Prevalence and determinants of vitamin D deficiency in Iranian children and adolescents: the CASPIAN-V study.

PURPOSE: To examine the prevalence and determinants of vitamin D deficiency in Iranian children and adolescents. METHODS: We used data from a national school-based surveillance program conducted among 7-18-year-old children and adolescents living in rural and urban areas in 30 provinces of Iran. Data on student's lifestyle, health behaviors, and health status was obtained through a validated questionnaire. Serum 25-hydroxy vitamin D (25-OH-D) level was measured by chemiluminescent immunoassay. Vitamin D deficiency was defined as serum 25-OH-D concentrations < 30 ng/ml. Determinants of vitamin D deficiency were identified using logistic regression analysis. RESULTS: Data of 2,596 participants were available for this study. Prevalence of vitamin D deficiency was 71.1 % (95 % Confidence interval (CI): 69.3-72.8 %), without significant difference between boys and girls (72.0 % vs. 70.1 %, respectively, p = 0.29). In the multivariate regression model, in both genders, those who reported having sun exposure for at least 30 min/day and those taking vitamin D supplementation had lower odds for vitamin D deficiency (all p values < 0.05). In boys, obesity increased the odds of vitamin D deficiency (adjusted OR, 95 % CI: 1.57, 1.08-2.27). The association of vitamin D deficiency with other demographic characteristics and food items was not statistically significant. CONCLUSIONS: This large population-based study revealed a high frequency of hypovitaminosis D in Iranian children and adolescents. Sun exposure for at least 30 min/day and taking vitamin D supplementation may reduce the risk of vitamin D deficiency.

Association of Vitamin D Concentrations with subjective health complaints in children and adolescents: the CASPIAN-V study.

BACKGROUND: Vitamin D deficiency (VDD) is recognized as a global pandemic. Identification, any association between VDD and subjective health complaints (SHC), can be helpful to realize critical mechanisms and improve psychological and somatic symptoms. Given few studies published on this issue and the importance of its clarification, the main objective of this study was to examine the association between VDD and the SHC in children and adolescents. METHODS: In this national cross-sectional study, 2596 Iranian children and adolescents aged 8-18 years were included. Data on SHC, anthropometric indices, physical activity, and serum levels of vitamin D were collected. Logistic regression models (crude, adjusted) were applied to examine the association between the VDD and the SHC. Statistical analysis was performed using STATA version 11. P-values< 0.05 were considered as statistically significant. RESULTS: Serum levels of vitamin D in approximately 70% of Iranian children and adolescents were lower than 30 ng/mL. Among the SHC, irritability (40.9%) and feeling anxiety (33.7%) were the most prevalent ones. Multiple complaints in students with the VDD was 2.5 times greater than those with sufficient vitamin D concentrations (p <  0.001). Compared to the reference group, the strongest association was found between vitamin D status and difficulties in getting to sleep (OR: 2.5, 95%CI: 1.18, 3.53, p <  0.001). CONCLUSION: VDD was observed in the considerable percentage of the study population. There were no significant differences between the two gender groups. In addition, there were significant associations between vitamin D status and most of the somatic and psychological symptoms, particularly for getting to sleep. It seems national interventional programs for vitamin D supplementation or food fortifications can be helpful.

Is frequency of potato and white rice consumption associated with cardiometabolic risk factors in children and adolescents: the CASPIAN-V study.

BACKGROUND: This study evaluated the association of frequency of potato and rice consumption with cardiometabolic risk factors in children and adolescents. METHODS: This nationwide cross-sectional survey was conducted on 14,400 children and adolescents. Fasting blood was obtained from a sub-sample of 4200 randomly selected students. Physical examination and laboratory tests were conducted under standard protocols. Metabolic Syndrome (Mets) was defined based on the Adult Treatment Panel III criteria modified for the pediatric age group. The self-reported frequency consumption of white rice and potato was reported on a daily or non-daily basis. RESULTS: The participation rate for the whole study and for blood sampling were 99 and 91.5%, respectively. Overall, 49.4% of the participants were girls while 50.6% were boys. The frequency of daily consumption of white rice and potato was 84.4 and 21.3%, respectively. In the multivariable linear regression model, daily consumption of potato increased body mass index (ß: 0.05, SE: 0.20, p = 0.010), waist (ß: 0.63, SE: 0.24, p = 0.008), and hip circumferences (ß: 0.62, SE: 0.26, p = 0.019). Moreover, in the multivariable logistic regression, daily consumption of potato was significantly associated with an increased risk of overweight (OR: 1.21, 95% CI: 1.04-1.39, P = 0.012). The potato and rice consumption had no statistically significant association with other cardiometabolic risk factors. CONCLUSIONS: Daily consumption of potato was significantly associated with higher anthropometric measures, whereas rice consumption had no statistically significant association with cardiometabolic risk factors. Future research to examine the possible obesogenic effects of intake of potato on children and adolescents is recommended.

