Naji Aljohani

Vitamin D: Deficiency, Sufficiency and Toxicity

The plethora of vitamin D studies over the recent years highlight the pleomorphic effects of vitamin D outside its conventional role in calcium and bone homeostasis. Vitamin D deficiency, though common and known, still faces several challenges among the medical community in terms of proper diagnosis and correction. In this review, the different levels of vitamin D and its clinical implications are highlighted. Recommendations and consensuses for the appropriate dose and duration for each vitamin D status are also emphasized.

Vitamin D Deficiency and Cardiometabolic Risks: A Juxtaposition of Arab Adolescents and Adults

The recent exponential surge in vitamin D research reflects the global epidemic of vitamin D deficiency and its potential impact on several chronic diseases in both children and adults. Several subpopulations, including Arab adolescent boys and girls, remain understudied. This study aims to fill this gap. A total of 2225 apparently healthy Saudi adolescents (1187 boys and 1038 girls, aged 13-17 years old) and 830 adults (368 men and 462 women, aged 18-50 years old) were respectively recruited from different public schools and medical practices within Riyadh, Saudi Arabia. Anthropometrics were taken and fasting blood samples withdrawn to examine serum glucose and lipid profile by routine analysis and 25-hydroxyvitamin D by ELISA. Almost half of the girls (47.0%) had vitamin D deficiency as compared to only 19.4% of the boys (p<0.001), 36.8% of the adult women and 17.7% of the adult men (p<0.001). Furthermore, in boys there were more significant inverse associations between serum 25(OH)vitamin D levels and cardiometabolic indices than girls, while in contrast women had more significant associations than men. Vitamin D deficiency was significantly associated with diabetes mellitus type 2 (DMT2) [OR 3.47 (CI1.26-5.55); p<0.05] and pre-DM [OR 2.47 (CI 1.48-4.12); p<0.01] in boys. Furthermore, vitamin D insufficiency was significantly associated with abdominal obesity in boys [OR 2.75 (CI 1.1-7.1); p<0.05]. These associations for DMT2 and abdominal obesity were not observed in adult males, girls and adult women. Vitamin D deficiency/insufficiency and hyperglycemia is high among Arab adolescents. Vitamin D deficiency is mostly associated with cardiometabolic risk factors in adolescent Arab boys. This indicates a sex- and age-related disadvantage for boys with low vitamin D status and challenges the extra-skeletal protection of vitamin D correction in adolescent females.

Metabolic syndrome: Risk factors among adults in Kingdom of Saudi Arabia

Background: Metabolic syndrome (MetS) is a cluster of established cardiovascular risk factors that collectively increase predisposition to major chronic diseases, including heart diseases and diabetes mellitus. Citizens of developing countries such as Saudi Arabia are at risk for MetS as a result of industrialization and accessibility to fast foods. In this epidemiologic study, the kingdom-wide prevalence of MetS is determined. Materials and Methods: A total of 4578 Saudis aged 15-64 was randomly selected from 20 regions in Saudi Arabia. Anthropometrics were collected, and fasting blood samples collected to ascertain fasting blood glucose and lipid profile. Components of full MetS as defined by the International Diabetes Federation were used for screening. Results: The overall prevalence of MetS is 28.3%. Prevalence was significantly higher in males than in females (31.4 vs. 25.2%; P = 0.001). Prevalence of MetS was the highest in the northern and central region, and showed a parallel increase with age, and inversely with educational status. Region was also a significant contributor to MetS. Conclusion: Despite accumulating evidence of an epidemic, MetS remains largely unresolved in the kingdom. Aggressive public campaign should be launched, and policies implemented to control any future damage of MetS in the kingdom.

Vitamin D: Light side and best time of sunshine in Riyadh, Saudi Arabia.

