Aims
The recent and ongoing worldwide expansion in prevalence of Type 2 Diabetes (T2DM) is a considerable risk to individuals, health systems and economies. The increase in prevalence has been particularly marked in the states of the Co-operation Council for the Arab States of the Gulf (GCC), and these trends are set to continue. We aimed to systematically review the current prevalence of T2DM within these states, and also within particular sub-populations.

Methods
We identified 27 published studies for review. Studies were identified by systematic database searches. Medline and Embase were searched using terms such as diabetes mellitus, non-insulin-dependent, hyperglycemia, prevalence, epidemiology and Gulf States. Our search also included scanning reference lists, contacting experts and hand-searching key journals. Studies were judged against pre-determined inclusion and exclusion criteria, and where suitable for inclusion, data extraction and quality assessment was achieved using a specifically-designed tool. All studies where prevalence of diabetes was investigated were eligible for inclusion. The inclusion criteria required that the study population be of a GCC country, but otherwise all ages, sexes and ethnicities were included, resident and migrant populations, urban and rural, of all socioeconomic and educational backgrounds. No limitations on publication type, publication status, study design or language of publication were imposed. However, we did not include secondary reports of data, such as review articles without novel data synthesis.

Conclusions
The prevalence ofT2DM is an increasing problem for all GCC states. They may therefore benefit to a relatively high degree from co-ordinated implementation of broadly consistent management strategies. Further study of prevalence in children and in national versus expatriate populations would also be useful.