VITAMIN D STATUS AND DETERMINANTS AMONG AMBULATORY PATIENTS: A CROSS-SECTIONAL STUDY

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1 VITAMIN D STATUS AND DETERMINANTS AMONG AMBULATORY PATIENTS: A CROSS-SECTIONAL STUDY 1 RACHKIDI DIANA, 2 AOUN ANTOINE 1 Departmet of Huma Nutritio ad Dietetics, Holy Spirit Uiversity of Kaslik, Jouieh, Lebao 2 Departmet of Nursig ad Health Scieces, Notre Dame Uiversity, Zouk Mosbeh, Lebao 1 diaa.rachkidi@gmail.com, 2 aaou@du.edu.lb ABSTRACT May reports from the suy Middle East regio have show a cotradictory high prevalece of vitami D deficiecy i differet subgroups. Therefore, a cross-sectioal study was performed to assess vitami D status ad its lifestyle determiats i a sample of Lebaese ambulatory patiets referred by their physicia to test vitami D levels. A total of 105 subjects (87 wome ad 18 me; mea age ± 14.59) years) were recruited from a uiversity hospital (latitude 34 orth) durig a period of 4 moths. Vitami D cocetratios raged from 8 to mol/l with a mea 25-hydroxyvitami D of ± mol/l. The prevalece of deficiecy (<50 mol/l), isufficiecy ( mol/l) ad sufficiecy ( 75 mol/l) were respectively 51.43, 21.9 ad Vitami D itake from food varied betwee 6 ad IU/d (mea itake ± IU/d). Amog the sample, were already takig utritioal supplemets cotaiig vitami D. Moreover, 74.3 of the patiets preseted oe or more symptoms related to vitami D deficiecy, 86.7 had oe or more coditios predisposig to deficiecy ad oly 2.9 did ot show ay symptom or predisposig coditios. I a multiliear regressio aalysis, dietary vitami D itake, supplemet use ad su exposure betwee ad hours were idepedetly predictive of vitami D cocetratios (P< each). I this sample of ambulatory patiets, results show high percetage of vitami D iadequacy ad particular cotributig factors that should be take ito cosideratio whe suspectig vitami D deficiecy i medical practice. Keywords: Vitami D, Patiet, Deficiecy, Dietary itake, Supplemet 1. INTRODUCTION The role of vitami D i promotig boe health is well established (1,2). Serum 25-hydroxyvitami D (25(OH)D) is the major circulatig metabolite, reflectig vitami D stores i the body. Its levels are the best curret idicator of vitami D status (3,4). Cutaeous sythesis through UVB exposure is the mai source of vitami D (5,6). This sythesis is eabled all year roud for latitudes below 37 degrees (7). However, may factors are capable of impairig the edogeous productio of vitami D such as time of the day, age, hyperpigmetatio, suscree use ad clothes (4,8,9). Vitami D ca also be aturally foud i a limited umber of dietary sources such as fatty fish, egg yolk ad irradiated mushrooms, ad obtaied from food fortificatio (6,10,11) which is more commo i developed coutries (12). Over the previous decade, vitami D has received sigificat attetio for its associatio with adverse health outcomes beyod boe disorders, icludig 1 cacer (13), cardiovascular diseases (14), diabetes mellitus (15), autoimmue (16) ad eurodegeerative diseases (17), ad eve mortality (18). Also, vitami D deficiecy has become a major public health cocer meacig may parts of the world (9). Surprisigly, lowest rates of vitami D were observed i Middle-Easter coutries (19,20). Moreover, recet studies reported high prevalece of deficiecy i Lebao. I a populatio of Lebaese osteoporotic wome, 84.9 preseted a iadequate vitami D status (21). I additio, i aother study coducted o healthy schoolchildre, 52 showed a poor status (22). Also this iadequacy was see i 32.8 of Lebaese uiversity studets (23). Due to this alarmig cocer, vitami D testig has become a routie part i may medical practices especially that vitami D iadequacy is hard to recogize cliically. Classic maifestatios of vitami D deficiecy ivolve muscle weakess, myalgia ad boe pai which could also be symptoms of may other medical coditios (24).