Low levels of 25-hydroxyvitamin D have been documented among inhabitants of the wider Middle East and North African countries. Sunlight has long been recognized as a major provider of vitamin D. In this study we aimed to determine the optimum time for sun exposure in the Central region of Riyadh, Saudi Arabia. Ampoules containing 7-dehydrocholesterol in ethanol were exposed to sunlight every hour starting from sunrise until sunset in July and December. Our results demonstrated that the time of the day has a major influence in vitamin D production. In this study, summer production of previtamin D3 was observed to occur between 8:00 PM to 4:00 PM with peak hours between 10:00 AM to 12:00 PM. During wintertime however, the conversion began later at around 9:30 AM and ended sooner at 2:00 PM, with peak hours at 10:00 AM to 12 noon. In conclusion, the optimum time to get sun exposure for vitamin D3 production in Riyadh, during summer is from 9:00 AM and before 10:30 AM, as well as after 2:00 PM until 3:00 PM, while during winter it’s from 10:00 AM until 2:00 PM. These times are important on a public health perspective, as it’s free, relatively safe and the most enjoyable. This strategy is a highly efficacious way for improving the vitamin D status for children and adults and preventing vitamin D deficiency.

Vitamin D status correction in Saudi Arabia: an experts’ consensus under the auspices of the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis, and Musculoskeletal Diseases (ESCEO)

BackgroundVitamin D deficiency is common in the Middle East and in Saudi Arabia, in particular. While several international recommendations on the management of vitamin D deficiency have been documented and practiced globally, these recommendations should be adapted to the conditions of the Middle Eastern region. To address this challenge, the Prince Mutaib Chair for Biomarkers of Osteoporosis (PMCO) in King Saud University (KSU), Riyadh, KSA, together with local experts and in cooperation with the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO), organized a panel that formulated unified recommendations in the diagnosis and treatment of vitamin D deficiency in the region.MethodsThe selection of local and international experts commenced during the 2nd International Vitamin D Symposium conducted in Riyadh, Saudi Arabia, last January 20-–21, 2016. Reviews of the most recent literature were done, and face-to-face meetings were conducted for revisions and final recommendations.Results: Vitamin D sufficiency is defined as circulating serum 25(OH)D ≥50 nmol (≥20 ng/ml) for the general population and vitamin D adequacy as serum 25(OH)D >75 nmol/L l (>30 ng/ml) for the frail and osteoporotic elderly. Despite overwhelming prevalence of vitamin D deficiency, universal screening is not recommended. Recommendations for the general population, children, pregnant/lactating women, post-menopausal women, the elderly, and those with subsequent metabolic diseases were provided.ResultsVitamin D sufficiency is defined as circulating serum 25(OH)D ≥50 nmol (≥20 ng/ml) for the general population and vitamin D adequacy as serum 25(OH)D >75 nmol/L l (>30 ng/ml) for the frail and osteoporotic elderly. Despite overwhelming prevalence of vitamin D deficiency, universal screening is not recommended. Recommendations for the general population, children, pregnant/lactating women, post-menopausal women, the elderly, and those with subsequent metabolic diseases were provided.ConclusionVitamin D supplementation/correction is advised in all persons whose serum 25(OH)D falls below 50 nmol/l (20 ng/ml), and achieving a target of 75 nmol/l (30 ng/ml) is particularly suited for frail, osteoporotic, and older patients. Conducting well-designed clinical trials in the region that will address economic implications and investigations on the treatment persistence and compliance to vitamin D treatment in the region are encouraged.

Morbidity and pregnancy outcomes associated with sickle cell anemia among Saudi women

To identify morbidity and pregnancy outcomes associated with sickle cell disease (SCD) among pregnant Saudi women.

Managing Prolactinomas during Pregnancy.

Prolactinomas are the most prevalent functional benign pituitary tumors due to a pituitary micro- or macroadenoma. The majority of patients presents with infertility and gonadal dysfunction. A dopamine agonist (DA) (bromocriptine or cabergoline) is the treatment of choice that can normalize prolactin levels, reduce tumor size, and restore ovulation and fertility. Cabergoline generally preferred over bromocriptine because of its higher efficacy and tolerability. Managing prolactinomas during pregnancy may be challenging. During pregnancy, the pituitary gland undergoes global hyperplasia due to a progressive increase in serum estrogens level that may lead to increase of the tumor volume with potential mass effect and visual loss. The risk of tumor enlargement may occur in 3% of those with microadenomas, 32% in those with macroadenomas that were not previously operated on, and 4.8% of those with macroadenomas with prior ablative treatment. Though both drugs appear to be safe during pregnancy, the data on fetal exposure to DAs during pregnancy have been reported with bromocriptine far exceeds that of cabergoline with no association of increased risk of pregnancy loss and premature delivery. It is advisable to stop the use of DAs immediately once pregnancy is confirmed, except in the case of women with invasive macroprolactinomas or pressure symptoms. This review outlines the therapeutic approach to prolactinoma during pregnancy, with emphasis on the safety of available DA therapy.

