title: Interaction between education and income on the risk of all-cause mortality: prospective results from the MOLI-SANI study.
abstract: OBJECTIVE
  To investigate the separate and inter-related associations of education and household income in relation to all-cause mortality.
  
  
  METHODS
  Prospective study on 16,247 men and women (≥35 years), a sub-sample of the MOLI-SANI cohort that had been randomly recruited within an Italian general population. Both education and income were used as categorical variables. Hazard ratios (HR) were calculated by Cox-proportional hazard models.
  
  
  RESULTS
  Over a median follow-up of 7.7 years (125,016 person-years), 694 deaths were ascertained. Either education (HR = 0.68; 95 % CI 0.51-0.91) or income (HR = 0.57; 0.42-0.77) was inversely associated with mortality. After simultaneous adjustment, the association of education appeared to be largely explained by income. A significant interaction between both variables was found (p = 0.0078). The inverse association with mortality was stronger when a higher income was combined with a higher educational level (HR = 0.59; 0.38-0.92 for the highest combination of the two indicators).
  
  
  CONCLUSIONS
  Either education or income was the predictor of mortality in a large sample of the Italian population. The two variables significantly interacted and the inverse association of income with mortality tended to be stronger within higher education groups.
authors.affiliation: Department of Epidemiology and Prevention, IRCCS Istituto Neurologico Mediterraneo NEUROMED, Pozzilli, IS, Italy. marialaura.bonaccio@neuromed.it.
authors.forename: Marialaura
authors.initials: M
authors.lastname: Bonaccio
authors.affiliation: Department of Epidemiology and Prevention, IRCCS Istituto Neurologico Mediterraneo NEUROMED, Pozzilli, IS, Italy.
authors.forename: Augusto
authors.initials: A
authors.lastname: Di Castelnuovo
authors.affiliation: Department of Epidemiology and Prevention, IRCCS Istituto Neurologico Mediterraneo NEUROMED, Pozzilli, IS, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Costanzo
authors.affiliation: Department of Epidemiology and Prevention, IRCCS Istituto Neurologico Mediterraneo NEUROMED, Pozzilli, IS, Italy.
authors.forename: Mariarosaria
authors.initials: M
authors.lastname: Persichillo
authors.affiliation: Department of Epidemiology and Prevention, IRCCS Istituto Neurologico Mediterraneo NEUROMED, Pozzilli, IS, Italy.
authors.forename: Maria Benedetta
authors.initials: MB
authors.lastname: Donati
authors.affiliation: Department of Epidemiology and Prevention, IRCCS Istituto Neurologico Mediterraneo NEUROMED, Pozzilli, IS, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: de Gaetano
authors.affiliation: Department of Epidemiology and Prevention, IRCCS Istituto Neurologico Mediterraneo NEUROMED, Pozzilli, IS, Italy.
authors.forename: Licia
authors.initials: L
authors.lastname: Iacoviello
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002423:Cause of Death; D004522:Educational Status; D005260:Female; D015438:Health Behavior; D006801:Humans; D007182:Income / Q000706:statistics & numerical data*; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009026:Mortality; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D012959:Socioeconomic Factors
keywords: Education; Income; Interaction; Mortality