Objectives: Moderate alcohol consumption has been associated with decreased systemic lupus erythematosus risk, but the biologic basis for this association is unknown. We aimed to determine whether moderate alcohol consumption was associated with lower concentrations of systemic lupus erythematosus-associated chemokines/cytokines in an ongoing cohort of female nurses without systemic lupus erythematosus, and whether the association was modified by the presence of systemic lupus erythematosus-related autoantibodies.
Methods: About 25% of participants from the Nurses' Health Study (n = 121,700 women) and Nurses' Health Study 2 (n = 116,429) donated a blood sample; of these, 1177 women were without systemic lupus erythematosus at time of donation. Cumulative average and current (within 4 years) intakes of beer, wine or liquor were assessed from pre-blood draw questionnaires. Chemokine/cytokine concentrations (stem cell factor, B-lymphocyte stimulator, interferon-inducible protein-10, interferon-alpha, interleukin-10) and antibodies against dsDNA and extractable nuclear antigens were obtained using enzyme-linked immunosorbent assays. Antinuclear antibodies were detected by indirect immunofluorescence on HEp-2 cells.
Results: At blood draw, the women's mean age was 56 years and 22% were antinuclear antibody positive; 36% were African-American. About half (46%) reported consuming 0-5 g/day of alcohol. Stem cell factor levels were 0.5% lower (p < 0.0001) for every gram per day increase in cumulative average alcohol consumption. Women who consumed >5 g/day had mean stem cell factor levels 7% lower (p = 0.002) than non-drinkers. Other cytokines were not significantly associated with alcohol intake. Autoantibody status did not modify observed associations.
Conclusion: In this study of female nurses, moderate alcohol consumption was associated with lower stem cell factor levels, suggesting a plausible mechanism through which alcohol may lower systemic lupus erythematosus risk might be by decreasing circulating stem cell factor.
Keywords: Lupus; SCF; alcohol; biomarker; chemokine; cytokine; epidemiology; risk factor.