Vitamin D and cardiovascular diseases: A narrative review.

Cardiovascular diseases (CVD) and vitamin D deficiency are becoming highly prevalent among general populations. Despite plausible biological mechanisms for the role of vitamin D in cardio-protection, a cause-and-effect relationship has not yet been established. The interest in vitamin D as a potential therapeutic target to attenuate cardiovascular risk has been raised. The question about the benefit of vitamin D supplementation for cardiovascular outcomes cannot be answered certainly for the moment. The association between hypovitaminosis D and CVD has been proven by some studies while other studies deny any such link. The present narrative review gives a comprehensive overview of studies on the potential impact of hypovitaminosis D on CVD. The potential role of vitamin D supplementation in the management of CVD is also evaluated. Particular emphasis is paid to those studies that achieve a high level of scientific evidence.

Relationship Between Metabolic Syndrome and Polycystic Ovary Syndrome with Special Reference to C-Reactive Protein.

OBJECTIVES: To estimate C-reactive protein (CRP) levels in Saudi women with and without polycystic ovary syndrome (PCOS), and to investigate the associations between CRP and metabolic syndrome (MetS) components. METHODS: We randomly recruited 200 women with and without PCOS, between 18 and 38 years, in this age-matched case-control study. Study subjects were allocated to 1 of 4 groups according to the presence or absence of MetS. Interviews were conducted with all participants, and anthropometric measurements and blood samples were obtained for subsequent analysis of biochemical variables. RESULTS: Two-thirds of the study population and all study subjects had central obesity. Fasting insulin and homeostasis model assessment insulin resistance index were significantly higher in PCOS and MetS groups than all other groups (P < 0.05). CRP levels were significantly higher among women with PCOS than their age-matched controls, regardless of the presence of MetS (P < 0.05). Body mass index was the only independent predictor of serum high-sensitivity-CRP, accounting for 17% of the variability in circulating levels (ß = 0.407; 95% CI 0.248-0.472, P < 0.0001). CONCLUSIONS: Obesity and insulin resistance are important risk factors for MetS in PCOS. The presence of MetS in PCOS subjects aggravates the proinflammatory state reflected by CRP levels.

Directly measured free and total 25-hydroxyvitamin D levels in relation to metabolic health in multi-ethnic postmenopausal females in Saudi Arabia.

BACKGROUND: Measurement of free 25-hydroyvitamin D (25(OH)D) status has been suggested as a more representative marker of vitamin D status than that of total 25(OH)D. Previously, free 25(OH)D could only be calculated indirectly; however, a newly developed direct assay for the measurement of free 25(OH)D is now available. The aim of this study therefore was to investigate directly measured total and free vitamin D levels association with metabolic health in postmenopausal healthy women living in Saudi Arabia. METHODS: A sample of 302 postmenopausal women aged ≥50 years (n = 302) living in Saudi Arabia were recruited in a cross-sectional study design. Blood samples were collected from subjects for measurement of serum levels of total 25(OH)D, directly measured free 25(OH)D, metabolic bone parameters, lipid profile, and other biochemical tests. RESULTS: A positive correlation was found between directly measured free and total 25(OH)D (r = 0.64, P< 0.0001). Total but not free 25(OH)D showed significant association with serum intact parathyroid hormone (P = 0.004), whilst free 25(OH)D but not total 25(OH)D showed a significant association with total cholesterol and LDL-C (P = 0.032 and P = 0.045, respectively). CONCLUSIONS: Free 25(OH)D and total 25(OH)D were found to be consistently correlated but with different associations to metabolic health parameters. Further research is needed to determine which marker of vitamin D status would be the most appropriate in population studies.

Association of SNPs in GC and CYP2R1 with total and directly measured free 25-hydroxyvitamin D in multi-ethnic postmenopausal women in Saudi Arabia.

