Vitamin D and Zinc are Interlinked But Affected by Different Growth Factors in Iranian Children and Adolescents: Vitamin D and Zinc in Iranian Children and Adolescents

Abstract

Background: Zinc and vitamin D are essential factors required for growth. Recently, studies have shown a possible link between serum zinc and vitamin D levels. Objectives: This study was designed to evaluate this link and its possible affecting growth factors in children and adolescents in Iran. Methods: This cross-sectional study was performed on the data obtained from children aged 2 to 18 years old referring to a growth assessment clinic for routine growth follow-ups in the city of Shiraz from April to August 2019. A total of 454 children who were checked for 25-hydroxyvitamin D and zinc simultaneously were included. Results: Vitamin D was negatively correlated with body mass index (BMI) z-scores, while zinc was positively correlated with vitamin D and height z-scores. Subjects with vitamin D levels ≤ 8.6 ng/mL were 2.081 times more likely to have a zinc deficiency. Vitamin D insufficiency was significantly higher in overweight and obese children. Mean vitamin D and zinc levels were significantly lower, and vitamin D insufficiency was significantly higher in boys than girls. While mean zinc levels were significantly lower in short children, the prevalence of zinc deficiency was not statistically different between short and normal height statures. Conclusions: Very low vitamin D levels are likely to be accompanied by zinc deficiency, possibly caused by malnutrition and the modulatory effect of serum vitamin D on zinc absorption. Unlike zinc deficiency, vitamin D insufficiency is much more prevalent in Iranian children than in children from other countries. Vitamin D and zinc are associated with BMI and height z-scores, respectively.

Overnutrition is a risk factor for iron deficiency in children and young people: a systematic review and meta-analysis of micronutrient deficiencies and the double burden of malnutrition

“…Although a direct relationship between zinc status and undernutrition was concluded by the majority of studies (12 of 20 accounting for 72,537 participants; Figure 4B), the results from reports on overnutrition were more contradictory. While 4 studies concluded direct associations between zinc levels and BMI 42 59-61 , 2 found inverse relationships 62 63 and 6 studies, accounting for 13,440 participants in 4 countries (3 from Iran [64][65][66] , and 1 from Colombia 67 , Australia 68 , and China 69 ), concluded no association between zinc status and overweight (Figure 4B). Among the studies reporting direct associations with both under-and overnutrition was an exceptionally large population study from China with >64,000 participants 42 62 .…”

Overnutrition is a risk factor for iron, but not for zinc or vitamin A deficiency in children and young people: a systematic review and meta-analysis

“…Although a direct relationship between zinc status and undernutrition was concluded by the majority of studies (12 of 20 accounting for 72 537 participants; figure 4B), the results from reports on overnutrition were more contradictory. While four studies concluded direct associations between zinc levels and BMI, 42 61 66 67 two found inverse relationships 68 69 and six studies, accounting for 13 440 participants in four countries (three from Iran, [70][71][72] and one from Colombia, 73 Australia 74 and China 75 ), concluded no association between zinc status and overweight (figure 4B). Among the studies reporting direct associations with both undernutrition and overnutrition was an exceptionally large population study from China with >64 000 participants.…”