Selenium status markers and their relationship with anthropometric, glycemic, and inflammatory variables in institutionalized older adults.

Selenium's role in aging is supported by its involvement in antioxidant defense, immune function, and cellular maintenance. Adequate selenium levels can contribute to healthier aging. This cross-sectional study investigated the associations of selenium status markers with anthropometric parameters, glycemic profile, and inflammatory biomarkers in 72 older adults living in nursing homes (NH). Plasma selenium levels were measured using inductively coupled plasma mass spectrometry, and selenoprotein P (SELENOP) was determined using enzyme-linked immunosorbent assay. Dietary selenium intake data were obtained by directly weighing the food at two different times, with an interval of 30 to 45 days between them. The mean age was 83 (8.6) years. The median (IQR) of plasma selenium levels was 88.20 (76.0-106.0)µg/L, for SELENOP 32.30 (29.2-33.5)ng/mL, and the mean (SD) of dietary selenium intake was 72.7 (11.9)µg/day. Overall, 65.2% of participants exhibited elevated glycated hemoglobin (HbA1c) levels. Insufficient plasma selenium levels to optimize SELENOP (< 100 μg/L) showed a significant association with being underweight (p = 0.04). Participants with low SELENOP and low dietary selenium intake had HbA1c levels above 6.4% (p = 0.05). Plasma selenium levels and dietary selenium intake were positively correlated with body mass index (ρ = 0.408, p = 0.001 and r = 0.382, p = 0.004, respectively). Selenium status markers were not associated with the inflammatory biomarkers. However, half of the population had high levels of IL-6 and TNF-α, and 98.5% had high levels of hs-CRP. In conclusion, lower plasma selenium was associated with underweight status, while reduced SELENOP and dietary selenium intake correlated with elevated HbA1c in older adults in NH.