BACKGROUND: Group-specific component (GC) and cytochrome P450 Family 2 Subfamily R Member 1 (CYP2R1) genes are one of the vital genes involved in the vitamin D (vitD) metabolic pathway. Association of genetic polymorphisms in these two genes with 25-hyroxyvitamin D (25(OH)D) level has been reported in several studies. However, this association has been reported to be discrepant among populations from different ethnicities. Therefore, we aimed in this study to investigate association of the two major single nucleotide polymorphisms (SNP) in GC (rs4588 and rs7014) and a SNP (rs12794714) in CYP2R1 in postmenopausal women in Saudi Arabia. METHODS: This study randomly selected 459 postmenopausal women (aged ≥50 years) of multiple ethnicities in Jeddah, Saudi Arabia. Blood samples were collected from all participating women for DNA extraction and for assessment of serum levels of total 25(OH)D, directly measured free 25(OH)D and other biochemical parameters. SNPs in selected vitD related genes (rs4588 in GC, c.1364G > T with transcript ID: NM_001204307.1 and rs7041 in GC, c.1353A > C with transcript ID NM_001204307.1 and rs12794714 in CYP2R1, c.177G > A with transcript ID NM_024514.4) were determined in DNA samples using Sanger DNA sequencing. RESULTS: Minor allele frequency for rs4588, rs7041 and rs12794714 were 0.25, 0.44 and 0.42 respectively. Genotypes of rs7041 showed significant difference in total 25(OH)D level but not in free 25(O)D level (P = 0.023). In comparison, genotypes of rs4588 and rs12794714 did not show any significant difference neither in total nor in free 25(OH)D level. Post hoc test revealed that total 25(OH)D was lower in the rs7041 TT allele compared to the GG allele (P = 0.022). Chi-square test showed that vitD status was associated with rs7041 genotypes (P = 0.035). In addition, rs7041 minor alleles were found to have an association with vitD deficiency with a statistical significant odds ratio (>1) of 2.24 and 3.51 with P = 0.006 and P = 0.007 for TG and GG genotypes respectively. CONCLUSION: The rs7041 SNP in GC was associated with total 25(OH)D level in postmenopausal women in Saudi Arabia, while rs4588 in GC and rs12794714 in CYP2R1 did not show association with total 25(OH)D. Further studies exploring additional variants in vitD related genes are needed to understand genetic factors underlying vitD deficiency in Saudi population.

Association between vitamin D and glycaemic parameters in a multi-ethnic cohort of postmenopausal women with type 2 diabetes in Saudi Arabia.

BACKGROUND: The relationship between vitamin D (VitD) and insulin sensitivity and secretion in type 2 diabetes mellitus (T2D) has been shown to be different amongst different ethnic populations. In Saudi Arabia, where both T2D and VitD deficiency are highly prevalent health concerns, little is known about the relationship between VitD, insulin sensitivity, resistance and the relative importance of ethnicity. Our primary aim in this study was to investigate influence of ethnicity on VitD association with glycaemic profile and to measures of obesity as a secondary outcome, among multiethnic postmenopausal women with T2D in Saudi Arabia. METHODS: A cross-sectional study was conducted at King Fahad Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia. Postmenopausal females (n = 173, age ≥ 50 years) with T2D were randomly selected in this study. Anthropometric measures and fasting blood samples were obtained for all study participants. Several biochemical parameters were measured including 25-hydroxyvitamin D (25(OH)D), glycosylated hemoglobin (HbA1c), insulin, glucose and c-peptide. Surrogate markers for insulin resistance were calculated using Homeostasis Model Assessment 2 for insulin resistance and beta cell activity (HOMA2-IR, HOMA2-ß). RESULTS: Overall, 25(OH)D was inversely associated with fasting glucose (r=-0.165, P = 0.037), insulin (r=-0.184, P = 0.02), C-peptide (r=-0.19, P = 0.015) and HOMA2- IR C-peptide (r=-0.23, P = 0.004). Additionally, serum 25 (OH)D showed a negative correlation with body weight (r=-0.173 P = 0.028), waist and hip circumferences (r=-0.167, P = 0.033; r=-0.22, P = 0.004 respectively) but not with body mass index (BMI) or waist hip ratio (WHR). In the white ethnic group but not in black or Asian population groups, 25(OH)D level was also associated with only serum fasting C-peptide and HOMA2-IR C-peptide and BMI (P < 0.05). CONCLUSIONS: Insulin resistance and obesity were associated with VitD status in T2D in this cohort. Our findings also suggest that these VitD associations in women from white ethnic background are different than in those from black/Asian ethnic backgrounds. Whether VitD supplements are able to improve either obesity and/or insulin sensitivity should be further investigated in different ethnic population groups.

