title: The contribution of rectangularization to the secular increase of life expectancy: an empirical study.
abstract: BACKGROUND
  In low-mortality countries, life expectancy is increasing steadily. This increase can be disentangled into two separate components: the delayed incidence of death (i.e. the rectangularization of the survival curve) and the shift of maximal age at death to the right (i.e. the extension of longevity).
  
  
  METHODS
  We studied the secular increase of life expectancy at age 50 in nine European countries between 1922 and 2006. The respective contributions of rectangularization and longevity to increasing life expectancy are quantified with a specific tool.
  
  
  RESULTS
  For men, an acceleration of rectangularization was observed in the 1980s in all nine countries, whereas a deceleration occurred among women in six countries in the 1960s. These diverging trends are likely to reflect the gender-specific trends in smoking. As for longevity, the extension was steady from 1922 in both genders in almost all countries. The gain of years due to longevity extension exceeded the gain due to rectangularization. This predominance over rectangularization was still observed during the most recent decades.
  
  
  CONCLUSIONS
  Disentangling life expectancy into components offers new insights into the underlying mechanisms and possible determinants. Rectangularization mainly reflects the secular changes of the known determinants of early mortality, including smoking. Explaining the increase of maximal age at death is a more complex challenge. It might be related to slow and lifelong changes in the socio-economic environment and lifestyles as well as population composition. The still increasing longevity does not suggest that we are approaching any upper limit of human longevity.
authors.affiliation: Institute of Social and Preventive Medicine (IUMSP), Lausanne University Hospital, Lausanne, Switzerland.
authors.forename: Isabelle A
authors.initials: IA
authors.lastname: Rossi
authors.forename: Valentin
authors.initials: V
authors.lastname: Rousson
authors.forename: Fred
authors.initials: F
authors.lastname: Paccaud
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002423:Cause of Death / Q000639:trends; D005060:Europe / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D008017:Life Expectancy / Q000639:trends*; D015993:Life Tables; D008136:Longevity; D008297:Male; D008875:Middle Aged; D009026:Mortality / Q000639:trends*; D012737:Sex Factors; D012907:Smoking / Q000453:epidemiology; D013534:Survival; D016019:Survival Analysis