Effects of allostatic load on the social gradient in ischaemic heart disease and periodontal disease: evidence from the Third National Health and Nutrition Examination Survey

Introduction: Psychosocial stress and allostatic load have been postulated as a mechanism explaining socioeconomic inequalities in general and oral health. This study tested whether markers of allostatic load are associated with both ischaemic heart disease and periodontal disease and whether they affect education and income gradients for both conditions. Methods: Data are from the Third National Health and Nutrition Examination Survey, conducted in the United States from 1988 to 1994. Ischaemic heart disease was determined by the presence of angina or diagnosis of heart attack. Four variables were used for periodontal disease. Individual and aggregate markers of allostatic load were used. Results: Allostatic load ( both aggregate and most individual markers) was associated with higher probabilities of all examined health outcomes. Adjusting for markers of allostatic load attenuated education and income gradients in both ischaemic heart disease and periodontal disease. The relationship between socioeconomic position and the examined health outcomes remained significant. Conclusion: Indicators of allostatic load were associated with ischaemic heart disease and periodontal disease and had a mediating effect partly explaining the social gradients in both diseases. The results suggest a possible common stress pathway linking socioeconomic position to both conditions.