Whole-Exome Sequencing for Identification of Genetic Variants Involved in Vitamin D Metabolic Pathways in Families With Vitamin D Deficiency in Saudi Arabia.

BACKGROUND: Numerous research studies have found an association between vitamin D (vitD) status and single-nucleotide polymorphisms (SNPs) in genes involved in vitD metabolism. It is notable that the influence of these SNPs on 25-hydroxyvitamin D [25(OH)D] levels might vary in different populations. In this study, we aimed to explore for genetic variants in genes related to vitD metabolism in families with vitD deficiency in Saudi Arabia using whole-exome sequencing (WES). METHODS: This family-based WES study was conducted for 21 families with vitD deficiency (n = 39) in Saudi Arabia. WES was performed for DNA samples, then resulting WES data was filtered and a number of variants were prioritized and validated by Sanger DNA sequencing. RESULTS: Several missense variants in vitD-related genes were detected in families. We determined two variants in low-density lipoprotein 2 gene (LRP2) with one variant (rs2075252) observed in six individuals, while the other LRP2 variant (rs4667591) was detected in 13 subjects. Single variants in 7-dehydrocholesterol reductase (DHCR7) (rs143587828) and melanocortin-1 receptor (MC1R) (rs1805005) genes were observed in two subjects from two different families. Other variants in group-specific component (GC), cubilin (CUBN), and calcium-sensing receptor (CASR) gene were found in index cases and controls. Polymorphisms in GC (rs9016) and CASR (rs1801726) were found in the majority of family cases (94 and 88%), respectively. CONCLUSION: In vitD-deficient families in Saudi Arabia, we were able to detect a number of missense exonic variants including variants in GC (rs9016), CUBN (rs1801222), CASR (rs1801726), and LRP2 (rs4667591). However, the existence of these variants was not different between affected family members and non-affected controls. Additionally, we were able to find a mutation in DHCR7 (rs143587828) and a polymorphism in LRP2 (rs2075252), which may affect vitD levels and influence vitD status. Further studies are now required to confirm the association of these variants with vitD deficiency.

Role of inflammatory markers in polycystic ovaries syndrome: In relation to insulin resistance.

OBJECTIVE: To evaluate the relationship between plasma levels of the inflammatory markers tumor necrosis factor-alpha (TNF-α), C reactive protein (CRP), and interlukin-6 (IL-6) with insulin resistance in Saudi women with polycystic ovaries syndrome (PCOS). METHODS: One hundred eighty Saudi women with and without PCOS, aged 22-38 years, were randomly recruited in this age and body mass index matched case-control study. Clinical assessment, anthropometric measurements, and biochemical parameters were determined for all study participants. RESULTS: Levels of TNF-α, IL-6, hs-CRP, insulin, and insulin resistance indices were significantly higher among PCOS group than their age and BMI matched controls (p < 0.05). Results showed that only QUICK-I (ß = -0.247, p < 0.0001, 95% CI: -3.009 to -0.977) independently predicted TNF-α levels after adjustment for potential confounders. CONCLUSIONS: Elevated plasma levels of TNF- α and IL-6 among PCOS women reflects a state of chronic inflammation with potential implication for insulin resistance, independent of obesity.

