Post-acute COVID-19 complications in UK doctors: results of a cross-sectional survey.

BACKGROUND: As a consequence of their occupation, doctors and other healthcare workers were at higher risk of contracting coronavirus disease 2019 (COVID-19), and more likely to experience severe disease compared to the general population. However, systematic information on post-acute COVID complications in doctors is very limited. AIMS: This study aimed to determine the symptoms, perceived determinants, health and occupational impact, and consequent needs relating to post-acute COVID complications in UK doctors. METHODS: An online cross-sectional survey was distributed to UK doctors self-identifying as having Long COVID or other post-acute COVID complications. RESULTS: Of 795 responses, 603 fulfilled the inclusion criteria of being a UK-based medical doctor experiencing one or more post-acute COVID complications. Twenty-eight per cent reported a lack of adequate Respiratory Protective Equipment at the time of contracting COVID-19. Eighteen per cent of eligible respondents reported that they had been unable to return to work since acquiring COVID. CONCLUSIONS: Post-acute COVID (Long COVID) in UK doctors is a substantial burden for respondents to our questionnaire. The results indicated that insufficient respiratory protection could have contributed to occupational disease, with COVID-19 being contracted in the workplace, and resultant post-COVID complications. Although it may be too late to address the perceived determinants of inadequate protection for those already suffering with Long COVID, more investment is needed in rehabilitation and support of those afflicted.

Covid-19: statutory means of scrutinizing workers' deaths and disease.

BACKGROUND: By law, covid-19 disease and deaths in workers may lead to coroners' inquests and/or Health and Safety Executive (HSE) investigations. AIMS: This study assesses the adequacy of these statutory means to yield recommendations for prevention of acquiring covid-19 infection from work. METHODS: Covid-19 guidance from the chief coroner and the HSE was appraised, including using Office for National Statistics (ONS) data. Practitioners were asked to estimate the likelihood that covid-19 disease may have arisen from 'near-miss' scenarios. Data from the judiciary and the HSE were analysed. RESULTS: The coroners' guidance allowed a wider range of reports of death than did the HSE and conformed better with ONS data on covid-19 mortality by occupation. In the practitioner survey, 62 respondents considered a higher likelihood that reported covid-19 cases would have arisen from the scenario deemed unreportable as a 'dangerous occurrence' by HSE than the reportable scenario (P < 0.001). On average there was only one coroner's report to prevent future death from occupational disease every year in England and Wales. The HSE dealt with a yearly average of 1611 reports of work-related disease including 104 on biological agents, but has received about 9000 covid-19 reports. CONCLUSIONS: Current HSE guidance for reporting work-related covid-19 may miss many thousands of cases and needs further iteration. Coroners have very limited experience of inquiry into occupational disease caused by biological agents compared with the HSE. Concerns regarding national policy such as on protective equipment warrant a full public inquiry.

Sentinel approach to detect emerging causes of work-related respiratory diseases.

BACKGROUND: The world of work is continually changing, and this could result in new and emerging risks being introduced, including those that may cause work-related respiratory diseases (WRRD). AIMS: To describe recently emerging and new cases of WRRD and the relevant methodology using data in a national occupational respiratory disease surveillance scheme in the UK. METHODS: Incident cases of respiratory diseases reported by physicians to the Surveillance of Work-related and Occupational Respiratory Disease (SWORD) between January 2015 and December 2017 were included. Potentially emerging respiratory hazards manifesting in SWORD data were identified with the following hierarchical approach: (i) new respiratory disease not previously associated with work, (ii) specific exposure/agent not previously associated with WRRD and (iii) industry and/or occupation not previously associated with WRRD. RESULTS: A total of 1215 cases of WRRD were reported to SWORD between January 2015 and December 2017. No new WRRD were identified. Thirteen potentially emerging causes of occupational asthma were identified, including exposures to agents such as ninhydrin. Four potential new causes were identified for interstitial pneumonia, which included wood and brass dust. Two potentially emerging causes of WRRD were identified for inhalational accidents (green coffee and nitrocellulose), hypersensitivity pneumonitis (diphenylmethane diisocyanate and salami mould), rhinitis (morphine and Amaranthus quitensis) and sarcoidosis (prions and horses). CONCLUSIONS: Continuous monitoring and reporting of any new work-related disease is a critical function of any occupational disease reporting scheme. Potential emerging causes of work-related health risks have been identified by using a simple and systematic way of detecting emerging causes of WRRDs.

