	Year	Sample size	Population studied	Primary headache (%)	Migraine (%)	TTH (%)	CDH (%)
Osuntokun [9]	1982	903	GP*	ns^β	4.6	ns^β	ns^β
Osuntokun [11]	1992	18,954	GP*	51	5	ns^β	ns^β
Longe [10]	1988	2925	GP*	ns^β	6.3	ns^β	ns^β
Orji [12]	1997	4398	Children	ns^β	6.4	ns^β	ns^β
Kolawale [3]	2009	1513	USt**	ns^β	29.9	ns^β	ns^β
Ojini [7] Ofovwe [14]	2009 2010	523 1679	MS*** SS^##	46 19.5	6.4 13.5	18.1 ns^β	ns^β ns^β
Oshinaike [8]	2013	402	HW^#	39.3	7.4	28.6	ns^β
Onwuekwe [6]	2014	133	HW^#	64.7	ns	ns^β	ns^β
Ezeala-Adikaibe [1]	2012	180	MS***	88.3	18.1	36.8	17
Ezeala-Adikaibe [13]	2014	940	GP*	66.7	6.4	13.8	ns^β
Ezeala-Adikaibe^δ	2016	499	MNS***	89.9	8.9	22.9	8.5