Vitamin D in Saudi Arabia: Prevalence,distribution and disease associations

Vitamin D and orthodontics: an insight review

Vitamin D is known as the oldest of all hormones. 7-Dehydrocholesterol is converted to previtamin D₃. It becomes a secosteroid when it is later converted to 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃). A number of factors influence vitamin D₃ production, including skin pigmentation, the use of sunscreen lotions, season, latitude, and altitude. Vitamin D is important for bone metabolism and calcium hemostasis. Researchers have linked a deficiency in vitamin D levels to a number of systemic complications, including cardiovascular disease, diabetes, immune deficiency, and infectious diseases. In orthodontics, laboratory studies have revealed some evidence that vitamin D enhances tooth movement and the stability of the tooth position. This review is an attempt to understand the role and systemic consequences of vitamin D deficiency and to examine its relevance to orthodontics.

Lower vitamin D levels in Saudi pregnant women are associated with higher risk of developing GDM

BACKGROUND

Gestational diabetes mellitus (GDM) has serious consequences such as increased risks of preeclampsia, macrosomia and cesarean delivery. Even though the mechanistic basis of GDM has not been completely understood, several risk factors have been identified and one of these is vitamin D. However, the link between vitamin D deficiency and development of GDM is yet to be proven with certainty.

METHODS

This study aimed to investigate the link between the incidence of GDM and serum vitamin D level in pregnant women of Saudi Arabia. 515 Saudi women (ages 18-46) in their 24-28th week of pregnancy, visiting various hospitals of Riyadh, participated in this study. Serum vitamin D and various biochemical and anthropometric parameters were determined in the first trimester and the recruits were screened for GDM by OGTT according to IADPSG criteria in their 2nd trimester. The association between vitamin D deficiency and development of GDM was calculated based on odds ratio of the incidence of GDM among vitamin D deficient and normal women.

RESULTS

In this study cohort of 515 pregnant women, in the first trimester vitamin D deficiency (< 50 nmol/l) was detected in 425 (82.5%). On their 2nd visit (2nd trimester), 116 (27.7%) were diagnosed with GDM out of 419 with OGTT, according to IADPSG criteria. GDM risk was significantly higher among vitamin D deficient than non-deficient women (Odds Ratio: 2.87; Confidence Interval: 1.32-6.25; P = 0.008) even after adjusting for season, sun exposure and vitamin D intake (OR: 2.9; CI: 1.07-7.89). Of the various anthropometric and biochemical parameters, the GDM women differed significantly from non-GDM women with respect to serum levels of triglycerides (in mmol/l) (1.3 ± 0.6; 1.5 ± 0.6, p = 0.018) and fasting glucose (in mmol/l) [4.7 (4.3-5.2); 5.1 (4.6-5.6), p < 0.01]. Also, fasting glucose level in the 2nd trimester correlated inversely to serum vitamin D level determined during the 1st trimester (r = - 0.121; p = 0.014).

CONCLUSIONS

Results of our study reveal a significantly higher risk of development of GDM among pregnant women having deficient vitamin D status.

The Prevalence of Hypovitaminosis D and Its Associated Risk Factors Among Women of Reproductive Age in Saudi Arabia: A Systematic Review and Meta-Analysis

Vitamin D deficiency is currently a worldwide epidemic. Middle Eastern countries, including Saudi Arabia, have high vitamin D deficiency prevalence, most prominently among women, despite their plentiful year-round sunshine. Previous research investigating vitamin D status among Saudi women of reproductive age (15-49 years) is scarce, and no study has used a nationally representative sample, so this review quantified overall hypovitaminosis D prevalence among women in Saudi Arabia and explored the associated risk factors. The Web of Science, Scopus, and Medline databases were searched for prior studies in Saudi Arabia exploring vitamin D status among women of reproductive age, published between January 1, 2000 and May 25, 2017. Data were extracted from the identified studies, and a random effects model meta-analysis established the overall hypovitaminosis D prevalence. The initial search yielded 223 possibly relevant articles; 13 were confirmed as eligible, with samples totaling 2877 women aged between 15 and 49 years. Meta-analysis revealed a mean serum 25-hydroxyvitamin D, 25(OH)D, level of 13.1 ng/mL (95% confidence interval [CI]: 11.6-14.6) and an overall prevalence of hypovitaminosis D, defined as 25(OH)D < 30 ng/mL, of 77.4% (95% CI: 63.2-87.3), mostly due to insufficient sunlight exposure and low dietary vitamin D intake. There is therefore a need for a national strategy to raise vitamin D levels among women in Saudi Arabia by advising them on natural vitamin D sources, and recommending the timing and duration of sun exposure, while also defining a national approach to vitamin D fortification and supplementation.

