OBJECTIVES: To estimate the number of occupational accidents that occurred in a certain municipality during a specific period of time as well as the extent of sub-registration. METHODS: The study sample was comprised of 4.782 households within the municipality of Botucatu, São Paulo occupied by a total 17,219 inhabitants on the 1st of July, 1997. In each household, an adult inhabitant was interviewed in order to identify the occurrence of occupational accidents in the three months preceding the interview. When such occurrences were identified, the injured workers were interviewed. The Cochran formula was utilized to calculate the confidence interval. RESULTS: Seventy-six individuals confirmed that they had suffered occupational accidents during these three months. In 1997, there were approximately 1,810 occupational accidents in Botucatu, according to our estimates, and the incidence of work related injuries in the population was approximately 4.1% (CI 95% 3.0%-5.3%). Thirty-nine (51.3%, CI 95% 41.1%61.6%) of the above 76 workers were not covered by the Social Security System. Consequently, their injuries were not reported for there was no legally binding obligation to fill out and emit the official registration form - Comunicação de Acidente do Trabalho (CAT) [the work injury report]. Included among the latter are civil servants and informal sector workers, such as self-employed, casual workers and others. Although the remaining 37 workers (48.7%) were covered by the Social Security System and emission of the work injury report was obligatory, 20 of the cases (54.1% CI 95% 39.4%-68.7%) had not been registered. A greater proportion of cases of sub-registration were found among those workers employed in micro, small and medium sized businesses than among those working in large firms. Only 22.4% (CI 13.8%-30.9%) of the occupational accidents reported in this study were registered by the Social Security System. CONCLUSIONS: Research findings confirm that analyses based on the number of officially registered workplace accidents are limited. It highlights the importance of utilizing other sources of data, besides the registration form for occupational accidents used currently by the Social Security System, Comunicação de Acidente do Trabalho or CAT, in order to elaborate official statistics on occupational accidents.
Accidents; Epidemiology; Underregistration; Occupational accidents registry