Deprivation, Ethnicity and Eczema: Understanding Associations for Childhood Bone and Joint Infection.

BACKGROUND

Rates of childhood bone and joint infection (BJI) in New Zealand (NZ) are among the highest in the world, with a disproportionate burden experienced by Māori and Pacific children. Eczema, also inequitably distributed by ethnicity, is a potential risk factor for BJI. This study describes the recent incidence of BJI and investigates disease risk secondary to eczema.

METHODS

BJI cases were children aged </= 15 years admitted with acute haematogenous osteomyelitis (AHO) or septic arthritis (SA) between 2018 and 2023 in the Auckland region. Data were obtained on eczema status, ethnicity and area-based socioeconomic deprivation. BJI incidence was estimated using the 2018 Census. A retrospective case-control study was undertaken to determine the association between eczema and BJI. Ethnicity-matched controls were identified from the nationally representative NZ Health Survey.

RESULTS

This study identified 563 cases and 8840 ethnicity-matched controls. Incidence of AHO remains higher for Māori (26.7/100 000) and Pacific (38.5/100 000) compared with European children (17/100 000). Eczema was seen more frequently in BJI cases (30% of BJI cases vs. 24% of NZHS controls (p = 0.0007)). For NZ Māori and Pacific children, a diagnosis of eczema increased the odds of developing BJI (Pacific aOR = 1.6, 95% CI: 1.1-2.3, Māori aOR = 1.6, 1.1-2.4). Pacific children with BJI were more likely than controls to reside in areas of greater socioeconomic deprivation (aOR 1.88, 95% CI: 1.3-2.5). European children were more likely to reside in areas of least socioeconomic deprivation (OR 2.3, 95% CI: 1.7-3.1).

CONCLUSIONS

Childhood BJI remains inequitably distributed by ethnicity. Eczema may be a suitable focus for strategies to lower disease risk.