[The French "pill scare": Did women go to a gynecologist more often to have an easier access to the IUD?] / La « crise des pilules ¼ en France : les femmes ont-elles davantage consulté un.e gynécologue afin d'accéder plus facilement au DIU ?

BACKGROUND: In December 2012, a media controversy about negative side-effects of oral contraceptives on women's health, also called "pill scare", broke out in France. While several analyses highlighted a change in women's contraceptive practices following this media controversy, no analysis has been conducted to determine the possible changes in their choices of health professionals and its repercussions on their contraceptive use. METHODS: Our study is based on data from three population-based cross-sectional surveys conducted in 2010, 2013 and 2016 (Fecond 2010, Fecond 2013 and Baromètre Santé 2016) that collected information on women's contraceptive practices and the specialties of the health professionals having prescribed the methods they were using. RESULTS: Between 2010 and 2016, women went to a gynecologist or a midwife more often than to a general practitioner for prescription of a reversible contraceptive method. However, their changes in visiting prescribers did not explain the changes in their contraceptive practices observed over the period. In 2016, access to health professional remained largely dependent on women's socio-demographic characteristics: older ones and those from a more privileged social background or living in urban areas were more likely to consult a gynecologist for prescription of their contraceptive method. On the other hand, consultations of midwives for contraceptive prescription were more frequent among women with children and among those who relied on public health insurance alone. CONCLUSION: Following the "pill scare" that occurred in France in December 2012, the decision by some women to use the IUD instead of the pill led them to change health professionals, and also led practitioners to change their prescribing practices.

The preventable burden of work-related ill-health.

Background: The fraction of ill-health overall attributable to occupational conditions has not been extensively evaluated, thus contributing to the perception of a lesser relevance of education and research in occupational health in respect to other fields of medical research and practice. Aims: To assess the relevance of work-related conditions on the aetiology of human ill-health in different health domains. Methods: We extracted the risk estimates associated with heritability and with occupational risk factors for chronic lymphocytic leukaemia (CLL), major depressive disorder (MDD) and long QT syndrome (LQTS) from 13 published international reports. The selection criteria for the eligible studies were: genome-wide studies, or studies of the occupational risk factors associated with one of the three diseases of interest. We calculated and compared the respective population attributable fraction for the combined occupational risk factors, and for heritability. Results: We estimated that occupational risk factors would account for 12% (95% confidence interval (CI) 4-19) of CLL, 11% (95% CI 7-15) of MDD and 10% (95% CI 2-13) of LQTS burden in the general population. The corresponding figures for heritability would be 16% (95% CI 11-22), 28% (95% CI 20-5) and 17% (95% CI 7-27). Conclusions: More efforts in capacity building and research in occupational health are warranted aiming to prevent ill-health and to preserve a productive life for the ageing work population.

Work-related ill-health in radiographers.

BACKGROUND: In the UK in 2015/16, 1.3 million workers self-reported a work-related illness (WRI) of which an estimated 41% were due to musculoskeletal disorders (incidence rate 550 cases per 100000 people) and 37% were related to stress, anxiety and depression. Little is known about the incidence of WRIs in radiographers. AIMS: To analyse the medically reported incidence of WRIs among radiographers in the UK between 1989 and 2015. METHODS: Incident cases reported by physicians to The Health and Occupation Research (THOR) network through its specialist schemes from 1989 to 2015 were analysed, using the Labour Force Survey as denominator where appropriate. RESULTS: In total, 218 cases (966 estimated cases) were reported. Of these 190 were in women. The mean age was 40.2 (20-91 years) SD ± 11.8 years. Most cases were reported to the Occupational Physicians Reporting Activity (OPRA) scheme (n = 92). A skin diagnosis was the most frequently reported (n = 77), followed by musculoskeletal (n = 60). Within the EPIDERM scheme, radiographers had the highest incidence rate when compared to all other occupations. CONCLUSIONS: Radiographers had a higher incidence of WRI compared to all other occupations. The most frequently reported WRI was skin conditions. The observed increase in incidence is likely to be due to the increase in the number of radiographers over that time period, although there was no evidence that WRI within radiographers are declining.

