The Impact of Life Style & Dietary Habits on Vitamin D status Among Young Emiratis Fatme Al Anouti, Ph.D. Zayed University, Abu Dhabi
The Sun-Shine Vitamin Vitamin D is unique because it can be synthesized in body unlike all other vitamins. Sources of Vitamin D: Sun exposure Diet (eggs & salmon) VTD supplementation
Active Forms of Vitamin D
Functions Mediated by VTD Regulates calcium and bone metabolism Vitamin D Receptors(VDRs) have been found in almost every type of human cell. Vitamin D controls (directly or indirectly) + 3000 genes modulate immunity, control cell growth & maturation, regulate production of insulin & renin, induce apoptosis & inhibit angiogenesis.
Functions Mediated by VTD Vitamin D D3/D2 D3/D2 Regulation of blood pressure and insulin production (Heart Disease and diabetes prevention) calcium intestinal absorption & skeletal and bone integrity Regulation of immune function (prevention of autoimmune diseases such as type 1 diabetes, multiple sclerosis, rheumatoid arthritis ) Regulation of cell growth (Cancer prevention)
Premature aging of skin of VDR knockout mice (KO) is visible at the age of 8 9 months Vitamin D appears to control the basic mechanism of aging
A Common Problem in the Present Century 1. Very few foods naturally contain VTD and only a few foods are fortified. 2. Life Style: people spend most time indoors (a study conducted at Boston Medical Center revealed that 32% of medical students and doctors were VTD deficient) (Holick, 2008). 3. The exaggerated Safe Sun Message and excessive use of sunscreens SPF 8 & SPF 15 reduce Vitamin D production by 95% & 99%, respectively
The D-Dilemma: To Screen or Not to Screen for 25(OH)D? Michael F. Hollick, Clinical Chemistry,56:729-731(2010) With the recognition of widespread vitamin D deficiency/insufficiency in children and adults, there is no need to measure everybody's blood 25(OH)D. It would be much more cost-effective to implement a vitamin D supplementation program for all children and adults until there is higher fortification of vitamin D in foods and drinks
Guidelines for Healthy VTD Levels 25(OH)D (nmol/l) Vitamin D status < 20 Deficiency 20 50 Insufficiency 51 200 Sufficiency > 200 Toxicity Hollick, 2009 American Association for Clinical Chemistry
Updated Vitamin D Status Serum 25(OH)D Vitamin D Clinical/Biochemical (nmol/l) Status Alterations < 25 Severely Deficient Rickets, osteomalacia, myopathy, calcium malabsorption, severe hyperparathyroidism, impaired immune and cardiac function. 25 49 Deficient Reduced bone mineral density, impaired muscle function, low intestinal calcium absorption rate, elevated PTH. 50 74 Insufficient Low bodily stores of 25(OH)D, elevated PTH 75-374 Sufficient No disturbances of D-dependent functions > 375 Toxic Soft tissue calcification, hypercalcemia Zittermann A et al. Current Opin Clin Nutr & Metabolic Care 2009,12: 634 639
25(OH)D (nmol/l) The Upper Limit of Possible 25(OH)D is 150-200 nmol/l 250 200 150 150 160 200 100 50 0 HI/WI Farmers Outdoor Workers Am J Clin Nutr 80,1645-1649, 2004; J Clin Endocrinol Metab 87,4952-4956,2002
Is Vitamin D Toxic? Excessive exposure to sunlight does not lead to overproduction of vitamin D. Supplemental vitamin D in certain clinical settings may have toxicity. However, there are no reported deaths due to toxicity Symptoms are largely hypercalcaemia, high blood pressure, headache, fatigue, loss of appetite, kidney damage, joints & muscle pain.
Recommendations: 400-1000 IU/day for infants 1000-1500 IU/day for Children 1-10 years 1500-2000 IU/day for teenagers and adults Michael F. Holick, Clinical Chemistry, 56:729-731(2010)
500+ Clinical Trials Related to Vitamin D Bone 84 Calcium 51 Osteoporosis 51 Kidney 44 Renal 28 Postmenopausal 25 Hyperparathyroidism 20 Prostate 19 Obese 19 Breast Cancer 16 Fracture 15 Diabetes 12 HIV 10 Elderly 9 Tuberculosis 9 Chronic Obstructive Pulmonary Disease 7 Colon 6 Multiple Sclerosis 5 Blood Pressure 5 Muscle 5 Cystic Fibrosis 5 Hip 5 Rheumatoid Arthritis 5 Lung 4 Psoriasis 4 Lupus 4 Crohn's 4 Knee 3 Heart 9 Rickets 7 http://clinicaltrials.gov/
Vitamin D Deficiency in the Gulf Countries A study in Kuwait revealed that VTD deficiency was common in veiled Kuwaiti women El-Hajj Fuleihan GE et. al. J.Clin.Endocrinol.Metab.200 6,91:405-412 A study conducted on 433 school girls, revealed that VTD deficiency was highly prevalent (81%) among adolescent females. A study showed that VTD deficiency is common in women of child-bearing age (33 subjects) in Arab communities residing in the UAE
Research Study Not enough data to document the prevalence of Vitamin D deficiency among UAE nationals. Objectives of the study Assess the Prevalence of VTD deficiency among a representative sample of the young adult Emirati population Evaluate the influence of sun avoidance attitude, diet and life style (psychosocial factors) on VTD status Investigate whether VTD deficiency is related to depression among young Emiratis
There is a positive relationship between vitamin D deficiency on one hand & overweight, sun avoidance behaviors, depression & low intake of vitamin D rich foods on the other
