WHOOPING-COUGH AND PARKINSONS-DISEASE

Background. We reported high levodopa use and prevalences of Parkinson 's Disease (PD) in periodically, time-clustered, Icelandic cohorts bor n after major whooping cough epidemics (MWCE). Methods. In order to qu antify a possible relationship between age at first post-birth MWCE an d risk of PD we: 1) calculated cumulative incidences of PD during the period 1954-1963 in one-year Icelandic cohorts born between 1869 and 1 927, using raw material from a reported survey; 2) identified MWCE fro m 1869 onwards in Iceland; 3) estimated cohort ages at onset of incide nce period and at first MWCE; and 4) combined the above-mentioned info rmation using log-linear models. In addition, we studied the prevalenc e of levodopa users in Icelandic birth cohorts during a recent period. Results. The curves of the above-mentioned incidences and prevalences in one-year birth-cohorts showed: 1) a similar, age-related, inverted V profile; and 2) a systematic notchy pattern, with peak values for o ne or both measurements for cohorts born during or after each of nine MWCE identified during the period 1869-1927. When 13 cohorts born in y ears with MWCE were excluded from the analysis, the risk of PD rose wi th age at first defined MWCE, with the linear increase being 8.4% per year (95% CI:-0.1-18.3%). Conclusions. These results are consistent wi th reported effects of age at exposure in animal models of toxic parki nsonism, age-related changes in the dopamine receptor-GPT-binding prot ein-adenylatecyclase system observed in rats treated with pertussis to xin, and some PD epidemiological features. They suggest that pertussis neurotoxicity could be causally related to PD worldwide.