Epidemiology of occupational hypersensitivity pneumonitis; reports from the SWORD scheme in the UK from 1996 to 2015.

OBJECTIVE: To estimate the reported incidence of occupational hypersensitivity pneumonitis (OHP) in the UK and to consider whether the pattern of attributed causation has changed over time. METHODS: All cases of OHP reported to the SWORD scheme between January 1996 and December 2015 were classified into 1 of 10 categories of the suspected agent. Cases were grouped into four 5-year time periods to examine any changing pattern in incidence or suspected causation. For each time period, the annual incidence was calculated using the estimated number of reported cases and the working population of the UK. RESULTS: Between 1996 and 2015, there were 202 actual cases of OHP reported to SWORD, equating to an estimated 818 cases, when adjusting for the sampling ratio. Over this period, the annual UK incidence was 1.4 per million workers. The mean (SD) age of reported cases was 52 (13) years, and cases were four-times more likely to be men than women. Over the study period, there was a fall in the proportion of cases reported to be due to agricultural exposures (44-12%), and an increase in cases due to metalworking fluids (MWFs, 2-45%). CONCLUSIONS: Over the last 20 years, the incidence of OHP in the UK has been ∼1-2 cases per million workers per year. Working with water-based MWFs is now the most commonly suspected causative exposure for OHP cases reported to the SWORD scheme in the UK.

Differential reporting of work-related mental ill-health in doctors.

BACKGROUND: Evidence suggests that the medical profession is reluctant to report mental ill-health despite its high prevalence. AIMS: To compare differential reporting patterns in the incidence of work-related mental ill-health (WRMIH) affecting doctors with selected comparison occupational groups, as determined by surveillance by general practitioners (GPs), specialist psychiatrists and occupational physicians (OPs). METHODS: New cases of medically reported WRMIH were reported prospectively between 2006 and 2009 by GPs, psychiatrists and OPs as part of The Health and Occupation Research (THOR) network. For GP and psychiatry reporting schemes, incidence rates (IRs) for doctors, nurses, teachers, corporate managers and protective service workers were calculated using information from the Labour Force Survey as the denominator. In OP surveys, participating reporters provided denominator information to calculate IRs for doctors, nurses and teachers. RESULTS: Average annual IRs expressed per 100000 person/years employed as reported by GPs, psychiatrists and OPs, respectively, were: doctors (309, 971, 430), nurses (891, 208, 670), teachers (1040, 136, 210) and for GPs and psychiatrists, respectively, were: protective service workers (1432, 721) and corporate managers (428, 90). Psychiatrists reported a higher incidence of WRMIH in doctors, whereas GPs reported higher incidences of WRMIH in other occupations (chi-squared test, P < 0.001). CONCLUSIONS: The distribution of the incidence of new cases reported across different schemes suggests a differential reporting pattern of WRMIH in doctors. The higher IR for doctors in psychiatrist-reported WRMIH could be due to factors such as disease severity and bypassing formal referral channels.

Occupational asthma caused by an epoxy amine hardener.

We describe a 43-year-old epoxy floor layer who developed work-related asthma while exposed to an epoxy hardener based on isophorone diamine (IPDA). Challenge exposures to the curing of the epoxy resin system and subsequently to the polyfunctional amine hardener containing IPDA both elicited delayed asthmatic reactions. This report further indicates that exposure to epoxy hardeners containing polyfunctional amines should be considered as a potential cause of occupational asthma. Appropriate work hygiene measures should be implemented to minimize airborne exposure to these volatile compounds.

