Associations between vitamin D2 and metabolic indices in institutionalized older adults -a cross-sectional study.

The institutionalized older adult population showed vitamin D deficiency with excessive caloric intake and insufficient protein and vitamin D consumption.

• Mean serum 25(OH)D concentration was 17.6±23.9 ng/mL, indicating vitamin D deficiency
• Sample consisted of 95 older adults with mean age 63±14 years
• Participants were overweight with excessive caloric intake
• Protein and vitamin D consumption were reported as insufficient based on dietary questionnaire analysis

Serum VD2 showed a significant positive correlation with insulin levels.

• Correlation coefficient r=0.87, p<0.001
• This was the strongest correlation observed among all metabolic indices tested
• The association was identified in the full sample of 95 institutionalized older adults

Serum VD2 showed significant positive correlations with adiponectin and leptin.

• Correlation with adiponectin: r=0.41, p<0.001
• Correlation with leptin: r=0.22, p=0.034
• Both adiponectin and leptin are hormones involved in energy homeostasis regulation

Serum VD2 showed a significant positive correlation with vitamin D receptor (VDR) protein.

• Correlation coefficient r=0.37, p<0.001
• VDR protein levels were measured as part of the metabolic assessment
• This association was observed in the full sample

Serum VD2 showed a significant negative correlation with non-HDL cholesterol specifically in women.

• Correlation coefficient r=-0.33, p=0.042
• This inverse relationship was observed only in the female subgroup, not reported for the full sample
• The finding suggests a possible involvement of VD2 in lipid metabolism in women

Principal component analysis and multiple regression identified PC1 and gender as significant predictors of VD2 levels in the full sample.

• Two components were extracted from PCA in the full sample
• PC1 had high loadings for insulin, leptin, and adiponectin
• Multiple regression included age, gender, medication use, and PCA components as predictors
• PC1 and gender together explained 41.6% of the variance in VD2 levels

Among participants with preserved insulin sensitivity (HOMA-IR <2.5), a single principal component explained a substantially higher proportion of variance in VD2 levels.

• HOMA-IR threshold of <2.5 was used to define preserved insulin sensitivity
• A single principal component characterized by insulin, adiponectin, and leptin explained 69.4% of the variance in VD2 levels in this subgroup
• This compares to 41.6% variance explained in the full sample, suggesting stronger VD2-metabolic hormone associations in insulin-sensitive individuals