The epidemiology of plunging ranula in South Auckland.
Estimate the incidence rate and provide basic descriptive epidemiologic characteristics of plunging ranulas in a multi-ethnic population.



Case series with chart review.



The study group comprised all Counties Manukau Health (CMH, Manukau City, Auckland, New Zealand) patients presenting to the CMH Department of Otolaryngology with a diagnosis of plunging ranula from January 2001 to December 2013, as recorded in the departmental case register. Non-CMH domicile patients were excluded. South Auckland comprised the base population, as serviced by CMH. The 2006 New Zealand census data was used for population demographics.



A total of 134 cases of plunging ranula were identified. The overall annual crude incidence rate was 2.4 per 100,000 person-years. The gender specific incidence rate for males was 3.2 per 100,000 (95% confidence interval [CI]: 2.5. 3.9) and for females was 2.0 per 100,000 (95% CI: 1.5, 2.6). The overall age-adjusted annual incidence rate was 2.6 per 100,000 (95% CI: 2.1, 3.0). The age-adjusted incidence was highest among Maori (6.7 per 100,000, 95% CI 4.9, 8.4), followed by Pacific Island (4.4 per 100,000, 95% CI 3.2, 5.6), Asian (0.7 per 100,000, 95% CI 0.2, 1.2), and European population (0.6 per 100,000, 95% CI 0.3, 0.8).



We have quantified for the first time the age-specific and age-adjusted incidence rates for plunging ranula by gender and ethnicity. The results show a likely underlying genetic predisposition for this condition, possibly with a superimposed environmental acquired factor relating to external, minor blunt trauma to the neck.



4. Laryngoscope, 126:2739-2743, 2016.
Department of Otolaryngology-Head and Neck Surgery, Counties Manukau Health, Auckland, New Zealand.
Seung Joon
SJ
Chin
Research and Evaluation Office, Health Intelligent and Informatics, Ko Awatea Counties Manukau Health, Auckland, New Zealand.
Irene S L
IS
Zeng
Department of Otolaryngology-Head and Neck Surgery, Counties Manukau Health, Auckland, New Zealand.
Randall P
RP
Morton
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D009333:Neck / Q000473:pathology*; D009520:New Zealand / Q000453:epidemiology; D011900:Ranula / Q000453:epidemiology* / Q000208:ethnology; D012307:Risk Factors; D013364:Submandibular Gland Diseases / Q000453:epidemiology* / Q000208:ethnology; D055815:Young Adult
Plunging ranula; cystic; epidemiology; incidence; neck lesions; ranula