Exploring ethnic and geographic disparities in polydactyly incidence in New Zealand 2010-2022

Polydactyly is a common congenital anomaly that can affect both the upper and lower limbs. Current literature in the field is lacking, but the available data show significant ethnic variation around the world. There has not been a study characterizing the incidence of polydactyly in Oceania and the Pacific Islands. The investigators aim to measure the burden of polydactyly in New Zealand and influence improvements in the provision of the healthcare system.

The prevalence of polydactyly from 2010 to 2022 in New Zealand was calculated as the number of births specific to each year per 10 000 live births. The investigators further conducted analyses to calculate the proportions of polydactyly by sex, ethnicity, geographical region and access to Plastic and Hand Surgical services.

The total number of live births with polydactyly in New Zealand from 2010 to 2022 was 858, or 13.0 per 10 000 live births. The incidence proportion varied significantly depending on gender, ethnicity and geographical region. European populations had a lower incidence of 6.3 per 10 000 births (95% CI of 5.6-7.0), while Māori and Pacific populations had incidences of 9.9 per 10 000 births (95% CI of 8.7-11.3) and 10.2 per 10 000 births (95% CI of 8.5-12.1), respectively.

The results of this study demonstrate variations in polydactyly incidence dependent on several factors, including gender, ethnicity and geographic region. The incidence proportion of polydactyly in Māori, Pacific and Asian populations is higher than that of the European population in New Zealand.