Secular trends in the association of socio-economic position with self-reported dietary attributes and biomarkers in the US population: National Health and Nutrition Examination Survey (NHANES) 1971-1975 to NHANES 1999-2002

Public Health Nutr. 2007 Feb;10(2):158-67. doi: 10.1017/S1368980007246749.


Objective: Recent reports suggest persistence of health disparities related to socio-economic position (SEP). To understand if diet may be a contributor to these trends, we examined secular trends in the association of diet and indicators of SEP from 1971-1975 to 1999-2002.

Design: We used data from the National Health and Nutrition Examination Surveys (NHANES) I (1971-1975), II (1976-1980), III (1988-1994) and 1999-2002 to examine the independent associations of poverty income ratio (PIR) and education with diet and biomarkers of diet and disease in 25-74-year-olds (n = 36,600). We used logistic and linear regression methods to adjust for multiple covariates and survey design to examine these associations.

Results: A large PIR differential in the likelihood of reporting a fruit or all five food groups and vitamin C intake, and an education differential in likelihood of obesity and carbohydrate intake, was noted in 1971-1975 but narrowed in 1999-2002 (P < 0.007). The positive association of education with intake of a fruit, vegetable or all five food groups, vitamins A and C, calcium and potassium intake remained unchanged across surveys (P < 0.001). Similarly, the positive association of PIR with the amount of foods and intakes of energy and potassium remained unchanged over three decades (P < 0.001). The education and the PIR differential in energy density, and the PIR differential in the likelihood of obesity, persisted over the period of the four surveys (P < 0.001).

Conclusions: Persistence of unfavourable dietary and biomarker profiles in Americans with low income and education suggests continued need for improvement in the quality of diets of these high-risk groups.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural

MeSH terms

  • Adult
  • Aged
  • Body Mass Index
  • Diet / trends*
  • Educational Status
  • Female
  • Humans
  • Income*
  • Linear Models
  • Logistic Models
  • Male
  • Middle Aged
  • Nutrition Surveys*
  • Obesity / epidemiology*
  • Obesity / etiology
  • Self Disclosure
  • Social Class*
  • Socioeconomic Factors
  • United States