Dietary Patterns and Hypothyroidism in U.S. Adult Population.

The thyroid gland produces hormones that are essential for various body functions. Hypothyroidism is defined as insufficient thyroid hormone production. Several studies have found associations between specific micronutrients and overall thyroid function; however, the amount of evidence regarding the relationship between dietary patterns and hypothyroidism among the U.S. population is limited. Data from three cycles of National Health and Nutrition Examination Surveys (NHANES), 2007-2008, 2009-2010, and 2011-2012, were used (n = 8317). Subjects with serum thyroid stimulating hormone >4.5 mIU/L or on levothyroxine were considered to have hypothyroidism. Age, sex, race/ethnicity, body mass index, and several lifestyle factors were considered as covariates. Three patterns were extracted using factor analysis. These were labeled as fat-processed grains-sugars-meats (FPSM), oils-nuts-potatoes-low-fat meats (ONPL), and fruits-whole grains-vegetables-dairy (FWVD) patterns. In a weighted multiple logistic regression, FPSM and ONPL were inversely associated with hypothyroidism (OR, 0.75; 95% CI, 0.57-1; p = 0.049 and OR, 0.81; 95% CI, 0.67-0.97; p = 0.025, respectively). However, FWVD demonstrated no association with hypothyroidism (p = 0.63). In conclusion, FPSM and ONPL patterns but not FWVD patterns were associated with hypothyroidism in U.S. adults. Nutrient deficiencies and their interactions may be linked to hypothyroidism.

Impact of metformin treatment on cobalamin status in persons with type 2 diabetes.

Over the last decades, low vitamin B12 status has been reported in individuals with type 2 diabetes mellitus (T2DM). Metformin, the first-line therapy for lowering blood glucose, is the main driving factor behind this association. Although the relationship between vitamin B12 deficiency and metformin is well established, results of studies on the exact effect of the dose and duration of the therapy remain inconsistent. Additionally, a lack of consensus on the definition of vitamin B12 deficiency adds to the conflicting literature. The objectives of this review were to analyze and synthesize the findings on the effects of metformin dose and duration on vitamin B12 status in patients with T2DM and to outline the potential mechanisms underlying metformin's effect on vitamin B12. Metformin therapy has adversely affected serum vitamin B12 concentrations, a marker of vitamin B12 status. The metformin usage index (a composite score of metformin dose and duration) might serve as a potential risk assessment tool for vitamin B12 screening in patients with T2DM. Considering the health implications of suboptimal vitamin B12 status, vitamin B12 concentrations should be monitored periodically in high-risk patients, such as vegans who are receiving metformin therapy for T2DM. Additionally, it is prudent to implement lifestyle strategies concurrent with metformin therapy in individuals with T2DM, promoting an overall synergistic effect on their glycemic control.

Intended and Unintended Benefits of Folic Acid Fortification-A Narrative Review.

Inadequate folate intake during pregnancy is the leading cause of the development of neural tube defects (NTDs) in newborns. For this reason, mandatory fortification of folic acid, a synthetic, easily bioavailable form, in processed cereals and cereal products has been implemented in the US since 1 January 1998 to reduce the risk of NTD in newborn children. This report aimed to review the literature related to the impact of mandated folic acid fortification on the intended and unintended benefits to health. Potential adverse effects were also discussed. We searched Pubmed, Google Scholar, Embase, SCOPUS, and Cochrane databases for reports. About 60 reports published between January 1998 and December 2022 were reviewed, summarized, and served as background for this review. The intended benefit was decreased prevalence of NTDs, while unintended benefits were reduction in anemia, blood serum homocysteine, and the risk of developing cardiovascular diseases. Potential issues with folic acid fortification are the presence of unmetabolized folic acid in circulation, increased risk of cancer, and the masking of vitamin B-12 deficiency. From a health perspective, it is important to monitor the impact of folic acid fortification periodically.

Vitamin D, Gut Microbiota, and Cardiometabolic Diseases-A Possible Three-Way Axis.

