Background: Obesity stigma is prevalent in the US. General discrimination has been shown to trigger a multi-system physiological dysregulation collectively referred to as allostatic load (AL), which independently predicts cardiovascular disease morbidity and mortality. However, it remains unclear whether weight-related discrimination influences AL. We aimed to examine the prospective associations between weight-related discrimination and AL and its individual systems among adults aged 25-75y participating in the national Midlife Development in the US (MIDUS) study over 10-years.
Methods: Participants from the MIDUS Biomarker Substudy with self-reported information on weight discrimination were analyzed (n=986). At baseline and at 10-years follow-up, participants were asked about the frequency (never, rarely, sometimes, often) of perceived weight discrimination across nine scenarios. A continuous score assigned 1-2 points for discrimination experienced ‘sometimes’ or ‘often’, and an average of the two values at baseline and 10-years were used to estimate long-term discrimination. An AL score (range 0-7) represented the sum of the proportion of 24 dysregulated biomarkers or corresponding medication use within each of 7 systems (cardiovascular, sympathetic and parasympathetic nervous systems, hypothalamic pituitary axis, inflammatory, lipid and general metabolic activity, and glucose metabolism). Estimated relative risks (RR) were obtained from multivariable models adjusted for age, sex, race, education, household income, smoking, physical activity, race and sex discrimination, and baseline BMI.
Results: Over 41% of the sample was obese, and 6% reported weight discrimination at 10-year follow-up. Both baseline and long-term perceived weight discrimination were associated with more than double the risk of high AL in final multivariable models (RR: 2.06, 95%CI: 1.20, 3.52 for baseline; 2.16, 95%CI: 1.39, 3.36 for long-term discrimination). The associations remained significant when the continuous weight discrimination score was assessed (β=0.11, p=0.01 for baseline; β=0.19, p=0.0001 for long-term discrimination). In sensitivity analyses, when BMI and waist:hip ratio were excluded from the AL definition, long-term weight discrimination remained associated with a 62% greater risk of high AL (1.62, 95%CI: 1.01, 2.62). Weight discrimination was significantly associated with metabolic/lipid dysregulation (1.56, 95%CI: 1.03, 2.41), glucose metabolism (1.99, 95% CI: 1.34, 2.96), and inflammatory parameters (1.76. 95% CI: 1.22, 2.54), but not with the other systems.
Conclusions: Perceived weight discrimination doubles the risk of high AL. Public health campaigns and individual patient counseling that avoid obesity stigma may help improve obesity-related morbidity and mortality by modulating multi-system physiological dysregulation.