Complications of vitamin d deficiency

Vitamin D

Vitamin D is a fat-soluble vitamin, naturally present in some foods. It has several roles in the body. It promotes calcium and phosphorus absorption in the gut and maintains their normal blood level. Vitamin D also inhibits the release of parathyroid hormone which is responsible for bone resorption. It is believed that vitamin D improves muscles and the immune system and prevents osteoporosis, cancer, high blood pressure, and several autoimmune diseases.

Vitamin D can be obtained from exposure to sunlight which contributes production of the vitamin under the skin. The proper amount of vitamin D and the required length of sunbathing depends on the person’s age, the color of the skin, and present medical condition.

Older people produce less vitamin D due to their thinner skin. People with pigmented skin have to spend more time exposed to the sun, particularly in winter.

Vitamin D can be found, in small amounts, in food. Types of food rich in vitamin D are oily fish (herring, tuna, salmon, etc.), mushrooms, egg yolk, liver, cheese, milk, and butter. Vitamin D is added to margarine, cereals, and instant milk. In the US, commercially fortified cow’s milk contains around 100 units of vitamin D per 8 ounces, which makes it the richest source of vitamin D.

Vitamin D Deficiency

Vitamin D deficiency can occur due to several reasons:

(1) Insufficient vitamin D intake combined with insufficient exposure to the sun.

(2) Failure to absorb vitamin D from the gut.

(3) Inability to synthesize vitamin D because of kidney or liver conditions.

Infants are at risk of vitamin D deficiency because breast milk as well as infant milk formulas don’t contain enough vitamin D. Elderly people usually don’t eat foods rich in vitamin D and their vitamin D absorption can be restricted.

Inadequate sun exposure can be seen in infants and children since their parents often protect them from the harmful effect of the sun. Also, people with darker skin and those living in northern parts of the world often experience vitamin D deficiency because of this reason.

Vitamin D deficiency causes the bone hypomineralization disorder osteomalacia in humans and is associated with many non-skeletal disorders. We aim to estimate the global and regional prevalence of vitamin D deficiency in people aged 1 year or older from 2000 to 2022.

We systematically searched Web of Science, PubMed (MEDLINE), Embase, Scopus, and Google databases on December 31, 2021, and updated them on August 20, 2022, without language and time restrictions. Meanwhile, we identified references of relevant system reviews and eligible articles and included the latest and unpublished data from the National Health and Nutrition Examination Survey (NHANES, 2015–2016 and 2017–2018) database.
The studies investigating the prevalence of vitamin D deficiency in population-based studies were included. A standardized data extraction form was used to collect information from eligible studies. We used a random-effects meta-analysis to estimate the global and regional prevalence of vitamin D deficiency. We stratified meta-analyses by latitude, season, six WHO regions, the World Bank income groups, gender, and age groups.
Out of 67,340 records searched, 308 studies with 7,947,359 participants from 81 countries were eligible for this study, 202 (7,634,261 participants), 284 (1,475,339 participants), and 165 (561,978 participants) studies for the prevalence of serum 25(OH)D
We found that globally, 15.7% (95% CrI 13.7–17.8), 47.9% (95% CrI 44.9–50.9), and 76·6% (95% CrI 74.0–79.1) of participants had serum 25-hydroxyvitamin D levels less than 30, 50, and 75 nmol/l, respectively; the prevalence slightly decreased from 2000–2010 to 2011–2022, but it was still at a high level; people living in high latitude areas had a higher prevalence; the prevalence in winter-spring was 1.7 (95% CrI 1.4–2.0) times that in summer-autumn; the Eastern Mediterranean region and Lower-middle-income countries had a higher prevalence; females were vulnerable to vitamin D deficiency; gender, sampling frame, detection assays, sampling region, time of data collection, season, and other factors contributed to heterogeneity between the included studies.

✓ Fact confirmed: Global and regional prevalence of vitamin D deficiency in population-based studies from 2000 to 2022: A pooled analysis of 7.9 million participants Aiyong Cui1, Tiansong Zhang, Peilong Xiao, Zhiqiang Fan, Hu Wang and Yan Zhuang; 17 March 2023

Some diseases like celiac disease, Crohn’s disease, and cystic fibrosis, impair the body’s ability to absorb enough vitamin D. This function of the body can also be affected by surgery that removes part of the stomach or intestines, such as gastric bypass.

Kidneys and liver contain enzymes that transform vitamin D from the sun and food to biologically active vitamin D. Those who are suffering from kidney or liver disease may also suffer from vitamin D deficiency due to the lack of mentioned enzymes. This also applies to familial diseases that damage liver or kidney enzymes responsible for the production of biologically active vitamin D.

Complications

Deficiency in vitamin D can result in many conditions and disorders. Symptoms of depression may increase because of a lack of vitamin D. People with multiple sclerosis may experience complications for the same reason. They need to take additional vitamin D to prevent relapses. Sufficient vitamin D intake may aid in preventing multiple sclerosis as well.

Vitamin D enhances the immune system. Thereby, people with vitamin D deficiency become prone to infections and illnesses.