Metabolic syndrome (MetSyn) is a precursor for several cardiometabolic diseases such as obesity, type-2 diabetes mellitus (T2DM), and cardiovascular diseases. Emerging evidence suggests that vitamin D deficiency links to cardiometabolic diseases through microbiota. A combination of poor vitamin D status and dysbiosis may contribute to the progression of cardiometabolic diseases. Therefore, in this review, we present the relationship among vitamin D, microbiota, and cardiometabolic diseases with a focus on MetSyn. We searched major databases for reports on vitamin D, microbiota, and MetSyn until June 2022. We reviewed 13 reports on the relation between vitamin D and MetSyn (6 randomized controlled and 7 cross-sectional studies) and 6 reports on the effect of vitamin D on the gut microbiome. Adequate vitamin D status has a beneficial effect on gut microbiota, therefore preventing the progression of MetSyn. Further, well-controlled studies are needed for a better understanding of the mechanisms of action involving vitamin D and microbiota in the pathogenesis of cardiometabolic diseases.

Association between food intake patterns and serum vitamin D concentrations in US adults.

The objective of this study was to investigate the association between food patterns and serum vitamin D concentrations in US adults. Data from two cycles of National Health and Nutrition Examination Surveys, 2003-2004 and 2005-2006, were used (n 6637). Three major food patterns were derived using factor analysis. These three patterns were labeled as meat and processed meat foods (MPF), vegetables, fruit, nuts, and whole grains (VFNW), and sweet, snack, and beverage pattern (SSB). Serum vitamin D was measured with RIA and later standardized to reflect the assay changes over time. In multivariate-adjusted regression analysis, the MPF pattern was significantly, inversely associated with serum vitamin D concentrations (P < 0·001). However, the relation between the VFNW pattern and serum vitamin D was non-linear (P < 0·001). There was no relationship between SSB pattern and serum vitamin D in US adults. In conclusion, persons with a high intake of meat and processed meats are associated with lower serum vitamin D concentrations. Reducing processed foods and emphasizing VFNW will be beneficial from a health perspective.

Sarcopenia and Mortality in Critically Ill COVID-19 Patients.

COVID-19 can manifest as either asymptomatic or progressing to a severe phase in some patients, which may require hospitalization. These patients may experience dyspnea and hypoxia, leading to the development of acute respiratory distress syndrome. Studies have reported an increased risk of severe sarcopenia in COVID-19 patients during and after recovery. This narrative review aimed to summarize and synthesize available studies on the association between sarcopenia and mortality in critically ill COVID-19 patients. A total of 22 studies conducted on hospitalized COVID-19 patients were included in this review. Of those, 17 studies reported a direct association, while 5 studies showed no association between sarcopenia and mortality in severe COVID-19 patients. It is important to maintain muscle quality and quantity in defense against COVID-19. The measurement of lean muscle mass should be included in the risk assessment of severely ill COVID-19 patients as part of the therapy plan.

Hypovitaminosis D and Metabolic Syndrome in Postmenopausal Women.

Metabolic syndrome (MetSyn) is a precursor for several cardiometabolic diseases. The prevalence of MetSyn is higher in postmenopausal women compared to premenopausal women. The role of vitamin D in postmenopausal women is not clearly understood. Hypovitaminosis D is more prevalent in postmenopausal women compared to premenopausal women. For this review, Pubmed, Cochrane, SCOPUS, Embase, and Google Scholar databases were searched up to August 2022. Findings from one randomized controlled trial (RCT) and ten cross-sectional studies were included in this review. Several cross-sectional studies (8 out of 10 reviewed) unequivocally demonstrated an inverse association between serum 25-hydroxyvitamin D concentrations and MetSyn. However, RCTs are severely lacking in the effect of vitamin D intake on the biomarkers of MetSyn and the prevalence of MetSyn. Therefore, caution should be used in recommending mega doses of vitamin D supplements for postmenopausal women because of the potential adverse effects associated with this vitamer.

Intravenous Ascorbic Acid and Lung Function in Severely Ill COVID-19 Patients.

