workers (HCWs), compared with non-HCWs. Methods Incidence rate ratios (IRRs) comparing cases reported to EPIDERM (a UK-wide surveillance scheme) during post versus pre-intervention periods were calculated, both where ‘latex’ was cited and for cases associated with other exposures (‘controls’). Results Among HCWs, cases of contact urticaria and allergic contact dermatitis (ACD) where ‘latex’ was cited showed significant downward trends post-intervention, with IRRs of 0.72, 95% CI; 0.52 to 1.00 and 0.47, 95% CI; 0.35 to 0.64 respectively. For HCWs, this fall in ‘latex’ associated ACD was significantly greater (p=0.02) than for other exposures (‘controls’) IRR=0.85, 95% CI; 0.57 to 1.28, and greater than that among non-HCWs (IRR 0.75, 95% CI; 0.61 to 0.93). Increases over time were seen for irritant contact dermatitis (ICD) reporting for HCWs, both for cases associated with ‘latex’ (IRR 1.47, 95% CI: 1.02 to 2.13) and for other exposures (‘controls’) IRR 1.36, 95% CI 1.06 to 1.76, but not for non-HCWs. Conclusions A reduction in overall ACD, particularly in HCWs, coincided with interventions aimed at managing workplace contact dermatoses associated with ‘latex’ exposure. A coincidental rise in ICD reporting is also important, both for hand care and for infection control strategies.

Time trends in the incidence of work-related mental ill-health and musculoskeletal disorders in the UK.

Objectives To determine UK trends (from 1996 to 2009) in incidence of work-related mental ill-health and musculoskeletal disorders, for all industry as well as for health and social care employees. Second, to investigate whether there may have been a recent shift from a physical to psychological perspective in how patients present their illness by comparing reporting trends for back pain and ‘other work stress’. Methods Multilevel models were used to investigate changes in incidence of work-related illness, as diagnosed by specialist physicians. The dependent variable comprised case reports to The Health and Occupation Research network. Comparisons were made between medical specialties, industry (health and social care vs all other employees), gender and diagnosis. Results Trends for Occupational Physicians’ (OP) reporting mental ill-health (average annual increase +3.7% (95% CI +2.2% to +5.2%)) differed significantly (p<0.001) from psychiatrists’ reporting over the same time period (−5.9% (95% CI −7.6% to −4.2%)). For OPs’ reporting, the rate of increase was greater for females and for health and social care employees. A fall in incidence of musculoskeletal disorders for OPs of −5.8% (95% CI −7.3% to −4.3%) and rheumatologists’ reporting −6.6% (95% CI −8.3% to −4.8%) was found, with little variation by gender or industry. Within health and social care, an increase in incidence of ‘other work stress’ was accompanied by a similar decrease in ‘spine/back pain’. Conclusions The evidence presented is consistent with a shift in the presentation of ill-health from a physical to psychological perspective, although changes in hazards, prevention measures and physician awareness should also be considered as explanations.

Assessing the impact of national level interventions on workplace respiratory disease in the UK: part 1—changes in workplace exposure legislation and market forces

Objective The 2004 amendment to the Control of Substances Hazardous to Health 2002 regulations (COSHH 2004) introducing workplace exposure limits (WELs) was enacted in the UK in 2005. This study aimed to determine whether introducing this legislation coincided with a reduction in the incidence of work-related short latency respiratory disease (SLRD) attributed to the agents with a WEL. The second objective was to determine whether changes in legislation, WELs and market forces coincided with a reduction in the incidence of SLRD attributed to glutaraldehyde and latex. Method Reports of SLRD made to the Surveillance of Work-related and Occupational Respiratory Disease scheme were used to estimate the change in incidence within reporters between two time periods (interrupted time series design) using a longitudinal, negative binomial regression model with β distributed random effects. A statistical interaction term was included in the model to make comparisons between the groups defined by suspected causal agent and/or occupation, essentially comparing two interrupted time series. Time periods were defined prospectively representing the changes in legislation or market forces. Results The introduction of the COSHH 2004 legislation in the UK coincided with a significant reduction in reports of SLRD attributed to agents with a WEL relative to those without a WEL (ratio of incidence rate ratios: 0.70; 95% CI 0.52 to 0.93) and a significant reduction in SLRD attributed to glutaraldehyde in healthcare workers (0.20; 0.07 to 0.57) and latex in all workers (0.37; 0.16 to 0.85). Conclusions These data are consistent with a beneficial effect of legislation aiming to reduce workplace exposures.