title: Milk consumption in relation to incidence of nasopharyngeal carcinoma in 48 countries/regions.
abstract: BACKGROUND
  Decreasing trends of nasopharyngeal carcinoma (NPC) incidence have been consistently reported in endemic populations but the etiology of NPC remains unclear. The objective of our study was to assess the international and local (Hong Kong) correlations of milk and dairy products per capita consumption with NPC incidence.
  
  
  METHODS
  We conducted an ecological study in 48 countries/regions. Age standardized incidence rates of NPC were obtained from the Cancer Incidence in Five Continents. Dairy product consumption and Human Development Index were obtained from the Food and Agriculture Organization of the United Nations and the United Nations Development Programme. Spearman correlation, multivariate analysis and time-lagged analysis were performed.
  
  
  RESULTS
  The negative correlations between milk consumption and decreased age standardized incidence rates of NPC were observed in the 48 countries/regions adjusting for Human Development Index in endemic countries/regions. In Hong Kong, multivariate analysis, after adjusting for other potential confounders, including salted fish, cigarette, vegetable consumption and socioeconomic status, showed consistently negative and significant correlations between milk consumption and NPC incidence (The strongest coefficient (β) was observed at 10-year lag in males [β = -0.439; P < 0.01] and in females [β = -0.258; P < 0.01]).
  
  
  CONCLUSIONS
  Our study showed the correlations on milk consumption per capita and against lower risk of NPC in 48 countries/regions and in Hong Kong. These hypothesis-generating results could support further studies on individual exposures and the disease.
authors.affiliation: School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 5/F, William MW Mong Block, 21 Sassoon Road, Hong Kong S.A.R., China. maizm@hku.hk.|Center for Nasopharyngeal Carcinoma Research (CNPCR), Research Grants Council Area of Excellence Scheme, The University of Hong Kong, Hong Kong S.A.R., China. maizm@hku.hk.
authors.forename: Zhi-Ming
authors.initials: ZM
authors.lastname: Mai
authors.affiliation: School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 5/F, William MW Mong Block, 21 Sassoon Road, Hong Kong S.A.R., China. lomaggie@hku.hk.|Center for Nasopharyngeal Carcinoma Research (CNPCR), Research Grants Council Area of Excellence Scheme, The University of Hong Kong, Hong Kong S.A.R., China. lomaggie@hku.hk.
authors.forename: Ching-Man
authors.initials: CM
authors.lastname: Lo
authors.affiliation: School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 5/F, William MW Mong Block, 21 Sassoon Road, Hong Kong S.A.R., China. xusunjun@hku.hk.|Center for Nasopharyngeal Carcinoma Research (CNPCR), Research Grants Council Area of Excellence Scheme, The University of Hong Kong, Hong Kong S.A.R., China. xusunjun@hku.hk.
authors.forename: Jun
authors.initials: J
authors.lastname: Xu
authors.affiliation: School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 5/F, William MW Mong Block, 21 Sassoon Road, Hong Kong S.A.R., China. kpchanaa@hku.hk.
authors.forename: King-Pan
authors.initials: KP
authors.lastname: Chan
authors.affiliation: School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 5/F, William MW Mong Block, 21 Sassoon Road, Hong Kong S.A.R., China. hrmrwcm@hku.hk.
authors.forename: Chit-Ming
authors.initials: CM
authors.lastname: Wong
authors.affiliation: Department of Clinical Oncology and Center for Cancer Research, The University of Hong Kong, Hong Kong S.A.R., China. mlilung@hku.hk.|Center for Nasopharyngeal Carcinoma Research (CNPCR), Research Grants Council Area of Excellence Scheme, The University of Hong Kong, Hong Kong S.A.R., China. mlilung@hku.hk.
authors.forename: Maria Li
authors.initials: ML
authors.lastname: Lung
authors.affiliation: School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 5/F, William MW Mong Block, 21 Sassoon Road, Hong Kong S.A.R., China. hrmrlth@hkucc.hku.hk.|Center for Nasopharyngeal Carcinoma Research (CNPCR), Research Grants Council Area of Excellence Scheme, The University of Hong Kong, Hong Kong S.A.R., China. hrmrlth@hkucc.hku.hk.
authors.forename: Tai-Hing
authors.initials: TH
authors.lastname: Lam
mesh_terms: D000328:Adult; D000818:Animals; D002277:Carcinoma; D003611:Dairy Products / Q000009:adverse effects*; D004032:Diet / Q000639:trends*; D005260:Female; D014943:Global Health; D006801:Humans; D015994:Incidence; D008297:Male; D008892:Milk / Q000009:adverse effects; D015999:Multivariate Analysis; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000453:epidemiology* / Q000209:etiology; D012044:Regression Analysis