Sun exposure, skin color and vitamin D status in Arab children and adults

Accumulating evidence suggests an increased prevalence of vitamin D deficiency in the Middle East and North African countries. Sunlight has long been recognized as a major provider of vitamin D and lighter skin color has been associated with better vitamin D status. In this context, we aimed to determine whether 25-hydroxyvitamin D[25-(OH)D] concentrations are related to skin color, sun exposure and gender among healthy Saudi children and adults. A total of 808 Saudi children (age=14.6±0.04years) and 561 (age=31.4±0.3years) adults of both genders were included in this study. Levels of sun exposure and skin color were determined using a standard questionnaire. Anthropometry and plasma 25-(OH)D concentrations were analyzed. On the basis of duration of sun exposure (<20min vs. >20min), a significantly lower concentration of 25-(OH)D (40.9±1.2 vs. 35.5±1.8nmol/l; p<0.019) was demonstrated in dark-skinned boys with exposure time less than 20min than those exposed longer than 20min. We were unable to show an effect of sunlight exposure or skin color on vitamin D status of children or adults, except in dark-skinned boys who had lower 25(OH)D concentrations associated with limited sun exposure.

Vitamin D deficiency among subfertile women: case-control study.

Abstract Objective: The objective of the study is to compare the dietary vitamin D and calcium intake among subfertile women (cases) versus pregnant women (controls) and to determine the vitamin D levels in the subfertile and pregnant women. The study design was an observational case-control study where a total of 181 (83 previously diagnosed subfertile cases from various causes and 98 pregnant controls) women of reproductive age. A validated questionnaire was used where it focused on key indicators evaluating vitamin D-related factors. Blood was withdrawn for the measurement of serum calcium, albumin and phosphate to exclude secondary causes that might affect vitamin D level. Results: The prevalence of vitamin D deficiency was significantly higher in the subfertile group than controls (59.0% versus 40.4%; p < 0.01). Calcium supplements intake was significantly higher in controls than the subfertile group (64.6% versus 10.0%; p value < 0.001). Total dietary vitamin D intake (> 400 IU/day) was significantly higher in the controls than the subfertile group. Conclusion: Vitamin D deficiency is prevalent among subfertile women. Optimization of serum calcium and vitamin D levels is encouraged.

Differences and associations of metabolic and vitamin D status among patients with and without sub-clinical hypothyroid dysfunction

BackgroundSub-clinical hypothyroid dysfunction, a relatively understudied disorder in the Kingdom of Saudi Arabia (KSA), has significant clinical implications if not properly monitored. Also from KSA, more than 50% of the population suffer from hypovitaminosis D (<50 nmol/l). In this cross-sectional case-control study, we described the differences and associations in the metabolic patterns of adult Saudis with and without hypothyroid dysfunction in relation to their vitamin D status, PTH, calcium and lipid profile.MethodsA total of 94 consenting adult Saudis [52 controls (without subclinical hypothyroidism), 42 cases (previously diagnosed subjects)] were included in this cross-sectional study. Anthropometrics were obtained and fasting blood samples were taken for ascertaining lipid and thyroid profile, as well as measuring PTH, 25(OH) vitamin D and calcium.ResultsCases had a significantly higher body mass index than the controls (p < 0.001). Circulating triglycerides was also significantly higher in cases than the controls (p = 0.001). A significant positive association between HDL-cholesterol and PTH (R = 0.56; p = 0.001), as well as a negative and modestly significant negative association between LDL-cholesterol and PTH (R = - 20.0; p = 0.04) were observed. FT3 was inversely associated with circulating 25 (OH) vitamin D (R = -0.25; p = 0.01).ConclusionsPatients with hypothyroid dysfunction possess several cardiometabolic risk factors that include obesity and dyslipidemia. The association between PTH and cholesterol levels as well as the inverse association between vitamin D status and FT3 needs to be reassessed prospectively on a larger scale to confirm these findings.