Current evidence suggests that ascorbic acid improves the host's immune system and, therefore, may play a role in reducing the severity of infectious diseases. Coronavirus disease 2019 (COVID-19) is a potentially life-threatening viral infection that mainly infects the lungs. The objective of this review was to synthesize the existing findings from studies related to the effect of intravenous ascorbic acid on lung function in COVID-19 patients. For this review, PubMed, Cochrane, SCOPUS, EMBASE, Clinical Trial Registry, and Google Scholar databases were searched from December 2019 to May 2022. There was a total of six studies that investigated the large dose of ascorbic acid infusion intravenously on lung function in severely ill subjects with COVID-19. Out of six, three studies found that high-dose intravenous ascorbic acid improved lung function markers, and three studies found null results. Infusions of 12 g/d and 24 g/d of intravenous ascorbic acid had shown a significant improvement in lung function markers in two clinical trials. Studies that administered 8 g/d, 2 g/d, and 50 mg/kg/d of intravenous ascorbic acid found no influence on mechanical ventilation need and other lung function markers in critically ill subjects with COVID-19. Overall, the effect of intravenous ascorbic acid on the lung function of subjects with COVID yielded equivocal findings. More double-blinded, randomized, clinical studies with a larger sample size are required to confirm the effect of ascorbic acid in ameliorating the lung pathologies associated with COVID infection.

Association of Serum 25-Hydroxyvitamin D Concentration with Breast Cancer Risk in Postmenopausal Women in the US.

The association between serum 25-hydroxyvitamin D [25(OH)D] concentration and breast cancer risk in postmenopausal women is not well understood. The aim of this study was to investigate the association between serum 25(OH)D concentration and breast cancer in postmenopausal women in the United States using nationally representative sample surveys. We used the data from seven cycles of National Health and Nutrition Examination Surveys from 2001 to 2014. Participants were non-institutionalized postmenopausal women (n = 8108). In restricted cubic spline analysis, a significant, nonlinear, invert 'U' relationship was observed between serum 25(OH)D concentrations and breast cancer in postmenopausal women (p = 0.029). Overall, breast cancer risk was highest (OR = 1.5) between 70 nmol/L and 80 nmol/L of serum 25(OH)D concentration. Then after serum 25(OH)D 80 nmol/L concentration, the breast cancer risk declined. In multivariate-adjusted logistic regression, the risk of having breast cancer was significantly higher in serum 25(OH)D 75−˂100 nmol/L category compared to the 25(OH)D < 30 nmol/L category [OR and 95% CI: 2.4 (1.4−4.0)]. In conclusion, serum vitamin D concentrations ≥ 100 nmol/L are associated with reduced risk of breast cancer in postmenopausal women. Controlled trials are required to verify if serum 25(OH)D ≥ 100 nmol/L offers protection against breast cancer in postmenopausal women.

The Impact of Mineral Supplementation on Polycystic Ovarian Syndrome.

Polycystic ovary syndrome (PCOS) is an endocrinopathy that is common among women of reproductive age. It is a heterogeneous disorder with an unknown etiology. Different strategies have been proposed for the treatment of PCOS. Recent studies recommend supplementation with specific minerals for treating various PCOS phenotypes. We searched PubMed, Google Scholar, and SCOPUS databases by using search terms combining PCOS with the supplementation of magnesium, zinc, selenium, or chromium. This review presents a narrative concerning the association between PCOS and magnesium, zinc, selenium, and chromium supplementation. We review findings from various randomized controlled trials and meta-analyses conducted in women of childbearing age with PCOS. Recent reports highlight the beneficial effect of minerals on the clinical and metabolic symptoms of PCOS. Further studies are required to establish the appropriate dosage level of these minerals for ameliorating the pathologies associated with PCOS because of the potential health risks linked with higher doses.

Fast food and sweet intake pattern is directly associated with the prevalence of asthma in a Qatari population.

OBJECTIVE: The relationship between dietary patterns and the prevalence of asthma is not well understood. We aimed to investigate the association between dietary patterns and asthma in adults in Qatar. METHODS: In this study, cross-sectional data from the Qatar Biobank were used (n = 986). Participants were Qatari or long-term Qatar residents aged ≥20 years old. A food frequency questionnaire was used to collect dietary intakes. Three dietary patterns were identified using factor analysis. Multivariable logistic regression was used to assess the association between dietary patterns scores and asthma. RESULTS: Among 986 eligible participants, 6.6% (n = 65) reported that they were diagnosed with asthma. Three dietary patterns were identified. These were (1) "Traditional" (high intake of rice, chicken/meat/fish, and breads); (2) "Prudent" (high intake of fruits, vegetables, and fish); and (3) "Fast Food/Sweets" (high intake of desserts, fast food, and soft drinks). The fast food/sweet dietary pattern was associated with increased likelihood of having asthma [comparing high vs. low tertile, OR for asthma = 1.25; 95% CI (1.02-1.54); p = 0.035]. Traditional and Prudent dietary patterns were not associated with the prevalence of asthma. CONCLUSION: The fast food/sweet dietary pattern was directly associated with the prevalence of asthma among adults in Qatar. Reducing the fast foods and sugary-rich foods may be beneficial for respiratory health.

