Aranza Lilián Perea Caballero1, Gloria Elena López Navarrete2, Arturo Perea Martínez2, Mariana Hernández Loera-Chávez1, Ariadna Guadalupe Lara Campos2

1Intercontinental University, Mexico, Mexico
2National Institute of Paediatrics, Mexico, Mexico

Objectives and Study:

Vitamin D (VD) insufficiency is a widespread epidemic linked to different non-
musculoskeletal health outcomes such as immune disorders, cancer and metabolic syndrome.

Supplementation guidelines and official consensus has not been made with exact therapy dosage and diagnosis criteria. Risk factors linked to VD insufficiency are race, obesity, sunscreen and age (the elderly and children). In obesity, deficiency mechanisms proposed are adipose tissue sequestration and volumetric dilution. Volumetric dilution includes total body weight as a primary variable in the development of this disorder and not just body fat, thus defining total body weight as a factor when deciding supplementation therapy. A single blind longitudinal study regarding volumetric dilution proposed a regression based equation to estimate VD doses in order to achieve sufficiency levels in obese adults. The aim of this study was to apply the same mathematical equation to estimate the VD supplementation therapy in a paediatric and adolescent obese population with VD insufficiency/deficiency.

Methods:

Longitudinal randomized control study of 2 different doses of oral vitamin D3 , 800 IU (control group) or mathematical model calculation (intervention group), prescribed daily for 8 weeks during spring-summer of 2017. The subjects were 15 children aged 6 to 18 years with BMI z-score >1.0 recluted among the Obesity and Adolescence Clinic in the National Institute of Paediatrics, Mexico City. All participants and their families signed an informed consent form. Subjects were excluded if they had any chronic condition or if they were taking medications affecting VD metabolism. 25-hydroxycholecalciferol (25(OH) D) was measured at baseline and 8 weeks after supplementation.
Vitamin D deficiency was defined as serum 25(OH)D ≤20 ng/ml and insufficiency as 21-29 ng/ml respectively.

Results:

From total sample insufficiency was found in 7/15 (46.6%) subjects and deficiency occurred in 8/15 (53.3%). 7 subjects were assigned to control group and 8 subjects to the intervention group.
Mean 25(OH)D was 22.81 ng/ml and 18.55 ng/ml for the control and intervention group respectively.
Insufficiency occurred in 4/7 and 3/8 subjects and deficiency was found in 3/7 and 5/8 in the control and intervention group respectively. After intervention, the control group raised an average of 2 ng/ml serum 25 OH D and intervention group raised 6 ng/ ml; however, Fisher ́s exact test was performed and no significant difference was found between both groups. There was no statistical significant difference regarding BMI, body fat percent or waist to height ratio. Deficiency remained only in 1/15 (6.6%) subject from total sample.

Conclusion:

The application of a mathematical estimation model showed better supplementation outcomes compared to standard dose (800 UI) group, however; no significant difference was found.
Different factors influence these results such as environmental factors (season, compliance and sunlight exposure) and a longer follow-up with a bigger population may show different results. Studies with VD supplementation in obese children should continue in order to include its therapy as complementary treatment for this high-risk population.