[Iodine and vitamin status, body composition in older persons living in Republic of Sakha (Yakutia)].

Reduced iodine status was observed in the vast majority of elderly indigenous residents of Yakutia.

• 92.5% of subjects had iodine excretion <100 µg/l
• Study included 53 women and 8 men aged 61-95 years (median 75 years)
• Iodine concentration in daily urine was determined by stripping voltammetry
• Examination was conducted in autumn as a one-time cross-sectional assessment

Vitamin B2 (riboflavin) deficiency was found in nearly one-third of elderly subjects.

• 31.9% of subjects had riboflavin levels <5 ng/ml
• Riboflavin was determined by fluorimetric titration with riboflavin-binding apoprotein
• Combined deficiency of 3 micronutrients (most often iodine, vitamin B2, and β-carotene) was detected in 14.9% of subjects

Vitamin E deficiency and low carotenoid status were present in a minority of subjects, while all subjects had adequate vitamin A status.

• 6.1% of subjects had vitamin E (α + γ-tocopherols) levels <0.8 mg/dl
• 22.4% of subjects had β-carotene levels <10 µg/dl
• All subjects were provided with vitamin A, with retinol levels >30 µg/dl in every individual
• Retinol, α- and γ-tocopherols, and carotenoids were measured by reversed-phase HPLC

Moderate (not mild) iodine deficiency was detected more often in elderly women aged ≥75 years compared to women aged 60-74 years, indicating that iodine deficiency worsens with age.

• Difference between age subgroups was statistically significant (p<0.05)
• Vitamin B2 deficiency was detected less often in the older subgroup (≥75 years) compared to the younger subgroup (60-74 years), also at p<0.05

There were positive correlations between age of women and serum β-carotene level, and between α-tocopherol and both γ-tocopherol and β-carotene concentrations.

• Positive relationship between age and serum β-carotene level was significant at p<0.05
• Positive relationship between α-tocopherol concentration and γ-tocopherol level was significant at p<0.05
• Positive relationship between α-tocopherol concentration and β-carotene level was significant at p<0.05

Serum retinol level was negatively correlated with multiple body composition indices related to lean and skeletal mass in women.

• Negative correlation with extracellular water component (ECW): r = -0.466, p=0.002
• Negative correlation with minerals component: r = -0.420, p=0.006
• Negative correlation with bone mineral component (BMC): r = -0.405, p=0.009
• Negative correlation with soft lean mass (SLM): r = -0.408, p=0.008
• Negative correlation with fat free mass (FFM): r = -0.433, p=0.005
• Negative correlation with skeletal muscle mass (SMM): r = -0.398, p=0.010

Women with the highest serum retinol levels (quartile IV: 76.3–110.9 µg/dL) had significantly lower lean body composition parameters compared to women with lower retinol levels.

• In quartile IV, mass of ECW, minerals, BMC, SLM, FFM, and SMM were significantly lower (p<0.05) than in subjects with retinol levels in quartiles I and II (30–63 µg/dL)
• Body composition was assessed using bioelectrical impedance analysis (BIA) with the InBody S10 analyzer
• Elevated serum retinol (>80 µg/dl) was associated with negative changes in body composition parameters associated with aging

The authors propose that serum retinol levels above the upper norm limit should be considered a diagnostically significant marker of increased risk of sarcopenia in elderly individuals.

• Elevated retinol >80 µg/dl in women aged ≥60 years was associated with negative body composition changes
• The authors call for correcting excess vitamin A intake to prevent age-related alimentary diseases in elderly people living in Yakutia
• This recommendation is based on the observed inverse associations between high retinol and lean mass parameters