Impact of interlukin-6 on central obesity measures in women with polycystic ovarian syndrome.

Our aim was to investigate the relationship between plasma interleukin-6 (IL-6) levels with different measures of central obesity among Saudi women with and without polycystic ovarian syndrome (PCOS). One hundred and sixty-four Saudi females, between 22 and 38 years of age, with and without PCOS were enrolled in this case-control study. Physical examination and laboratory tests were completed for every subject. 2/3 of the study population were obese. Fasting serum insulin, plasma IL-6 levels and insulin resistance show significant increase among POCS than the controls (p<.05). Based on linear regression analysis, C-reactive protein (hs-CRP) was the only independent predictor of plasma IL-6 levels, accounting for 4% of the variability in plasma IL-6 (ß = 0.217, p=.005, 95% CI: 0.049-0.275). Coexistence of metabolic and inflammatory factors in PCOS females is accompanied by central obesity which overpowers the effect of insulin resistance, contributing to higher plasma levels of IL-6 and CRP.Impact statementWhat is already known on this subject? Polycystic ovary syndrome (PCOS) is a cluster of many cardiovascular risk factors, but is also known as an inflammatory condition. Insulin resistance and abdominal obesity are classic components of PCOS. High circulatory levels of inflammatory markers in PCOS patients have been reported but it remains unclear whether their elevation is related to PCOS itself, or are a function of abdominal adiposity.What the results of this study add? The relationship between plasma interleukin-6 levels and different measures of central obesity was investigated among Saudi women with and without PCOS. Elevations of proinflammatory cytokines and inflammatory markers were reported in PCOS patients independently of insulin resistance. It remains to be established whether the proinflammatory state in PCOS is primarily due to inflamed adipose tissue.What the implications are of these findings for clinical practice and/or further research? The present study demonstrates that coexistence of metabolic and inflammatory factors in PCOS females are accompanied by central obesity which overpowers the effect of insulin resistance, contributing to higher plasma levels of IL-6 and CRP. Future studies including a larger population are needed to investigate the mechanisms by which IL-6 and hs-CRP promote cardiovascular risk in PCOS patients.

Relationship between serum resistin, body fat and inflammatory markers in females with clinical knee osteoarthritis.

OBJECTIVES: Adipokines have gained much interest in osteoarthritis (OA) pathogenesis studies over the past years in that they play crucial roles in bone and cartilage homeostasis. Obesity is known to be one of the well-recognized and modifiable causes of OA burden. Key mediators in this metabolic link between obesity and OA could be resistin, among other cytokines secreted by the adipose tissue. We aimed to evaluate the association of serum resistin with obesity, and inflammation in female patients with knee OA. METHODS: One hundred female participants, aged above 40 years, with symptomatic primary knee OA were matched for age with 100 apparently healthy females in a case-control study design. All study participants were subjected to clinical examination, laboratory investigations and radiological examination. RESULTS: Patients with primary knee OA had elevated levels of serum resistin compared with healthy controls. We demonstrated that elevated serum resistin positively correlated with adiposity measures, inflammatory markers and WOMAC index. High sensitivity C reactive protein was found to be an independent predictor of serum resistin levels after adjustment for confounder factors. CONCLUSIONS: These results indicate that resistin may play an important role in the progression of knee OA and may serve as a novel and reliable biomarker for reflecting disease severity, with the potential to contribute to the fundamental processes underlying the pathogenesis of knee OA.

Association between serum resistin, adiposity measures and inflammatory makers in women without cardiovascular diseases.

