In addition to age and gender, we controlled for a number of variables that are known to have an effect on IL-6: current smoking status (smokers [23%] versus never/former [77%]), BMI derived from staff-assessed weight and height (M=24.77, SD=4.42), aspirin use within the last two weeks (8%), and disease burden. Disease burden was defined as the sum of diseases or disorders participants were currently enduring from 16 different classes of disease (e.g., neurological, immunological). In the current sample, disease burden ranged from 0 to 9, out of a possible 16 (median = 1). In the current sample, IL-6 correlated .28 (p < .01) with age, .05 (p < .01) with sex, .27 (p < .01) with BMI, .03 (p < .05) with smoking, .03 (p < .05) with disease burden, and .02 (ns) with aspirin use.