Methodology Cross Sectional Study design with 2 cohorts (summer & winter) randomly selected from ZU (Abu Dhabi) to investigate seasonal variation of Vitamin D status The sample size was calculated according to power estimate: n= t 2 xp(100-p)/m 2 n = required sample size t = confidence level at 95%(standard value of 1.96) p = estimated prevalence of the disease in the project area m = margin of error at 5%
FFQ (Food Consumption and Diet) Methodology A total of 278 participants (female, 208; male, 70) were recruited The study recruitment was conducted in October 2009 (n = 138 females and n = 70 males) and in April 2010 (n = 70 females) Data collection: Blood test to measure serum 25(OH)D by HPLC (Waters 2695) & a questionnaire that had several components pertaining to socio-demographic (residential, educational, and occupational), medical history, nutritional (FFQ), 3 and psychosocial (personality traits, depression, anthropometry) aspects. Sun Avoidance Inventory (SAI) to assess attitude towards sun avoidance in the context of VTD deficiency BDI (Beckman Depression Inventory)
Data was statistically analyzed using SPSS 18 Differences in 25(OH)D concentrations by gender & season were analyzed with Lavene s test. Comparisons of serum 25(OH)D concentrations were performed by using the Student t test Correlation between 25(OH)D & independent variables (FFQ, BMI, depression & SAI) were determined by Pearson correlation coefficient Results
% of Students Vitamin D Status 80 70 UAE STUDENTS FROM ZAYED UNIVERSITY 68 60 50 40 30 20 26 <25 25-49 50-75 >75 10 0 5 1 <25 25-49 50-75 >75 Vitamin D (nmol/l)
Sun Avoidance
Body Mass Index Distribution
Group Statistics for BDI Group Statistics Gender N Mean Std. Deviation Std. Error Mean BDI_Total Female 208 13.9851 7.98117.68947 Male 70 12.8082 9.62297 1.12628
Group Statistics for FFQ Descriptive Statistics N Minimum Maximum Mean Std. Deviation FFQ 278 5.00 36.00 14.5829 5.78969
Baseline characteristics of male & female students Characteristic Males (n = 70) Females (n = 208) t-test (sig. 1-tailed) 95% Confidence Interval of the Difference Age (years) 21.0 ± 4.6 20.8 ± 4.0 0.211 BMI (kg/m 2 ) 23.7 ± 4.2 23.2 ± 5.0 0.057 25 (OH)D (nmol/l) 27.3 ± 15.7 24.2 ± 14.9 0.0025* SAI score 34.6 ± 7.0 39.42 ± 7.4 0.000* FFQ score 17.4 ± 5.8 12.50 ± 4.9 0.064 * Differences are significant; p<0.05 All values are shown as mean ± SD. BMI, body mass index; SAI, sun avoidance inventory; FFQ, food frequency questionnaire.
Baseline characteristics of females in summer & winter Characteristic t-test (sig. 1-tailed) 95% Confidence Interval of the Difference Females (summer) (n = 138) Females (winter) (n = 70) Age (years) 21.1 ± 4.6 20.3 ± 1.9 0.106 BMI (kg/m 2 ) 22.6 ± 4.6 24.4 ± 5.6 0.30 25 (OH)D (nmol/l) 20.9 ± 14.9 31.3 ± 12.3 0.0005* SAI score 41.4 ± 7.4 35.1 ± 5.4 0.000* * Differences are significant; p<0.05 FFQ score 13.2 ± 5.4 11.0 ± 3.2 0.003
D Relations between Vitamin D, SAI, BDI, & BMI Correlations SAI Total BDI_Total Body Mass Index Pearson Correlation D SAI Total BDI_Total Body Mass Index 1 -.327 ** -.311 **.030 Sig. (1-tailed).000.000.332 N 212 208 211 209 Pearson -.327 ** 1.178 **.099 Correlation Sig. (1-tailed).000.005.078 N 208 208 207 205 Pearson -.311 **.178 ** 1 -.005 Correlation Sig. (1-tailed).000.005.471 N 211 207 211 208 Pearson.030.099 -.005 1 Correlation Sig. (1-tailed).332.078.471 N 209 205 208 209 **. Correlation is significant at the 0.01 level (1-tailed).
Conclusions
Conclusions Vitamin D Deficiency is very prevalent among young Adult Emiratis (both genders). Males have a slightly higher Vitamin D status and a lower avoidance of the sun as compared to females. There is a seasonal variation pattern for Vitamin D status among the participants (being the opposite of what is reported in Western countries).
Conclusions Significant negative correlation between Vitamin D status & SAI Significant negative correlation between Vitamin D status & BDI Significant positive correlation between BDI & SAI X No correlation between Vitamin D and FFQ X No correlation between Vitamin D and BMI
Deliverables Documented the true picture of VTD deficiency among University students in the UAE Guide future intervention studies which would aim at implementing awareness programs to educate people about the beneficial role of VTD (implications from SAI results, advocating for sensible sun exposure) Encourage policy makers to implement a policy in the UAE regarding the need for fortification of drinks and some food items with VTD
What is next? Large study to measure vitamin D status targeting the general adult Emirati population (SKMC-ZU Project) Intervention study among depressed and vitamin D deficient individuals Prevalence and Clinical Implication of hypocalcemia and hypovitaminosis D in ICU patients Prospective study of Vitamin D deficiency and community acquired pneumonia
Acknowledgements Research office (ZU) Emirates Foundation For Philanthropy Shareefa Al Adawi, Mariam Al Mansouri, Mariam Sayar, Azza Ahmad, Sara Hisham Sumaya Al Ameri and GASCO team UV Foundation (McLean, VA)