EELAB: an innovative educational resource in occupational medicine.

BACKGROUND: Postgraduate education, training and clinical governance in occupational medicine (OM) require easily accessible yet rigorous, research and evidence-based tools based on actual clinical practice. AIMS: To develop and evaluate an online resource helping physicians develop their OM skills using their own cases of work-related ill-health (WRIH). METHODS: WRIH data reported by general practitioners (GPs) to The Health and Occupation Research (THOR) network were used to identify common OM clinical problems, their reported causes and management. Searches were undertaken for corresponding evidence-based and audit guidelines. A web portal entitled Electronic, Experiential, Learning, Audit and Benchmarking (EELAB) was designed to enable access to interactive resources preferably by entering data about actual cases. EELAB offered disease-specific online learning and self-assessment, self-audit of clinical management against external standards and benchmarking against their peers' practices as recorded in the research database. The resource was made available to 250 GPs and 224 occupational physicians in UK as well as postgraduate OM students for evaluation. RESULTS: Feedback was generally very favourable with physicians reporting their EELAB use for case-based assignments. Comments such as those suggesting a wider range of clinical conditions have guided further improvement. External peer-reviewed evaluation resulted in accreditation by the Royal College of GPs and by the Faculties of OM (FOM) of London and of Ireland. CONCLUSIONS: This innovative resource has been shown to achieve education, self-audit and benchmarking objectives, based on the participants' clinical practice and an extensive research database.

Reporting and prediction of work-related sickness absence by general practitioners.

BACKGROUND: Information on sickness absence (SA) duration in general practice is difficult to record. The duration of absence certified by general practitioners (GPs) can be viewed as a prognosis for return to work. The Health and Occupation Research network in General Practice (THOR-GP) collects SA information from GPs associated with cases of work-related ill-health. A sample of these cases is followed up 1 year retrospectively to gather information on the duration of absence. AIMS: To examine the extent of the underestimation of SA in routinely reported data and to investigate how well GPs predict patients' return to work. METHODS: THOR-GPs submit case and SA information using a web-based form. GPs who submitted selected cases were asked about the total number of days of SA and whether the patient had returned to work. RESULTS: THOR-GPs' routine SA data collection underestimated absence duration by 61%. According to the retrospective data, a much larger proportion of periods of absence due to work-related mental ill-health developed into long-term SA (60%) than episodes attributed to musculoskeletal disorders (32%). In over half the reported cases, the return to work was longer than the GP initially predicted. CONCLUSIONS: THOR-GP prospectively reported SA data underestimated the total length of absence; however, these data can examine the episodic rates of absence within different groups. More accurate longitudinal data can be collected retrospectively. GPs' ability to predict the length of time a patient will be away from work is important to enable treatment and rehabilitation planning in order to decrease the likelihood of a patient falling into long-term SA.

The impact of national-level interventions to improve hygiene on the incidence of irritant contact dermatitis in healthcare workers: changes in incidence from 1996 to 2012 and interrupted times series analysis.

BACKGROUND: Reducing healthcare-associated infections (HCAI) has been a priority in the U.K. over recent decades and this has been reflected in interventions focusing on improving hygiene procedures. OBJECTIVES: To evaluate whether these interventions coincided with an increased incidence of work-related irritant contact dermatitis (ICD) attributed to hand hygiene or/and other hygiene measures in healthcare workers (HCWs). METHODS: A quasi-experimental (interrupted time series) design was used to compare trends in incidence of ICD in HCWs attributed to hygiene before and after interventions to reduce HCAI with trends in the same periods in control groups (ICD in other workers). Cases of ICD reported to a U.K. surveillance scheme from 1996 to 2012 were analysed. The time periods compared were defined objectively based on the dates of the publication of national evidence-based guidelines, the U.K. Health Act 2006 and the Cleanyourhands campaign. RESULTS: The reported incidence of ICD in HCWs attributed to hygiene has increased steadily from 1996 to 2012 [annual incidence rate ratio (95% confidence interval): hand hygiene only 1.10 (1.07-1.12); all hygiene 1.05 (1.03-1.07)], whereas the incidence in other workers is declining. An increase in incidence of ICD in HCWs attributed to hand hygiene was observed at the beginning of the Cleanyourhands campaign. CONCLUSIONS: The increasing incidence of ICD in HCWs combined with the popularity of interventions to reduce HCAI warrants increased efforts towards identifying products and implementing practices posing the least risk of ICD.