Temporal Relation between Double Fortification of Wheat Flour with Iron and Folic Acid, and Markers and Prevalence of Anemia in Children.

Fortification of wheat flour with iron and folic acid became mandatory in Ivory Coast in 2007. The purpose of this study was to determine the time trend relation between mandatory double fortification of wheat flour with iron and folic acid and markers and prevalence of anemia by comparing the data between pre- and post-fortification periods in Ivory Coast children. Data were derived from the pediatric unit of the University Hospital of Treichville, Abidjan, Ivory Coast. Medical records of 467 children from 5 to 14 years old were analyzed from the years 2004 through 2010. Periods from 1 January 2004 to 31 December 2006 and 1 January 2008 to 31 December 2010 were considered as pre- and post-fortification periods, respectively. Data on hemoglobin, hematocrit, red blood cell count (RBC), mean corpuscular volume (MCV), and anemia between pre- and post-fortification periods were compared. There were no significant differences in hemoglobin, hematocrit, RBC, and prevalence of anemia between pre- and post-fortification periods. However, MCV in post-fortification period was significantly higher compared to pre-fortification period in all subjects (77.6 fL vs. 76.8 fL; p = 0.02) and in young girls (79.1 fL vs. 75.2 fL; p = 0.01). Lack of significant differences in anemia and in markers of anemia between pre- and post-fortification periods need further investigation in children of Ivory Coast.

Serum 25-hydroxyvitamin D concentrations are inversely associated with body adiposity measurements but the association with bone mass is non-linear in postmenopausal women.

Vitamin D deficiency has been linked to increased adiposity and decreased bone density. It is not known if vitamin D is linked to adiposity measures and bone mass in postmenopausal Qatar women. We investigated an association between serum vitamin D [25-hydroxyvitmain D (25(OH)D)] and adiposity measurements in postmenopausal women using Qatar Biobank data (n = 935). The post-menopausal status was self-reported by participants. Multivariate adjusted regression was applied to determine the association between serum 25(OH)D and body adiposity markers and bone mass. Serum 25(OH)D was significantly, inversely associated with body mass index (p < 0.0005), waist circumference (0.044), fat mass (p < 0.003), gynoid fat (p < 0.001), and android fat (p < 0.009). Serum 25(OH)D appeared to have an inverse 'U' association with several adiposity measures. Overall, body adiposity markers were the lowest in the 4th quartile serum 25(OH)D and significantly lower compared to the 1st quartile serum 25(OH)D. In multivariable adjusted analysis, no association was found between serum 25(OH)D concentration and bone mass when serum 25(OH)D was categorized. In a continuous variable analysis, the association between 25(OH)D and bone mass was significant, non-linear, inverse 'U'. In conclusion, serum 25-hydroxyvitamin D was inversely associated with adiposity measures and non-linearly associated to bone mass in postmenopausal Qatari women.

Visceral adiposity index is a better predictor of type 2 diabetes than body mass index in Qatari population.

The prevalence of type 2 diabetes (T2D) has increased recently in Qatar. Body mass index (BMI) is a predictor of T2D in many populations. However, BMI is based on height and weight measurements and not on body adiposity. Therefore, the utility of BMI for predicting the risk of T2D has been questioned. Visceral adiposity appears to be a better predictor of T2D.This study aimed to assess the relative effectiveness of visceral adiposity index (VAI) and body adiposity index (BAI), in comparison with BMI, for T2D among Qatari adults.A random sample of 1103 adult Qatari nationals and long term residents over 20 years old were included in this study. This data were obtained from the Qatar Biobank (QBB). We performed a multivariate logistic regression to examine the association between VAI, BAI, BMI, and T2D, and computed z-scores for VAI, BAI and BMI.VAI z-scores showed the strongest association with the risk of T2D (OR, 1.44; 95% CI: 1.24-1.68) compared with the z-scores for BAI (OR, 1.15; 95% CI: 0.93-1.43) and BMI (OR, 1.33; 95% CI: 1.11-1.59). ROC curve analysis showed that VAI was a stronger predictor than BAI and BMI (P < .0001). Subgroup analysis indicated that the association was stronger between VAI and T2D in Qatari women than in men.VAI was a stronger and an independent predictor of T2D compared to BAI and BMI among the Qatari adult population. Therefore, VAI could be a useful tool for predicting the risk of T2D among Qatari adults.

