Investigating and analysing workplace clusters of diseases: a Health & Safety Executive perspective.

BACKGROUND: Clusters of disease arising in workplaces cause concern among the management of the company, the workers affected and their families and friends. Chance is the most likely explanation for their occurrence, although a number of real workplace hazards have been identified through their observation and investigation. Employers have a duty to investigate such occurrences in order to assess whether some unknown or unidentified hazard is at work and to take the appropriate action. Several papers have been published over the last 15 years or so that set out a method for investigating workplace clusters of disease. Aims This paper presents the steps in the approach taken by the Health & Safety Executive in Great Britain. METHOD: An initial step identifies the relevant stakeholders at the outset, in order to maintain a realistic expectation of what the investigation can hope to achieve and to open a dialogue. The main steps in the assessment are: (1) identifying cases; (2) determining the other parameters of the investigation; (3) statistically assessing the cluster; (4) examining potential exposures and assessing their biological plausibility; and (5) determining the overall significance of the cluster. The approach is illustrated throughout by examples.

A study of migraine and its effects in a working population.

The objective of this study was to determine the prevalence of migraine and its impact in a working population. A random sample of 476 employees in a chemical industry research and commercial centre took part in this cross-sectional questionnaire-based study. The questionnaire assessed the past-year prevalence of migraine, frequency and duration of episodes, effect on work and sickness absence, use and efficacy of medication and possible 'trigger factors'. Migraine prevalence was 23.2% in women and 11.6% in men. Migraineurs reported significantly more headache-related sickness absence, but did not have significantly more recorded sickness absence overall than did non-migraineurs. Of the migraineurs, 42% had never sought medical advice regarding headaches and most used non-prescription medication. Migraine is common in the study population, resulting in sickness absence and work disruption, although migraineurs have little if any more sickness absence than others. Migraineurs' use of medication is sub-optimal, and occupational health departments could assist them with education and advice.