This first Australian population-based study of environmental risk factors confirms that smoking, childhood immunological events and dietary factors play a role in IBD development; while high caffeine intake and pet ownership offer a protective effect.

IBD in HK was diagnosed at an older age, and had more complicated disease behavior than in Melbourne. Medical therapy, however, was less intense in HK. These differences may relate to real differences in disease or delayed diagnosis due to late presentation and less disease recognition in HK.

Deficiencies exist in current transition care of adolescents with IBD in Australia and New Zealand. Standardising transition care practices with strategies aimed at optimising communication, patient education, self-efficacy and adherence may improve outcomes.