AIMS: The convergence of obesity and inflammation in the pathogenesis of cardiovascular diseases (CVD) has been recognized over the past decade. Resistin has emerged as a novel secreted protein with links to both insulin resistance and inflammation. We aimed to investigate the relationship between changes in serum resistin levels with metabolic parameters, including obesity and inflammatory markers in women free of CVD. METHODS AND RESULTS: A total of 200 apparently healthy women were consecutively recruited from the Out-patients Clinics at King Abdulaziz university Hospital in Jeddah, Saudi Arabia. They were classified into 4 groups based on quartile for serum resistin. Anthropometric variables were measured in all study subjects. Fasting blood samples were collected for measurement of lipid profile, blood glucose and inflammatory markers. Study subjects within the upper quartile (Q4) had significantly higher body height (p < 0.0001), waist and hip circumferences (p < 0.05) and inflammatory markers (p < 0.0001) values than those in the lower quartile (Q1). Significant correlations were found between circulating resistin levels and systolic blood pressure, some anthropometric measures as well as inflammatory markers. CONCLUSION: Serum resistin levels were found to be increased in overweight and obese women. Resistin was also independently associated with hs-CRP in women free of CVD, suggesting that resistin may be related to low-grade inflammation among obese subjects in the absence of overt CVD.

Relationship between diet quality and carotid intima-media thickness in people with and without carotid atherosclerosis.

BACKGROUND: Dietary assessment and management appear to be essential to limit the impact of cardiovascular risk. AIM: This study aims to assess the association between diet quality as measured by Alternate Healthy Eating Index (AHEI) and coronary risk as determined by carotid artery intima-media thickness (CIMT) among Saudi adults. METHODS: A case-control study was conducted in 210 participants who were matched for age and sex and recruited sequentially from King Abdulaziz University Hospital, Jeddah, Saudi Arabia. Demographic and anthropometric variables were measured in all study participants. Dietary intake was measured by food frequency questionnaire. RESULTS: Obesity was highly prevalent among the study population. The mean AHEI score for the total sample was found to be 58.3 ± 1.67. There were no differences according to the presence and absence of atherosclerotic disease; 45% had a poor diet, and 39% had a diet that needs improvement. Participants with higher CIMT values tended to be of lower AHEI category. Negative correlations were observed between CIMT and AHEI scores and components after adjustment for age and energy intake. CONCLUSIONS: Adherence to a healthier diet, as reflected by a higher AHEI score, is associated with lower coronary risk, as estimated by CIMT value, independently from obesity and personal behavior factors.

Relationship between serum gamma-glutamyltransferase activity and cardiometabolic risk factors in metabolic syndrome.

OBJECTIVES: The objective of this study was to examine the associations of serum gamma-glutamyltransferase (GGT) levels with the metabolic syndrome (MetS) and its components in Saudi adults. METHODS: The study comprised 400 participants (70 men and 330 women), aged between 40 and 88 years, randomly selected from the medicine clinics at the King Abdulaziz University Hospital in Jeddah, Saudi Arabia, in a cross-sectional study design. A standardized questionnaire was used to determine demographics variables, general health, lifestyle habits, and medical history. Anthropometric and biochemical variables measurements were taken for all study participants. MetS was defined according to the American Heart Association/National Heart, Lung, and Blood Institute report, by the presence of abdominal obesity. RESULTS: Higher means for triglycerides and insulin resistance indices (P < 0.0001) was found among those in the second, third, and fourth GGT quartiles as compared with their counterparts in the first quartile. McAuley index (ß = -0.239, P < 0.0001, 95% confidence interval: -4.1--1.5) was shown to be a major determinant of circulating GGT in a multivariate analysis. CONCLUSION: Elevated serum GGT could be a cardiometabolic risk factor either as a mediator of low-grade systemic inflammation and as a mediator of oxidative stress through mediation of extracellular glutathione transport into cells of organ systems.

Serum progranulin levels in relation to insulin resistance in childhood obesity.

