Association between Serum 25-Hydroxyvitamin D Level and Insulin Resistance in a Rural Population

Abstract

PurposeA low serum 25-hydroxyvitamin D [25(OH)D] level in the blood has been correlated with an increased risk of diabetes mellitus; however, the association between serum 25(OH)D level and insulin resistance has not been established in a Korean rural population. The aim of this study was to investigate the independent association between serum 25(OH)D level and insulin resistance in rural Korean adults.Materials and MethodsThis study used data from the Korean Genome Epidemiology Study-Kangwha Study. In the 2011 study, 1200 adults completed health examinations. In an ancillary study, serum 25(OH)D level was measured in a subsample (n=813). After excluding those taking vitamin D supplements, a cross-sectional analysis was carried out on 807 participants (324 men and 483 women) aged 40 to 89 years old. Measured from overnight fasting blood samples, glucose and insulin levels were used to calculate the homeostasis model assessment for insulin resistance (HOMA-IR). Measures of glucose, insulin, and HOMA-IR were log-transformed for parametric tests.ResultsSerum 25(OH)D level was inversely associated with HOMA-IR (β=-0.003, p=0.039) in a univariate analysis. However, the association was not significant after adjustment for sex and age (β=-0.002, p=0.123) or after adjustment for sex, age, body mass index, smoking status, alcohol intake, and regular exercise (β=-0.003, p=0.247).ConclusionOur findings suggest that vitamin D is not independently associated with insulin resistance in Korean men and women.

The effect of sex hormone-binding globulin (SHBG) protein polymorphism on the levels of SHBG, testosterone, and insulin in healthy Indonesian men

“…The mean level of insulin in this study was 6.7 uIU/mL [ Table 3], which was equal with the results of the study on 324 Korean men. [41] Serum insulin level between normal SHBG phenotype when compared with variant SHBG phenotype was different (p < 0.05) [ Table 3]. These data indicate that serum insulin level is influenced by proteins polymorphism of SHBG.…”

Investigation of vitamin D status and its correlation with insulin resistance in a Chinese population

“…In an East Asian population of 136 healthy Japanese males, Sun et al (36) found that the median 25(OH)D concentration was 36•5 nmol/l and that 78•7 % of the men were 25(OH)D deficient (<50 nmol/l). In 807 rural Korean adults, the mean serum 25(OH)D concentration was 64•5 nmol/l (75•25 nmol/l in men and 57•25 nmol/l in women) (12) . Choi et al (37) studied 260 Korean adolescents and found a mean concentration of 25(OH)D of 39•5 nmol/l (42•5 nmol/l in males and 36 nmol/l in females), while Tao et al (38) found that the mean 25(OH)D concentration was 51•75 nmol/l in 1382 non-diabetic Chinese female participants.…”

“…However, in recent years, increasing evidence has indicated that 25(OH)D may have additional functional roles. Several studies have indicated an association between low concentrations of serum 25(OH)D and insulin resistance (4)(5)(6) , although this relationship has been controversial (7)(8)(9)(10)(11)(12) . Moreover, BMI, blood glucose status and season are also known to influence the relationship between 25(OH)D and insulin resistance.…”

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“…There was an association between the severity of hypovitaminosis D and obesity 16 . The present study had showed that there is a significant negative correlation between obesity and hypovitaminosis.…”