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

UNLABELLED: Optimizing the micronutrient status of older adults is an important component of maintaining healthy longevity. The objective was to study gender and age characteristics of iodine, vitamin A, E, B2 and β-carotene status, as well as indicators of body component composition associated with aging in elderly indigenous people of the Republic of Sakha (Yakutia).

MATERIAL AND

METHODS

In the autumn, a one-time examination of the micronutrient status of 53 women and 8 men aged 61-95 years (median - 75 years, indigenous residents of Yakutia) was conducted. The concentration of iodine in daily urine was determined by stripping voltammetry, in blood serum the level of riboflavin (vitamin B2) was determined by the fluorimetric titration with riboflavin-binding apoprotein, retinol (vitamin A), α- and γ-tocopherols (vitamin E), carotenoids (β-carotene) - by reversed-phase HPLC. Bioelectrical impedance analysis (BIA) of body composition was performed using the InBody S10 analyzer.

RESULTS

Reduced iodine status (excretion <100 μg/l) was observed in the majority of elderly individuals - 92.5%, vitamin B2 (riboflavin <5 ng/ml) - in 31.9%, vitamin E (α + γ-tocopherols <0.8 mg/dl) - 6.1% and carotenoids (β-carotene <10 μg/dl) - 22.4%. All subjects were provided with vitamin A (retinol >30 μg/dl). Combined deficiency of 3 micronutrients (most often iodine, vitamin B2 and β-carotene) was detected in 14.9% of citizens. In a subgroup of elderly women aged ≥75 years moderate (not mild) iodine deficiency was detected more often than in women 60-74 years old, while vitamin B2 deficiency was detected less often (p<0.05). There was a positive relationship (p<0.05) between the age of women and serum β-carotene level, as well as between the concentration of α-tocopherol, on the one hand, and the levels of γ-tocopherol and β-carotene, on the other. A negative correlation was found between the serum retinol level and some BIA body composition indices: extracellular water component (ECW; -0.466, p=0.002), minerals component (-0.420, p=0.006), bone mineral component (BMC; -0.405, p=0.009), soft lean mass (SLM; -0.408, p=0.008), fat free mass (FFM; -0.433, p=0.005), and skeletal muscle mass (SMM; -0.398, p=0.010). In women with 76.3-110.9 μg/dL serum retinol level (quartile IV), the mass of the ECW, minerals and BMC, SLM, FFM and SMM were significantly lower (p<0.05) than in those examined with retinol levels in the range of 30-63 μg/dL (quartiles I and II).

CONCLUSION

Iodine and vitamin B2 deficiency are most common in elderly indigenous people of Yakutia; iodine deficiency worsens with age. In women aged ≥60 years, elevated serum retinol level (>80 μg/dl) was associated with negative changes in body composition parameters associated with aging. In elderly individuals, serum retinol levels above the upper norm limit should probably be considered as a diagnostically significant marker of increased risk of sarcopenia. The rationale for expanding measures to eliminate deficiency of iodine and B vitamins, and to correct excess vitamin A intake in order to prevent age-related alimentary diseases in elderly people living in Yakutia is substantiated.