Table 1.
Bradford Hill criteria for assessing causation [11] and their adaptation to the case of onchocerciasis and epilepsy.
Fig 1.
Selection of eligible studies.
Table 2.
Case-control studies investigating the association between onchocerciasis and nodding syndrome.
Table 3.
Case-control studies in meso- and hyper-endemic areas on the onchocerciasis-epilepsy relationship (ranked according to increasing duration of onchocerciasis control.
Fig 2.
The ages of village residents at epilepsy onset (A) in non-onchocerciasis–endemic regions in Kilifi, Kenya and Agincourt, South Africa [50] (B) in onchocerciasis-endemic communities in Mbam, Cameroon [43], Ituri, DRC [53], and Mahenge, Tanzania [49].
Fig 3.
The ages at seizure onset in persons with neurocysticercosis (blue) and those in onchocerciasis-endemic areas (orange). Adapted from findings reported by Monteiro and colleagues [72] and by Lenaerts and colleagues [53].
Fig 4.
Comparison of age-specific crude prevalence of epilepsy in Bilomo, Mbam valley, Cameroon, 1998 (blue) versus 2017 (orange) [43]. MH, Mantel–Haenszel.