BACKGROUND: Progranulin is an adipokine that is involved in the inflammatory response, glucose metabolism, insulin resistance, and may therefore be involved in chronic subclinical inflammation associated with the pathogenesis of childhood obesity. We aimed to investigate the association of circulating progranulin levels with metabolic parameters in children and to assess the importance of progranulin as a biomarker for metabolic diseases. METHODS: A total of 150 children were consecutively recruited from the Pediatric Nutrition Clinics at King Abdulaziz University Hospital in Jeddah, Saudi Arabia. Children were classified into four groups based on quartile for serum progranulin. Anthropometric variables were measured in all study subjects. Fasting blood samples were collected for measurement of blood glucose, insulin and lipid profile. RESULTS: Children within the upper quartile for serum progranulin concentration were heavier, more insulin resistant and had higher concentrations of serum total cholesterol, triglycerides, insulin and high sensitivity C reactive protein compared to those in the lower quartile. On correlation analysis, serum progranulin concentrations were significantly related to general and central adiposity, metabolic parameters, markers of inflammation and insulin resistance. Stepwise multiple regression showed that 26.6% of the variability in serum progranulin could be explained by measures of adiposity. CONCLUSIONS: The increased serum progranulin concentrations were closely related to measures of adiposity, metabolic parameters, inflammatory marker and insulin resistance indices, suggesting that progranulin may be an excellent biomarker for obesity in childhood.

Dietary fruits and vegetables and cardiovascular diseases risk.

Diet is likely to be an important determinant of cardiovascular disease (CVD) risk. In this article, we will review the evidence linking the consumption of fruit and vegetables and CVD risk. The initial evidence that fruit and vegetable consumption has a protective effect against CVD came from observational studies. However, uncertainty remains about the magnitude of the benefit of fruit and vegetable intake on the occurrence of CVD and whether the optimal intake is five portions or greater. Results from randomized controlled trials do not show conclusively that fruit and vegetable intake protects against CVD, in part because the dietary interventions have been of limited intensity to enable optimal analysis of their putative effects. The protective mechanisms of fruit and vegetables may not only include some of the known bioactive nutrient effects dependent on their antioxidant, anti-inflammatory, and electrolyte properties, but also include their functional properties, such as low glycemic load and energy density. Taken together, the totality of the evidence accumulated so far does appear to support the notion that increased intake of fruits and vegetables may reduce cardiovascular risk. It is clear that fruit and vegetables should be eaten as part of a balanced diet, as a source of vitamins, fiber, minerals, and phytochemicals. The evidence now suggests that a complicated set of several nutrients may interact with genetic factors to influence CVD risk. Therefore, it may be more important to focus on whole foods and dietary patterns rather than individual nutrients to successfully impact on CVD risk reduction. A clearer understanding of the relationship between fruit and vegetable intake and cardiovascular risk would provide health professionals with significant information in terms of public health and clinical practice.

Role of omentin-1 and C-reactive protein in obese subjects with subclinical inflammation.

BACKGROUND: While chronic subclinical inflammation is now considered to be a predisposing risk factor of cardiovascular diseases, the extent by which adipokines induce metabolic abnormalities in humans is not fully resolved. The purpose of this study was to examine the relationship between insulin resistance and serum inflammatory markers in obese subjects. METHODS: One hundred and five subjects without any clinically evident CVD were classified into 3 coronary risk levels according to Framingham risk score. Demographic and anthropometric variables were estimated. Serum levels of lipid profile, blood glucose, insulin, omentin-1 and high sensitivity-C reactive protein (hs-CRP) were measured in fasting blood samples. Insulin resistance indices were also calculated. RESULTS: 29% and 62% of the study population were overweight and obese respectively by body mass index (BMI) measures. Almost half of the study population was considered diabetic. There was a tendency for a fall in serum omentin-1 concentrations with increasing coronary risk with a significant increase in hs-CRP levels in the same direction (p < 0.05). Age and fasting blood glucose were found to be independently associated with serum omentin-1 levels. BMI and fasting blood glucose were independent determinants of serum hs-CRP levels. CONCLUSIONS: Omentin-1 might be associated with the development of diabetes mellitus indirectly via insulin activity and obesity. These findings may have important implications for the pathophysiology and therapy of diabetes mellitus by further longitudinal studies.