Vitamin D status in irritable bowel syndrome and the impact of supplementation on symptoms: what do we know and what do we need to know?

BACKGROUND

Low vitamin D status is associated with risk of colorectal cancer and has been implicated in inflammatory bowel disease. Irritable bowel syndrome (IBS) is a chronic, relapsing, functional bowel disorder. A nascent literature suggests a role for vitamin D in IBS, but this has not been collated or critiqued. To date, seven studies have been published: four observational studies and three randomised controlled trials (RCTs). All observational studies reported that a substantial proportion of the IBS population was vitamin D deficient. Two intervention studies reported improvement in IBS symptom severity scores and quality of life (QoL) with vitamin D supplementation. There are limited data around the role of vitamin D in IBS.

CONCLUSIONS

The available evidence suggests that low vitamin D status is common among the IBS population and merits assessment and rectification for general health reasons alone. An inverse correlation between serum vitamin D and IBS symptom severity is suggested and vitamin D interventions may benefit symptoms. However, the available RCTs do not provide strong, generalisable evidence; larger and adequately powered interventions are needed to establish a case for therapeutic application of vitamin D in IBS.

Assessment of gender-related differences in vitamin D levels and cardiovascular risk factors in Saudi patients with type 2 diabetes mellitus

Diabetes is a major risk factor for cardiovascular disease (CVD) including stroke, coronary heart disease, and peripheral artery disease. It remains a leading cause of mortality throughout the world, affecting both women and men. This investigation was aimed to study gender based differences in cardiovascular risk factors of adult population with type-2 diabetes mellitus (T2DM) and to check the correlation between serum HbA1C, lipid profile and serum vitamin D levels, in T2DM patients of Riyadh, Saudi Arabia. This hospital-based cross-sectional study involving subjects was divided into two gender based groups; normal male (800), diabetic male (800) and normal female (800) and T2DM females (800). Blood samples were analyzed for fasting glucose (FBG), HbA1c, total cholesterol (TC), triglycerides (Tg), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C) and serum levels of 25(OH)-vitamin D in all groups. All the glycemic control parameters and lipid profile parameters were found to be significantly different in diabetic vs non-diabetic group (p < 0.001) in both genders. The results also show that vitamin D concentration decreased significantly (p < 0.001) in diabetic patients than the healthy individuals in both the genders. Vitamin-D and HbA1C were negatively correlated in both males and females in T2DM patients and significant at P < 0.05. Our study reveals that dyslipidemia remains one of the major risk factors of CVD in T2DM. In addition to dyslipidemia, decreased levels of vitamin-D associated with increased HbA1C alarms the early diagnosis of Type 2 Diabetes.

Extremely High Prevalence of Maternal and Neonatal Vitamin D Deficiency in the Arab Population

BACKGROUND

Vitamin D deficiency is a global public health problem. The published literature on vitamin D deficiency is limited among Arab pregnant women and its association with different metabolic markers.

OBJECTIVE

To determine the prevalence of vitamin D deficiency in Arab pregnant women and neonates and its association with various biomarker profiles.

METHODS

This is a multicenter study taken from a large prospective project in Riyadh, the capital city of Saudi Arabia. Maternal biochemical levels were measured routinely. Maternal and neonatal 25(OH)D levels were assessed using a chemiluminescence immunoassay. A total of 1,097 pregnant women >16 years old with gestational ages <24 weeks were recruited from different tertiary hospitals in Riyadh between February 2011 and June 2012.

RESULTS

Almost 85% of pregnant subjects had 25(OH)D level <50 nmol/L. Vitamin D deficiency among neonates was 88%. Maternal 25(OH)D was significantly associated with neonatal 25(OH)D (r = 0.54, p < 0.01), as well as serum calcium (r = 0.16, p = 0.02) and phosphate levels (r = 0.17, p = 0.02), and had an inverse correlation with parathyroid hormone (r = -0.22, p = 0.001).

CONCLUSION

Maternal and neonatal vitamin D deficiency is alarmingly high in Arabs and significantly associated with each another. Universal screening for serum 25(OH)D may be appropriate for Arab mothers and vitamin D supplementation mandatory until term. The study puts a spotlight on vitamin D deficiency with the hope that health professionals will address it adequately to prevent the known long-term consequences for metabolism and bone health of both mothers and their children.