MORBIDITY FOLLOW-UP-STUDY OF BASF EMPLOYEES EXPOSED TO 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN (TCDD) AFTER A 1953 CHEMICAL REACTOR INCIDENT

Objective-The aim was to examine the long term morbidity experience of men exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Methods-A retrospective cohort morbidity study of 158 men first exposed to TCDD between 17 November 1953 and 16 November 1954 subdivided by chloracne state and back calculated TCDD blood lipid concentration, and 161 refe rents. Cause specific illness absence and admissions to hospital were examined between 1953 and 1989. Results-On an ever or never basis, thy roid disease and appendicitis were diagnosed more often in the study g roup; these diseases were not differentially distributed by chloracne state, but were increased in the high TCDD subgroup. An 18% increase i n total illness episodes was also seen (p = 0.002); illness rates incr eased with severity of chloracne and higher TCDD concentration within the chloracne subgroup. There were increases in infectious and parasit ic diseases (primarily ill defined intestinal infections), disorders o f the peripheral nervous system and sense organs, upper respiratory tr act infections, and other skin diseases. Several of these increases co rrelated with chloracne state and infectious disease episodes increase d with higher TCDD concentration as well. Occurrences of mental disord ers correlated with severity of chloracne, but not TCDD concentration. Benign and unspecified neoplasms were marginally increased in the sev ere chloracne and high TCDD subgroups. Chronic liver disease was margi nally increased in the high TCDD subgroup. Findings relative to occurr ence of ulcers, chronic lung disease, and kidney and metabolic disorde rs were unremarkable. Discussion-For various conditions, increased ill ness episodes were seen among TCDD exposed employees compared with ref erents and were associated with either or bath chloracne severity and back calculated TCDD concentration. The results are derived from insur ance data; hence, it is possible that heightened awareness and persona l health concerns led to greater utilisation of medical services in th e exposed group. The findings based on TCDD concentration should be le ss subject to this potential bias.