Bone mineral density and cardiovascular risk factors in postmenopausal women with coronary artery disease.

It has been suggested that osteoporosis and coronary artery disease (CAD) have overlapping pathophysiological mechanisms and related risk factors. The aim of this study was to investigate the association between several traditional cardiovascular risk factors and measures of bone mineral density (BMD) in postmenopausal women with and without clinically significant CAD defined angiographically. A case-control study was undertaken of 180 postmenopausal women (aged between 48 and 88 years) who were recruited from King Abdulaziz University Hospital, Saudi Arabia. Study subjects underwent dual-energy x-ray absorptiometry and coronary angiography. The presence of hypertension, diabetes, dyslipidemia, obesity, smoking and physical activity was identified from clinical examination and history. Demographic, anthropometric and biochemical characteristics were measured. Univariate and multivariate analyses were employed to explore the relationships between cardiovascular risk factors, including BMD, and the presence of CAD. CAD patients were more likely to have a lower BMD and T-score at the femoral neck than those without CAD (P<0.05). Significant differences were found between the groups for fasting lipid profile, fasting blood glucose and anthropometric measures (P<0.05). Conditional logistic regression showed that 3 risk factors were significantly related with the presence of CAD: high-density lipoprotein-cholesterol (odds ratio, OR: 0.226, 95% confidence interval, CI: 0.062-0.826), fasting plasma glucose (OR: 1.154, 95% CI: 1.042-1.278) and femoral neck T-score (OR: 0.545, 95% CI: 0.374-0.794). This study suggests an association of low BMD and elevated CAD risk. Nevertheless, additional longitudinal studies are needed to determine the temporal sequence of this association.

Bronchial asthma and hypovitaminosis D in Saudi children.

BACKGROUND: Asthma, a common lung disease in children, is caused by excessive immune responses to environmental antigens. OBJECTIVE: Given the immuno-modulatory properties of vitamin D, the aim of the current study was to investigate the relationship between vitamin D levels and markers of asthma severity. METHODS: This was investigated in a 70 Saudi children with and without asthma and were recruited from the King Abdul Aziz University Hospital, Jeddah, Saudi Arabia, over the period of 11 months (May 2011-April 2012). Childhood asthma control test instrument was employed to assess the level of asthma control among asthmatic patients. Anthropometric measurements were taken and interviewer-administrated questionnaire was completed for all study participants. Pulmonary function test was performed by recording changes in the peak expiratory flow. Venous blood samples were withdrawn for measurements of vitamin D, bone profile, cytokines profile (interleukin-10, tumor necrosis factor-alpha, platelets derived growth factor), and atopy markers (IgE and eosinophil count). RESULTS: Hypovitaminosis D is highly prevalent among asthmatic children with highly significant increase in several markers of allergy and asthma severity as compared with healthy control children. Significant correlations between several inflammatory and immunological markers and vitamin D levels were also found. Finally, lower 25-hydroxyvitamin D levels were associated with a higher asthma prevalence in multivariable analysis. CONCLUSION: Our study showed that hypovitaminosis D is highly prevalent in the whole population in addition to a highly significant increase in several markers of allergy and asthma severity among asthmatic children as compared with healthy control children.

Insulin resistance in Saudi postmenopausal women with and without metabolic syndrome and its association with vitamin D deficiency.