The utility of information collected by occupational disease surveillance systems.

BACKGROUND: The Health and Occupation Research (THOR) network in the UK and the Republic of Ireland (ROI) is an integrated system of surveillance schemes collecting work-related ill-health (WRIH) data since 1989. In addition to providing information about disease incidence, trends in incidence and the identification of new hazards, THOR also operates an ad hoc data enquiry service enabling interested parties to request information about cases of WRIH reported to THOR. AIMS: To examine requests for information made to a network of surveillance schemes for WRIH in the UK. METHODS: Analysis via SPSS of data requests received by THOR between 2002 and 2014. RESULTS: A total of 631 requests were received by THOR between 2002 and 2014. Requests were predominantly submitted by participating THOR physicians (34%) and the main THOR funder-the UK Health & Safety Executive (HSE) (31%). The majority (67%) of requests were for information about work-related respiratory or skin disease with relatively few requests for other diagnoses, such as musculoskeletal or mental ill-health. Requests frequently related to a specific industry and/or occupation (42%) and/or a specific causal agent (58%). CONCLUSIONS: Data collected by occupational disease surveillance systems such as THOR are an extremely useful source of information, the use of which extends beyond informing government on disease incidence and trends in incidence. The data collected provide a framework that can assist a wide range of enquirers with clinical diagnoses, identification of suspected causative agents/exposures and to highlight growing risks in particular industrial and occupational sectors.

Chemical determinants of occupational hypersensitivity pneumonitis.

BACKGROUND: Workplace inhalational exposures to low molecular weight (LMW) chemicals cause hypersensitivity pneumonitis (HP) as well as the more common manifestation of respiratory hypersensitivity, occupational asthma (OA). AIMS: To explore whether chemical causation of HP is associated with different structural and physico-chemical determinants from OA. METHODS: Chemical causes of human cases of HP and OA were identified from searches of peer-reviewed literature up to the end of 2011. Each chemical was categorized according to whether or not it had been the attributed cause of at least one case of HP. The predicted asthma hazard was determined for each chemical using a previously developed quantitative structure-activity relationship (QSAR) model. The chemicals in both sets were independently and 'blindly' analysed by an expert in mech anistic chemistry for a qualitative prediction of protein cross-linking potential and determination of lipophilicity (log K ow). RESULTS: Ten HP-causing chemicals were identified and had a higher median QSAR predicted asthma hazard than the control group of 101 OA-causing chemicals (P < 0.01). Nine of 10 HP-causing chemicals were predicted to be protein cross-linkers compared with 24/92 controls (P < 0.001). The distributions of log K ow indicated higher values for the HP list (median 3.47) compared with controls (median 0.81) (P < 0.05). CONCLUSIONS: These findings suggest that chemicals capable of causing HP tend to have higher predicted asthma hazard, are more lipophilic and are more likely to be protein cross-linkers than those causing OA.

Attribution of mental illness to work: a Delphi study.

