The present invention provides a compound which functions as a selective vitamin D receptor modulator and has action-selectivity or tissue-selectivity such that it does not induce hypercalcemia but causes other effects. There is provided a compound represented by formula (I), a solvate thereof or a prodrug thereof. wherein m and n each independently represent 1 or 0； R represents a hydrogen atom or an alkyl group； Y represents an ethane-1,1-diyl group or an ethyne-1,2-diyl group； and Z 1 represents a hydrogen atom and Z 2 represents a hydroxyalkoxy group, or Z 1 and Z 2 jointly form a methylene group.
