Ethnic and gender differences in rates of congenital adrenal hyperplasia in Western Australia over a 21 year period

• Published in: Journal of paediatrics and child health Vol. 48; no. 11; pp. 1029 - 1032
• Main Authors: Shetty, Vinutha B, Bower, Carol, Jones, Timothy W, Lewis, Barry D, Davis, Elizabeth A
• Format: Journal Article
• Language: English
• Published: Melbourne, Australia Blackwell Publishing Asia 01.11.2012; Blackwell Publishing Ltd
• Subjects: Adolescent; Adrenal glands; Adrenal Hyperplasia, Congenital - epidemiology; Adrenal Hyperplasia, Congenital - ethnology; Adrenal Hyperplasia, Congenital - physiopathology; Child; Child, Preschool; Confidence Intervals; congenital adrenal hyperplasia; Congenital diseases; Ethnicity; Female; Gender; Humans; Incidence; Male; newborn screening; Oceanic Ancestry Group; Retrospective Studies; Sex Distribution; Western Australia; Western Australia - epidemiology; Young Adult; Western Australia; Western Australia Australia
• DOI: 10.1111/j.1440-1754.2012.02584.x
• ISSN: 1034-4810

Aim:  To evaluate the incidence, sex distribution, ethnicity, age at diagnosis, clinical presentation and morbidity of all childhood‐onset congenital adrenal hyperplasia (CAH) cases in Western Australia (WA) between 1990 and 2010, a state where newborn screening for CAH is not in place. Methods:  The total number of all known CAH cases was identified. Case files were reviewed retrospectively to determine clinical details. Classical CAH (C‐CAH) was defined as patients presenting before 6 months of age and non‐classical (NC‐CAH) as presenting after 6 months. Results:  Of the 41 CAH cases (26 female) born in WA, 5(12.2%) were of Aboriginal ethnicity. CAH was due to 21‐hydroxylase deficiency in 40 cases. Of those with 21‐hydroxylase deficiency, 37 were C‐CAH (25 female) and 3 NC‐CAH (all male). The incidence of C‐CAH in WA was estimated to be 0.67 per 10 000 live births (1:14 869). The incidence rate ratio of Aboriginal compared with non‐Aboriginal C‐CAH was 2.45 (95% confidence interval 0.96–6.29). The mean age of diagnosis of C‐CAH cases was lower in females (8.9 ± 2.5 days) compared to males (23.4 ± 9.8 days). Among these males, 72.7% presented initially with adrenal crisis. Conclusion:  The estimated incidence of classical CAH is similar to composite worldwide data. The increased female‐to‐male ratio is not in keeping with the expected sex distribution seen in a recessively inherited disease. The delayed diagnosis in males, with a significant proportion presenting with adrenal crisis, could be avoided with newborn screening. The higher rate of CAH in patients with Aboriginal ethnicity is a novel observation.