Evaluation of vitamin D supplementation intake among children; cross-sectional observational study

Introduction

Vitamin D is known among the critical minerals to play an important role in maintaining normal body functions.¹ It allows bone mineralization and avoids hypocalcemic tetany (such as involuntary muscle contraction, cramps, spasms, etc).² It is also known for aiding osteoblasts and osteoclasts in developing and remodeling the bone preventing it from being brittle.³ Other functions of vitamin D in the body include inflammation reduction and regulation of cell growth, neuromuscular and immune function, and glucose metabolism.⁴ Vitamin D also affects the expression of several genes that code for proteins that govern cell proliferation, differentiation, and apoptosis. Vitamin D receptors can be found in many tissues, and some of them transform 25(OH) D to 1,25 (OH) D.⁵

Maintaining optimum levels of calcium and vitamin D during childhood and adolescence is critical for bone growth.⁶ Vitamin D is said to lower the risk of cancer, prevent viral infections, alleviate musculoskeletal pain, and calm mood disorders including depression, according to some claims. There has also been a surge in scientific interest in studying vitamin D at both the basic and clinical levels to address these and other claims.⁷ Children with vitamin D deficiency develop a disease known as rickets, which is characterized by a frame and fragile bone, making the legs appear bent.⁸ Vitamin D has been shown to reduce the risk of premature birth in pregnant women.⁹

A child's vitamin D deficiency can start as early as birth, which can damage not just their bone metabolism but also their immunological system, making them more susceptible to illnesses early in life.¹⁰ For the treatment of vitamin D deficiency rickets, the American Academy of Pediatrics (AAP) recommends an initial two- to three-month regimen of “high-dose” vitamin D therapy of 1000 units daily in neonates, 1000 to 5000 units daily in infants one to 12 months old, and 5000 units daily in patients over 12 months old.¹¹

Epidemiologic studies, at least in adults, apart from the risk of osteomalacia and osteoporosis, have associated hypovitaminosis D with an increased risk of several cancers, autoimmune diseases (type 1 diabetes, multiple sclerosis, rheumatoid arthritis, and Crohn’s disease), heart disease, hypertension, metabolic syndrome, asthma, upper respiratory tract infections, muscle weakness, and falling.¹² The pleiotropic action of vitamin D was already revealed on molecular, cellular, tissue, and organ levels.¹³ These observations modified the current knowledge about vitamin D metabolism and methods of diagnosis of vitamin D deficiency states.¹⁴

Unfortunately, vitamin D is found rare in food.¹⁵ Vitamin D is found in only a few foods. Fish liver oils and the meat of fatty fish (such as trout, salmon, tuna, and mackerel) are among the greatest sources. The amount of vitamin D in a human's tissue is influenced by its food. Vitamin D is also found in modest levels in beef liver, egg yolks, and cheese, mostly in the form of vitamin D3 and its metabolite 25(OH)D3.¹⁶ Vitamin D2 is found in varying levels in mushrooms. Some commercially available mushrooms have been exposed to UV radiation to boost their vitamin D2 levels. In addition, the FDA has approved UV-treated mushroom powder as a food additive for use as a vitamin D2 source in food items.¹⁷

Furthermore, vitamin D is added to milk, many ready-to-eat bowls of cereal, and some yogurt and orange juice brands. It is found in modest concentrations in cheese and some margarine.¹⁸

In the U.A.E., the consistent predominant hot weather, inadequate exposure to sunlight, and low nutritional intake of vitamin D result in low serum concentrations of circulating 25(OH) D, a condition known as hypovitaminosis D.¹⁹ Furthermore, recent lifestyles involving using cars for transport over walking, and children indulging in electronics and staying indoors have also influenced low vitamin levels. Low dietary intake of vitamin D and calcium, and other factors, including obesity and low social status, are all associated with low serum levels of vitamin D.^20–22

Further research is needed to be conducted on the production of high-potency–food-based vitamin D supplements, the move to mandatory fortification of cereal grain staples, and the development of natural food sources with higher vitamin D content are all potentially safe and efficient pathways for overcoming the barriers to optimal vitamin D status. Although various studies suggest a high prevalence of vitamin D deficiency among adults and children, no randomized controlled trials have been fully performed on vitamin D deficiency and supplementation among children in the UAE. When compared to the expense of providing therapies for many chronic diseases closely linked to vitamin D deficiency, taking vitamin D supplements is a much better alternative.

The purpose of this study was to review the vitamin D supplementation intake status among children in the general public, to evaluate the vitamin D supplements practices, the natural sources of vitamin D from their diet, and the barriers that parents and children face with supplementation.

Methods

Results

The study reported no missing data. A total of 248 parents (89.1% mothers (n=203)) and 15.7% fathers (n=39) with a mean±SD age of 35.4±7.042 years, completed the study. About 62.9% (n=156) parent were holding a university degree, while 26.2% (n=65) of the participants completed a secondary school, 9.7% (n=24) completed primary school and 1.2% (n=3) of parent were uneducated. Moreover, almost 61.7% (n=153) of mothers were unemployed, while a smaller number of mothers 27% (n=67), and 11.3% (n=28) were employed and employed with medical background. For fathers the 70.2% (n=174) were employed and 21% (n=52), 4.8% (n=12) and 4% (n=10) were self-employed, employed with a medical background and unemployed, respectively. Approximately 42.7% (n=106) participants had income level of more than 10,000, while 35.5% (n=88), 10.1 (n=25) and 4.8 (n=12) had income level of 5,000-10,000, 2,000-5,000 and less than 2,000, respectively. More than half of the participants has insurance and only a few participants 28.6% (n=71) had no insurance (Table 1).

Study flow diagram.

