Update to Gage and O'Connor's “Nutrition and the Variation in Level and Age Patterns of Mortality” (1994)

Abstract

It is widely assumed that nutrition influences the level of mortality. However, the association of nutrition and mortality is not linear; improved nutrition is associated with lower mortality when infectious causes of death dominate, but overnutrition, particularly with respect to the consumption of carbohydrates and fats, is often associated with increased chronic disease mortality. It is also possible that nutrition influences the age patterns of mortality. The age patterns of mortality are known to vary geographically among the world’s populations (Coale and Demeny 1966). Historically, these patterns tend to be geographically consistent even as the level of mortality declines. The cause of this human variation is under studied. Preston (1976) argued that the proximate causes of this variation result from varying geographic distributions of causes of death. Variation in nutrition may be responsible for some of this variation, possibly through influences on cause of death. The objective of our 1994 paper was to demonstrate the statistical association of the level of nutrition and dietary components on the overall level of mortality and the age patterns of mortality. For our 1994 paper we collected a worldwide sample of 341 life tables from 96 countries for the period 1952–1975 and matched them with standard national food balance sheet data for each country. One hundred seventyone tables were for males and 170 were for females; 1 female life table was excluded as defective. Expectation of life at birth in this sample ranged from 31.7 to 75.9 years. The independent variables included total calories and a principal components analysis of diet. In this case the components were interpretable as (1) a meat component, high in protein and fats, (2) carbohydrates, and (3) fats versus proteins. Standard regression analyses indicated that the international variation in nutrition was closely associated with the international variation in mortality. More than 50% of the variation was explained by these regressions, with respect to both level of mortality and the age patterns of mortality. The results indicated that total calories was positively related to expectation of life and was a better indicator than the percentage of caloric requirement. The analysis using dietary 1