Epidemiological approach to planning and development of occupational health services at a national level.

In developing the national occupational health programme in Thailand it was necessary to obtain information on workers' health to enable proper planning and implementation of the programme. A stratified sample of different types of small (up to 50 workers) and medium-sized factories (51-150 workers) located in one geographical area was selected. In all, 98 plants were surveyed and a total of 1449 workers were examined. The prevalence of diseases, many of which were work-related, was higher in the small than in the medium-sized plants. Additional information confirmed the need for controlling the multitude of health problems of these under-served workers. The Ministry of Health used this data in training primary health care workers in the small workplaces, controlling the health problems discovered, developing laboratories and drafting legislation.