Complex sentence: By 2006, the EA-OHP conference series became biennial, and by an agreement reached in 2008 was coordinated with the APA/NIOSH/SOHP Work, Stress, and Health conference series.
Split into simpler sentences: By 2006, the EA-OHP conference series became biennial. By way of an agreement reached in 2008, the EA-OHP now coordinates its conference series with the APA/NIOSH/SOHP Work, Stress, and Health conference series.