BACKGROUND: There is increasing interest in the non-skeletal effects of vitamin D and the relationship between vitamin D deficiency and chronic conditions such as diabetes mellitus. We aimed to investigate the relationship between surrogate indices of insulin resistance (IR), and vitamin D deficiency/insufficiency in postmenopausal Saudi women with and without metabolic syndrome. METHODS: The study population consisted of 300 postmenopausal women aged 46-88 years enrolled consecutively from women attending the Outpatient Clinics of King Abdulaziz University Hospital. Demographic, anthropometric, and biochemical parameters were recorded. Data were analyzed for women with and without metabolic syndrome. RESULTS: Abdominal obesity, IR, and hypovitaminosis D were highly prevalent within our population sample. Of the components used to define metabolic syndrome; waist circumference, serum triglycerides (TG), high density lipoprotein-cholesterol, and fasting blood glucose (FBG) were significantly related with all surrogate measures of IR. Significant inverse correlations were found between serum vitamin D and serum TG, FBG, and diastolic blood pressure, within the study cohort. CONCLUSIONS: These observations suggest that hypovitaminosis D may be associated with the risk of developing metabolic syndrome. Interrelationships between IR, metabolic syndrome, and hypovitaminosis D are of particular interest in Saudi population, given the high prevalence of these conditions in this region.

Serum osteocalcin is associated with dietary vitamin D, body weight and serum magnesium in postmenopausal women with and without significant coronary artery disease.

Osteoporosis and atherosclerosis often present atypically in postmenopausal women, making clinical recognition difficult. Prospective studies suggest independent associations between bone mass and vascular calcification through vitamin D deficiency as an established predictor of both conditions. We aimed to examine the relationship between serum osteocalcin and vitamin D status in postmenopausal women with and without angiographic evidence of coronary artery disease (CAD). One hundred and eighty postmenopausal women undergoing coronary angiography were selected sequentially from the Catheterization unit of King Abdulaziz University Hospital. Socio-demographic, anthropometric parameters and dietary habits were measured. Biochemical variables were estimated in blood samples. Half of the postmenopausal women did not have significant CAD, 24% had significant CAD in a single and/or double coronary vessels, 26% had significant CAD in three coronary vessels. Mean serum vitamin D concentrations showed that vitamin D deficiency was a common finding in the whole population. Vitamin D and calcium intakes were uniformly low in the study cohort. Serum osteocalcin was significantly correlated with dietary vitamin D in all subgroups (r=-0.172, p<0.05) and positively correlated among the patients (r=0.269, p=0.01). Serum magnesium, alkaline phosphatase, dietary vitamin D, and body weight were independent variables of serum osteocalcin level. In conclusion, elevated levels of serum C reactive protein and vitamin D were associated with low serum osteocalcin levels. Therefore, osteocalcin may be a potential cardiovascular risk marker. However, further studies are needed to clarify the pathophysiological processes underlying the relationship between serum osteocalcin level and atherosclerosis parameters.

Relationship between nutritional profile, measures of adiposity, and bone mineral density in postmenopausal Saudi women.

BACKGROUND: Osteoporosis remains a major health problem in all developed countries and is a condition in which several dietary factors have been implicated. OBJECTIVE: To assess the nutritional status and levels of adiposity of postmenopausal women in relation to bone mineral density. DESIGN: A cross-sectional study in which dietary intake was estimated by a food frequency questionnaire in 300 Saudi postmenopausal women aged 46-88 years. Bone profile biochemistry (serum calcium, phosphate, parathyroid hormone [PTH], vitamin D) and bone mineral density (BMD) in 3 skeletal sites were determined for all participants. RESULTS: Overweight and obesity were highly prevalent among the study population. No significant correlation was found between dietary calcium and vitamin D and bone mass at any site. Dietary intake of calcium and vitamin D was significantly less than the recommended levels for a large proportion of the cohort. Energy-adjusted intakes of carbohydrates, fat, protein, and unsaturated fatty acids were associated with BMD in the postmenopausal women. Age, body weight, and residency type were predictors of BMD at all sites. Serum-intact PTH was a predictor of BMD at lumbar spine and femoral neck. Waist : hip ratio (WHR) was a predictor for BMD at femoral neck. CONCLUSIONS: These results suggest that BMD is influenced by dietary factors other than calcium and vitamin D. However, nondietary factors such as age, WHR, PTH, and body weight may be important determinants of BMD in postmenopausal women.