title: Oral cavity cancer trends over the past 25 years in Hong Kong: a multidirectional statistical analysis.
abstract: BACKGROUND
  Even though oral cavity cancer (OCC; ICD 10 codes C01, C02, C03, C04, C05, and C06) ranks eleventh among the world's most common cancers, accounting for approximately 2 % of all cancers, a trend analysis of OCC in Hong Kong is lacking. Hong Kong has experienced rapid economic growth with socio-cultural and environmental change after the Second World War. This together with the collected data in the cancer registry provides interesting ground for an epidemiological study on the influence of socio-cultural and environmental factors on OCC etiology.
  
  
  METHODS
  A multidirectional statistical analysis of the OCC trends over the past 25 years was performed using the databases of the Hong Kong Cancer Registry. The age, period, and cohort (APC) modeling was applied to determine age, period, and cohort effects on OCC development. Joinpoint regression analysis was used to find secular trend changes of both age-standardized and age-specific incidence rates.
  
  
  RESULTS
  The APC model detected that OCC development in men was mainly dominated by the age effect, whereas in women an increasing linear period effect together with an age effect became evident. The joinpoint regression analysis showed a general downward trend of age-standardized incidence rates of OCC for men during the entire investigated period, whereas women demonstrated a significant upward trend from 2001 onwards.
  
  
  CONCLUSIONS
  The results suggest that OCC incidence in Hong Kong appears to be associated with cumulative risk behaviors of the population, despite considerable socio-cultural and environmental changes after the Second World War.
authors.affiliation: Discipline of Oral and Maxillofacial Surgery, Faculty of Dentistry, The University of Hong Kong, 34 Hospital Road, Sai Ying Pun, Hong Kong, SAR, PR-China. ushida.keisuke@gmail.com.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Ushida
authors.affiliation: Discipline of Dental Public Health, Faculty of Dentistry, The University of Hong Kong, 34 Hospital Road, Sai Ying Pun, Hong Kong, SAR, PR-China. mcgrathc@hku.hk.
authors.forename: Colman P
authors.initials: CP
authors.lastname: McGrath
authors.affiliation: Discipline of Dental Public Health, Faculty of Dentistry, The University of Hong Kong, 34 Hospital Road, Sai Ying Pun, Hong Kong, SAR, PR-China. hrdplcm@hku.hk.
authors.forename: Edward C M
authors.initials: EC
authors.lastname: Lo
authors.affiliation: Discipline of Oral and Maxillofacial Surgery, Faculty of Dentistry, The University of Hong Kong, 34 Hospital Road, Sai Ying Pun, Hong Kong, SAR, PR-China. zwahlen@hku.hk.
authors.forename: Roger A
authors.initials: RA
authors.lastname: Zwahlen
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D016021:Epidemiologic Studies; D005260:Female; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009062:Mouth Neoplasms / Q000453:epidemiology*; D012042:Registries; D018570:Risk Assessment; D012737:Sex Factors; D055815:Young Adult