This research has participants from different countries (total=23). The majority (67%) of participants are from five countries (India, Iran, Pakistan, Syria, and Emirates). The completed data has been presented in Figure 1.

Figure 1. Nationality distribution of study participants.

A higher proportion of children received supplements whose parents were educated to the level of secondary school and above. Table 2 shows the literacy level of parents and supplementation.

The data on outdoor activity levels included the average frequency of outdoor activity per day. Of all the parents, 65% (162) of them reported sending their child outside to play while 34.67% (86) had no outdoor activity. The mean hours of outdoor activity for the children were 2.046$\pm 1.61.$ It was found that on average, children spent 0.15-6 hours playing outside in the sun therefore exposed to sunlight (Table 3).

Parents reported that supplements used the most by children were Vitamin D supplements (21.85%) and multivitamins (21.8%) followed by calcium supplements (5.6%). However, 27.8% of children in this study did not take any supplements. While other parents reported mixed intake of supplements (for example some children took vitamin D plus calcium supplements while others took vitamin D and multivitamins (Figure 2).

Figure 2. Supplementation intake among the study participants.

Figure 3 summarizes and describes that out of the 248 participants, 184 (74.2%) parents reported their child’s diet to contain multiple natural sources of vitamin D (for example some children had milk plus cheese in their diet while others had yogurt plus cheese plus vitamin D fortified orange juice). However, 69 (27.8%) parents reported giving none of the natural sources of vitamin D to their children through the diet.

Figure 3. Children’s intake of natural sources containing vitamin D.

Children in high-income families (43.63%) were more likely to receive vitamin D supplements than those in middle- or low-income families (Table 4).

Parents with private health insurance 51.85% were more likely to give vitamin D supplements to their children compared to those with government health insurance 25.92% and no health care insurance 22.22% (Table 5).

The study included participants from 23 various nationalities. The top five countries with the most participants were, India, Pakistan, Syria, and the U.A.E. Out of 34 participants from India, only 11 (32.35%) reported the use of vitamin D supplementation by their children, four (11.76%) reported using calcium supplements, six (17.64%) reported using multivitamins and the other 6 of them (17.64%) reported giving multiple sources of vitamins to their children.

However, out of the 34 participants from India, seven (20.58%) did not use any vitamin supplements at all. While out of 28 participants from Iran, only 6 participants, (21.41%) reported the use of vitamin D supplementation by their children, three (10.71%) reported using calcium supplements, ten (35.71%) reported using multivitamins and the other eight of them (28.57%) reported giving multi-sources of vitamins to their children. Among the 34 participants from Pakistan, the lowest amount of vitamin D supplements intake, only four (11.76%) participants reported giving supplements to their children and three (8.82%) reported using calcium supplements, only one (2.94%) parent reported using multivitamins and the other 12 of them (34.29%) reported giving multi-sources of vitamins to their children. Out of 27 participants from Emirates, few participants which are five (18.51%) of them reported the use of vitamin D supplementation by their children, two (7.4%) reported using calcium supplements, seven (25.94%) reported using multivitamins and the rest 11 (40.74%) reported giving multi-sources of vitamins to their children. The participants from Syria reported the highest vitamin D intake among the countries, out of 40 participants from India, only 12 (30.76%) reported the use of vitamin D supplementation by their children, one (2.56%) reported using calcium supplements, nine (23.07%) reported using multivitamins and the other 10 (25.64%) reported giving multiple sources of vitamins to their children Table 6.

Discussion

This cross-sectional study demonstrates that inadequacy of vitamin D remains a risk in the U.A.E due to its geographical location being at the equator leading to the hot harsh climate throughout the year limiting the children’s exposure to sunlight. Depending on the effectiveness of UVB photons to promote vitamin D production, the amount of sun exposure necessary for the creation of ultraviolet B-induced vitamin D in the skin impacts cutaneous synthesis.²⁵ This study also identifies the association between socioeconomic and demographic barriers with vitamin D supplementation among children. Children in high-income families (43.63%) were more likely to take vitamin D supplements than those in middle- or low-income families.

Parents with private health insurance (51.85%) were more likely to provide vitamin D supplements to their children compared to those with government health insurance (25.92%) and no health insurance (22.22%).

Furthermore, it was found in this study that parents’ education and literacy level largely determines children receiving vitamin D supplementation. Parents in this study with a lower literacy rate who did not complete primary school were less likely to give vitamin D supplements to their children. However, evidence of gender differentials in vitamin D supplementation was not found in this study.

In U.A.E., since there is no law requiring the fortification of vital foods with vitamin D, there are few vitamin D-fortified products on the market.²⁶ Among the participants of the study, 184 (74.2%) reported the child’s diet to contain multiple natural sources of vitamin D (for example some children had milk plus cheese in their diet while others had yogurt plus cheese plus vitamin D fortified orange juice) and most parents reported that their child has milk in their diet. Moreover, 69 parents (27.8%) reported giving none of the natural sources of vitamin D to their children through the diet. As a result, individual vitamin D dietary intake is strongly influenced by dietary preferences as well as the country's fortification plan. Without supplementation, however, vitamin D status is heavily on endogenous vitamin D synthesis, which is influenced by genetic determinants and lifestyle.²⁷

Vitamin D aids calcium absorption in the intestine by facilitating active calcium transport across the mucosa. Vitamin D insufficiency is usually caused by a lack of calcium in the diet and leads to bone deterioration or osteoporosis.²⁸ The results of this study are generalizable since it has been done on general population and multiple ethnicities in the U.A.E, it reflects that this study is generalizable to different parts of the world.

Conclusion

The findings of the study concluded that the educational and financial background of parents and health insurance status could aid in addressing the challenges parents face with providing vitamin D supplements to their children as well as nutritional assessment for early natural supplement treatment.