BACKGROUND: Clinicians may be asked whether mental ill-health has been caused by work but there is no guidance on how this judgement should be made. AIMS: To seek a consensus on the factors that should be considered and how they should be sought when attributing mental ill-health to work. METHODS: A three-round Delphi study involving expert academics, occupational physicians, psychiatrists and psychologists. We deemed consensus had been reached when 66% or more of the experts were in agreement. RESULTS: Of 54 invited experts, 35 (65%) took part in the first round, 30 of these 35 (86%) in the second and 29 of these 30 (97%) in the final round. Consensus was reached for 11 workplace stressors: high job strain; effort-reward imbalance; major trauma; interpersonal conflict; inadequate support; role ambiguity; person-job mismatch; organizational injustice; organizational culture; work scheduling and threats to job security. Seven personal factors were identified as being important: previous mental illness; personality traits of neuroticism; adverse life events or social circumstances; resilience; a family history of mental illness and secondary gain. The worker, manager and co-workers were thought to be the most useful sources of workplace information. Consensus was reached for a definition of occupational mental illness but not for a threshold of work-relatedness. CONCLUSIONS: The attribution of mental ill-health to work is complex and involves the consideration of both workplace stressors and personal factors of vulnerability. Clinical consultation with an occupational physician who is familiar with the workplace is central to the process.

Workplace injury data reported by occupational physicians and general practitioners.

BACKGROUND: Accurate workplace injury data are useful in the prioritization of prevention strategies. In the UK, physicians report workplace ill-health data within The Health and Occupation Research (THOR) network, including injury case reports. AIMS: To compare workplace injury data reported by occupational physicians (OPs) and general practitioners (GPs) to THOR. METHODS: Injury cases reported by OPs and GPs, reported to THOR between 2006 and 2012 were analysed. Demographics, industrial groups, nature of injury, kind of accident and site of injury were compared. Data on sickness absence for workplace injuries reported by GPs were investigated. RESULTS: In total, 2017 workplace injury cases were reported by OPs and GPs. Males were more likely to sustain a workplace accident than females. Sprains and strains were reported most often, with the upper limbs being affected most frequently. Slips, trips and falls were identified as important causal factors by both OPs and GPs. Psychological injuries also featured in THOR reporting, with a higher proportion reported by OPs (21%) than by GPs (3%). The proportion of people classified as 'unfit' by GPs reduced following the introduction of the 'fit' note. CONCLUSIONS: THOR reports returned by OPs and GPs provide a valuable source of information of workplace injury data, and complement other sources of information, such as the Reporting of Injuries, Diseases and Dangerous Occurrences Regulations and the Labour Force Survey.

Isocyanate exposure and asthma in the UK vehicle repair industry.

BACKGROUND: Organic diisocyanates are a common cause of occupational asthma, particularly in motor vehicle repair (MVR) workers. The UK Health & Safety Laboratory provides screening for urinary hexamethylenediamine (UHDA), a biomarker of exposure to 1,6-hexamethylene diisocyanate (HDI). The UK Surveillance of Work-related and Occupational Respiratory Disease scheme (SWORD) has collected reports of occupational asthma since 1996. AIMS: To compare trends in HDI exposure with trends in the incidence of work-related asthma attributed to isocyanates or paint spraying in MVR workers reported to SWORD. METHODS: Two-level regression models were used to estimate trends in UHDA levels and work-related asthma in MVR workers reported to SWORD. The direction and magnitude of the trends were compared descriptively. RESULTS: From 2006 to 2014, there was a significant decline in the number of urine samples with detectable levels of UHDA (odds ratio = 0.96; 95% confidence intervals 0.94-0.98) and minimal change in those over the guidance value (1.03; 1.00-1.06). Over the same period, there was a significant decline in all asthma cases attributed to isocyanates or paint spraying reported to SWORD (0.90; 0.86-0.94) and a non-significant decline among MVR workers (0.94; 0.86-1.02). CONCLUSIONS: The simultaneous decrease in HDI exposure and incident cases of asthma reported to SWORD is temporally consistent with a reduction in exposure to airborne isocyanate leading to a reduction in asthma. Although this is not direct evidence of a causal relationship between the two trends, it is suggestive.

Has the fit note reduced general practice sickness certification rates?