Author Correction: Serum vitamin D is associated with improved lung function markers but not with prevalence of asthma, emphysema, and chronic bronchitis.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Serum vitamin D is associated with improved lung function markers but not with prevalence of asthma, emphysema, and chronic bronchitis.

Hypovitaminosis D has been linked to several non-bone diseases. Relation between 25-hydroxyvitamin D [25(OH)D] and lung function and lung diseases has received little attention at the global level. Cross-sectional data from three National Health and Nutrition Examination Surveys, 2007-2008, 2009-2010, and 2011-2012 were used to investigate the relationship between serum 25(OH)D concentrations and lung function makers [forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1)] and lung diseases (asthma, emphysema, and chronic bronchitis) with multivariate regression models (n = 11,983; men, 6,010; women, 5,973). Serum 25(OH)D concentrations were directly associated with FVC and FEV1 (P for trend < 0.01). Individuals in the 4th quartile serum 25(OH)D had significantly higher FVC and FEV1 compared to those in the 1st quartile (P < 0.01). When data were stratified based on gender and smoking status, we found similar associations between serum 25(OH)D concentrations and lung function markers. There was no relation between serum 25(OH)D and prevalence of asthma, chronic bronchitis, and emphysema in US adults. Serum 25(OH)D concentration is associated with improved lung function markers but not with the prevalence of asthma, emphysema, and chronic bronchitis. Controlled studies are needed to determine if the vitamin D supplementation improves lung function in adults and in smokers.

Dietary patterns and cardiovascular disease risk among Chinese adults: a prospective cohort study.

BACKGROUND AND OBJECTIVE: We aimed to examine the prospective association between dietary patterns and cardiovascular disease (CVD) risk in Chinese adults. METHODS: Adults aged ≥20 years in the China Health and Nutrition Survey (open cohort) were followed between 1991 and 2011. Participants may enter the cohort at any wave. Dietary intakes were obtained from a 3-day, 24-h recall combined with household weighing for oil and condiments. CVD was defined as having either myocardial infarction or stroke. Two sets of dietary patterns were derived using reduced rank regression and factor analysis. Iron-related dietary pattern (IDP) was generated using iron intake as a response variable. Multivariable Cox regression was used to analyse the relation between dietary patterns and CVD risk. RESULTS: In total, 13,055 adults were followed for a median of 9 years. During 115,368 person years of follow-up, 502 participants developed CVD. Two dietary patterns were derived and labeled as traditional dietary pattern (high intake of rice, pork, fish, poultry, and fresh vegetable but low intake of wheat) and modern dietary pattern (high intake of fruit, soymilk, and fast food). Across the quartiles of intake, the hazard ratio (95% CI) for CVD were 1.0, 0.84 (0.64-1.10), 0.57 (0.42-0.77), and 0.58 (0.42-0.79) for traditional pattern (p for trend <0.001) and 1.0, 1.56 (1.16-2.09), 1.56 (1.13-2.14), and 1.68 (1.16-2.44) (p for trend = 0.118) for modern pattern. IDP was characterised by high intake of fresh vegetable, wheat, legume, beverage, offal, rice, and whole grain. IDP intake was not associated CVD. Comparing extreme quartiles, high rice intake was associated with halved while wheat intake was associated with a doubled risk of CVD. CONCLUSIONS: Traditional dietary pattern and rice intake are inversely but modern dietary pattern and wheat is directly associated with CVD risk. IDP is not related to CVD in Chinese adults.

Serum Magnesium and Cognitive Function Among Qatari Adults.