Determinants of taking dietary supplements in Iranian children and adolescents: the CASPIAN-V study.

AIM: Tendency for taking dietary supplements is dramatically increasing. However, limited studies exist in this regard. We aimed to assess the frequency and determinants of dietary supplement use among a nationally-representative sample of Iranian children and adolescents. METHODS: This population-based cross-sectional study (the CASPIAN V) was conducted in students aged 7 to 18 years old in 2015. Multistage, stratified cluster sampling method was used to select participants from thirty provinces in Iran. Data regarding taking vitamin and mineral supplements were collected. Demographic information, anthropometric indices, physical activity, screen time and body image were also evaluated. Multivariate logistic regression model was used for analyses. RESULTS: The prevalence of dietary supplements use was 34.1% and the most popular dietary supplement was Iron (12.9%). Multivariate logistic regression showed that boys (0.84, 95%CI: 0.78, 0.91) and body image perception (OR: 0.84, 95%CI: 0.75, 0.94) used less dietary supplements compared to others. Children aged 11 to 14 years (OR: 1.15, 95%CI: 1.06, 1.26) and those with moderate family socioeconomic status (OR: 1.12, 95%CI: 1.007, 1.25) used more supplement compared to other groups. Moreover, those with higher paternal educational level (OR: 0.77, 95%CI: 0.64, 0.93) used less supplements. However, living area, family size, paternal occupation, children BMI, Intended weight loss, and body image by student did not indicate any significant association. CONCLUSION: Our findings indicated that about one-third of Iranian children and adolescents used dietary supplements; iron supplements were the most frequent ones. Children aged 11 to 14 years, those with higher educated mothers and moderate family socioeconomic status used more supplements compared to others. However, boys, children with excess weight and those with high-educated parents used less supplements compared to others. More studies are needed to clarify the efficacy and safety of dietary supplements in different age groups in various societies.

The relationship of serum vitamin D and Zinc in a nationally representative sample of Iranian children and adolescents: The CASPIAN-III study.

Background: Vitamin D (VitD) deficiency is a common worldwide problem. Some previous studies have shown that both Zinc (Zn) and VitD deficiency are prevalent in Iran. This study aimed to assess the relationship of serum Zn and vitamin D levels in a nationally representative sample of Iranian children and adolescents. Methods: This case-control study was conducted as a sub-study of a school-based surveillance program entitled "the CASPIAN-III Study". An equal number of individuals with and without hypovitaminosis D including 330 participants aged 10 to 18 years were selected. The correlation of serum 25 hydroxy vitamin D (25(OH) D), cardiometabolic factors and Zn concentrations was determined. Statistical analysis was done using one-way analysis of variance (ANOVA), Pearson's correlation, linear regression, and logistic regression. Results: The mean age was not significantly different in participants with and without hypovitaminosis D (14.74±2.52 vs. 14.74±2.66 years, respectively, p>0.05). The mean 25(OH) D level was 6.34±1.47ng/ml in the group with hypovitaminosis D and 39.27±6.42ng/ml in controls. The mean Zn level was significantly lower in the hypovitaminosis D group than in controls (1.15±0.26 vs. 1.43±0.32µg/ml, respectively, p<0.001). The Pearson's analysis showed a positive and significant correlation between Zn and 25(OH) D serum levels (p<0.0001). Odds ratios analysis for VitD level between various quartiles of serum zinc concentration for all participants showed that the odds of higher levels of VitD increased by higher levels of Zn. Conclusion: We found significant associations between low serum concentrations of zinc and 25(OH) D. Food fortification or mineral supplementation should be considered in future health programs.

Vitamin D insufficiency among children and adolescents living in Tehran, Iran.

Vitamin D is important for calcium absorption and skeletal growth. Vitamin D insufficiency (VDI) is a prevalent health problem in children. A study was performed to determine the prevalence of VDI in healthy children living in Tehran, Iran. In a cross-sectional study, 963 students (424 boys and 539 girls) aged 7-18 years were selected by random sampling. Serum 25-hydroxyvitamin D (25-OHD), calcium, alkaline phosphatase and phosphorus were measured. VDI was defined as serum 25-OHD <20 ng/ml. Prevalence of VDI was 53.6% in girls and 11.3% in boys. VDI in female students was about five times more common than males (p < 0.000001). VDI in children and adolescent girls is a health problem not only for these age-groups but also for the next generation to come. Encouraging girls to have more sun exposure, fortification of foods and prescription of supplemental vitamin D are recommended.