BACKGROUND: In 2010, the fit note replaced the sick note to help focus on what people are capable of doing, rather than signing patients 'off sick'. AIMS: To compare proportions of work-related ill-health issued with sickness certification pre- and post-fit note introduction and assess sickness absence trends. METHODS: General practitioners (GPs) report data on work-related ill-health and sickness absence via The Health and Occupation Research network in General Practice. The proportion of cases issued with sickness certification 4 years before and 3 years after the fit note introduction were compared. Changes in certification incidence rate ratios were measured over time. RESULTS: Participating GPs reported 5517 cases of work-related ill-health. Pre-fit note introduction 50% of cases were certified sick. There was no change in the proportion of cases certified sick in the first year post-fit note, despite 13% of cases classified as 'maybe fit'. However, in the second year, the proportion of cases certified sick had reduced significantly (41%) and a larger proportion (19%) was advised on workplace adjustments. In the third year post-introduction, there was a slight rise in the proportion of cases certified sick; therefore, although there was a fall of 2% per annum in certification rates, this was not significant. CONCLUSIONS: In the first year post-fit note introduction, modifications to work were recommended for people who would previously have been declared fit. Trends analyses showed a slight decrease in the certification rate, possibly indicating GPs will become more practised in advising on workplace adjustments.

Investigating work-related neoplasia associated with solar radiation.

BACKGROUND: Both solar and non-solar exposures associated with occupation and work tasks have been reported as skin carcinogens. In the UK, there are well-established surveillance schemes providing relevant information, including when exposures took place, occupation, location of work and dates of symptom onset and diagnosis. AIMS: To add to the evidence on work-related skin neoplasia, including causal agents, geographical exposure and time lag between exposure and diagnosis. METHODS: This study investigated incident case reports of occupational skin disease originating from clinical specialists in dermatology reporting to a UK-wide surveillance scheme (EPIDERM) by analysing case reports of skin neoplasia from 1996 to 2012 in terms of diagnosis, employment, suspected causal agent and symptom onset. RESULTS: The suspected causal agent was 'sun/sunlight/ultraviolet light' in 99% of the reported work-related skin neoplasia cases. Most cases reported (91%) were in males, and the majority (62%) were aged over 65 at the time of reporting. More detailed information on exposure was available for 42% of the cases, with the median time from exposure to symptom onset ranging from 44 (melanoma) to 57 (squamous cell carcinoma) years. Irrespective of diagnostic category, the median duration of exposure to 'sun/sunlight/ultraviolet light' appeared longer where exposures occurred in the UK (range 39-51 years) rather than outside the UK (range 2.5-6.5 years). CONCLUSIONS: It is important to provide effective information about skin protection to workers exposed to solar radiation, especially to outdoor workers based outside the UK.

A refined QSAR model for prediction of chemical asthma hazard.

BACKGROUND: A previously developed quantitative structure-activity relationship (QSAR) model has been extern ally validated as a good predictor of chemical asthma hazard (sensitivity: 79-86%, specificity: 93-99%). AIMS: To develop and validate a second version of this model. METHODS: Learning dataset asthmagenic chemicals with molecular weight (MW) <1 kDa were identified from reports published in the peer-reviewed literature before the end of 2012. Control chemicals for which no reported case(s) of occupational asthma had been identified were selected at random from UK and US occupational exposure limit tables. MW banding was used in an attempt to categorically match the control group for MW distribution of the asthmagens. About 10% of chemicals in each MW category were excluded for use as an external validation set. An independent researcher utilized a logistic regression approach to compare the molecular descriptors present in asthmagens and controls. The resulting equation generated a hazard index (HI), with a value between zero and one, as an estimate of the probability that the chemical had asthmagenic potential. The HI was determined for each compound in the external validation set. RESULTS: The model development sets comprised 99 chemical asthmagens and 204 controls. The external validation showed that using a cut-point HI of 0.39, 9/10 asthmagenic (sensitivity: 90%) and 23/24 non-asthmagenic (specificity: 96%) compounds were correctly predicted. The new QSAR model showed a better receiver operating characteristic plot than the original. CONCLUSIONS: QSAR refinement by iteration has resulted in an improved model for the prediction of chemical asthma hazard.