Background: Previous studies found that low blood magnesium increases the risk of several diseases such as cardiovascular diseases (CVD), diabetes, and hypertension. These ailments are associated with declined cognitive function. Objective: We aimed to examine the association between serum magnesium and cognitive function among Qatari adults. In addition, we assessed the interaction relation between low serum magnesium, hypertension, and diabetes in relation to cognitive function. Method: Data from 1,000 Qatari participants aged ≥20 years old who participated in the Qatar Biobank (QBB) Study were analyzed. Serum magnesium was measured by an automated calorimetric method and suboptimal magnesium was characterized by <0.85 mmol/l. Cognitive function was determined by measuring the mean reaction time (MRT) based on a computer-based, self-administered test. Multivariable linear regression was used to examine the relation between serum magnesium concentrations and cognitive function. Results: The prevalence of suboptimal magnesium was 57.1%. Across the four quartiles of serum magnesium from the lowest to the highest, the regression coefficients (95% CI) for MRT were 0 (reference), -17.8, -18.3, and -31.9 (95% CI 2.4-3.1; p for trend 0.05). The presence of hypertension and diabetes significantly increased the MRT. Women with suboptimal magnesium and hypertension had the highest MRT. Conclusion: The prevalence of suboptimal magnesium is high in Qatar. There was a direct association between serum magnesium and cognitive function. Low magnesium concentrations were associated with a longer MRT.

Serum Vitamin D Concentration ≥75 nmol/L Is Related to Decreased Cardiometabolic and Inflammatory Biomarkers, Metabolic Syndrome, and Diabetes; and Increased Cardiorespiratory Fitness in US Adults.

A serum vitamin D [25-hydroxyvitamin D, 25(OH)D] concentration of ≥75 nmol/L is recommended for optimal health. We investigated the relationship between serum 25(OH)D and metabolic syndrome (MetS), diabetes, cardiometabolic biomarkers, and cardiorespiratory fitness (CRF) in US adults using clinical cut points recommended by health organizations. Data from USA's National Health and Nutrition Examination Surveys were used. Prevalences and likelihood of having MetS and diabetes according to clinical cut points for serum 25(OH)D (<30 nmol/L, 30-<50 nmol/L, 50-<75 nmo/L, and ≥75 nmol/L) were determined with multivariate logistic regression. Relations between serum 25(OH)D and various cardiometabolic biomarkers, CRF, MetS, and diabetes were tested using multivariable adjusted regression. Prevalence of MetS and diabetes were significantly lower in individuals with serum 25(OH)D ≥75 nmol/L (MetS, 21.6%; diabetes, 4.1%) compared to those with 25(OH)D <30 nmol/L (MetS, 45.5%; diabetes, 11.6%) (p < 0.0001). Individuals with serum 25(OH)D ≥75 nmol/L had significantly lower waist circumference (p < 0.0001), C-reactive protein (p = 0.003), glycated hemoglobin (p < 0.0002), fasting triglycerides (p < 0.0001), total homocysteine (p < 0.0001), and insulin resistance (p = 0.0001) and had significantly higher HDL-cholesterol (p < 0.0001) and maximal oxygen uptake (marker for CRF) (p< 0.0009) compared to those with 25(OH)D <30 nmol/L. In conclusion, serum 25(OH)D ≥75 nmol/L is associated with positive indicators related to cardiometabolic diseases in US adults.

Validation of Vitamin D-Specific Food Frequency Questionnaire against Food Records for Qatari Women.

The measurement of vitamin D nutritional status through dietary assessment is cost effective. Food frequency questionnaire (FFQ) is usually validated against food records (FR). There is no vitamin D-specific FFQ for Qatar population. The objective of this study was to develop a vitamin D-centric FFQ and validate FFQ against three-day FR for Qatar population. A quantitative FFQ based on vitamin D containing foods consumed in Qatar was developed. Vitamin D contents of foods were gathered from food labels and food composition tables from the United States Department of Agriculture. A vitamin D content database was developed for this study purpose. Dietary intakes while using FFQ and three-day FR were collected from 62 women. Vitamin D intakes from FFQ and three-day FR were validated with quartile comparison and Bland-Altman (BA) tests. BA plot showed an agreement between FFQ and three-day FR vitamin D intakes. The BA index was 3.23%, which is <5%, a commonly used standard for validation. Quartile correlation showed that ≈73% of subjects were within the same or adjacent quartile. In conclusion, an agreement was found between vitamin D intakes from FFQ and three-day FR in Qatari women. More studies are needed to validate the vitamin D-specific FFQ in Qatari population at large.