The impact of ethnicity and its definition on diabetes prevalence: A national Australian whole-of-population study.

Aims: We assessed the extent to which using large geographic regions to group ethnicities (ancestries or countries-of-birth) masked intra-regional variation in diabetes risk.

Methods: We performed a cross-sectional analysis of the 2021 Australian National Census, which included self-reported health data. Ethnicity-specific diabetes prevalence was age/sex-standardised to a reference population of all census respondents 20 years and above.

Results: There were 17.5 million adults included in this study. Within four geographical regions, there wastwo-four-fold intra-regional variation in diabetes risk. Diabetes prevalence among people reporting a single East Asianancestry ranged from less than the Australian prevalence (Japanese 4.2%, Thai 6.1%) to twice the Australian prevalence (Filipino 12.6%). Among peoplereporting a single South/Central Asianancestry, diabetes prevalence ranged from 7.3% (Armenian) to 18.4% (Bangladeshi). Among people reporting a single Middle Eastern/North African ancestry, diabetes prevalence values rangedfrom 5.4% (Jewish) to 12.3% (Iraqi). In Oceania, the diabetes prevalence in people of Australian Aboriginal, Fijian, Maori, Samoan and Tongan ancestry was greater than the Australian prevalence(17.5%, 12.3%, 10.0%, 16.3% and 17.4%, respectively versus 6.3%).

Conclusions: There wastwo-four-fold variation in diabetes prevalence between populations within four geographical regions. Aggregating ethnicity into large geographic regional groups may incorrectly estimate diabetes risk.