2 Curretly, there are o clear guidelies or a reliable algorithm that ca assist physicias i choosig the target populatio for vitami D testig. Thereby, there has bee a otable icrease i serum 25-hydroxyvitami D testig i Lebao, a relatively expesive test. Thus, a easier, cheaper ad efficiet strategy, takig ito accout most importat cotributig factors, should be implemeted to determie the idividuals who eed vitami D testig. The purpose of this study is to examie vitami D status i a populatio of Lebaese patiets referred by their physicia for vitami D testig as a part of a routie check-up. Furthermore, we assessed the role of dietary ad lifestyle factors i predictig vitami D status i order to help physicias scree vitami D iadequacy more efficietly i their practices. 2. MATERIALS AND METHODS 2.1. Participats ad Data Collectio The preset cross-sectioal study was coducted at a Lebaese hospital i Jbeil, Mout Lebao (latitude 34 North). Recruitmet was doe durig sprig-summertime from April to July Participats were selected based o the medical prescriptio sheet whe they arrived at the hospital laboratory for a blood test. Cadidates icluded are all those referred by their persoal physicia to test serum 25(OH)D amog the differet aalyses, ad aged more tha 18 years old. A total of oe hudred ad five outpatiets visited the laboratory for vitami D testig, ad were eligible to participate i the survey after sigig the coset form. The form was approved by the ethics committee of the hospital. Participats were ivited to complete a iterview-assisted questioaire before proceedig to blood drawig. The questioaire was composed of three sectios. The first part sought demographic ad cliical characteristics, icludig sex, age ad BMI (Body Mass Idex) calculated as weight divided by height squared ad the classified ito uderweight (BMI<18.5 kg/m 2 ), ormal weight (18.5 BMI<25 kg/m 2 ), overweight (25 BMI<30 kg/m 2 ) ad obesity (BMI 30 kg/m 2 ). It also covered the medical cotext which icluded past or existig coditios ad diseases related to vitami D deficiecy, curret medicatios, ad sigs 2 associated with hypovitamiosis D. Physical activity level (PAL) as well as alcohol ad smokig habits were idetified. The secod part examied su exposure habits by determiig body parts ormally exposed to sulight (face, hads, arms, legs), suscree use (yes or o aswer), duratio of su exposure calculated i miutes per week, ad the usual time of exposure divided ito three itervals: before hours, betwee ad hours, ad after hours. Fially, i the third part, a food frequecy questioaire was admiistered to calculate vitami D itake. The foods icluded are those cotaiig vitami D ad accessible at the Lebaese market, such as: fortified milk, yogurt, cheese, fortified cereals, whole eggs, salmo, sardies, tua ad butter. Nie resposes optios ragig from "ever or <1 time/moth" to "2 times/day or more" were give. Portios were based o household uits (eg, cup, teaspoo, tablespoo, slice). Similarly, the amout of vitami D itake from supplemets was calculated by idicatig the usage of ay supplemet cotaiig vitami D, the by determiig the frequecy of use ad dosage Vitami D Status Blood samples were collected via veipucture by the hospital phlebotomists. Serum 25(OH)D cocetratios were measured usig electrochemilumiescece immuoassay (Cobas 6000 Aalyzer, Roche Diagostics), a method demostratig a good correlatio with the other assays (25). Results were obtaied i mol/l with a detectio limit <10 mol/l. Based o the defiitio of the America Edocrie Society for vitami D status, vitami D levels were classified ito three categories: Deficiecy, Isufficiecy ad Sufficiecy for values <50 mol/l, betwee 50 ad 74.9 mol/l, ad 75 mol/l, respectively (4). These cut-off values are also used by Lebaese physicias as a way of detectig iadequacy i patiets Statistical Aalysis Statistical aalysis was performed usig SPSS (Statistical Package for Social Scieces) versio Data are preseted as mea ± SD or (). Studet test was used to compare meas betwee the sexes. The associatio betwee vitami D status ad the various variables was ivestigated usig Chi-2 test. Pearso correlatio coefficiets were determied to examie the associatio betwee vitami D levels ad differet variables. A

3 multiliear regressio aalysis was performed i order to study the determiats of 25(OH)D cocetratios. Data were cosidered statistically sigificat for a p-value RESULTS 3.1. Characteristics of Study Populatio Of the 105 subjects, 18 me ad 87 wome participated i the study. Age varied betwee 23 ad 86 with a mea of ± years. Mea BMI was ± 5.25 kg/m 2, with a higher percetage of idividuals havig a ormal weight (41.9), compared to those who were overweight (32.38) or obese (20.95). Serum 25(OH)D levels raged from 8 to with a mea of ± mol/l; o statistical differece was see betwee the sexes (P=0.95). Vitami D itake from food varied cosiderably betwee 6 ad IU/d with a relatively low mea of ± IU/d for all participats. Although the mea was higher i males (91.83 IU/d) tha i females (79.95 IU/d), the differece was o-sigificat (P=0.585). As for the mea su exposure duratio, it was ± miutes per week, therefore approximately 23 mi/d of exposure was see i this populatio; otig that o veiled wome were icluded i the study (Table 1). Amog the cadidates, were takig utritioal supplemets cotaiig vitami D. Moreover, 74.3 had oe or more symptoms related to vitami D deficiecy, icludig: fatigue, boe pai, muscle ache, diarrhea, depressive mood, irritability ad isomia; 86.7 had oe or more coditios predisposig to deficiecy ad oly 2.9 did ot show ay sig or related coditio. Table 1: Characteristics of Study Populatio Total Me Wome Mea SD Mea SD Mea SD P Age (years) BMI (kg/m 2 ) (OH)D (mol/l) Vitami D dietary itake (IU/d) Duratio of su exposure (mi/week) BMI, body mass idex; 25(OH)D, 25-hydroxyvitami D 3.2. Prevalece of Vitami D Deficiecy ad Iadequacy (73.33) suffered from a iadequate or a suboptimal vitami D status (<75 mol/l). Usig vitami D cut-off values, a high prevalece of was deemed as vitami D deficiet (<50 mol/l). Smaller percetages of 21.9 ad had respectively isufficiet ( mol/l) ad sufficiet vitami D status ( 75 mol/l). Thus, the majority of the populatio Associatio Betwee Vitami D Status ad Potetial Cotributig Factors The relatioship betwee vitami D status ad lifestyle factors is preseted i table 2. Amog the differet factors studied, vitami D status seems oly depedet o age, vitami D supplemet use ad su exposure betwee ad hours.

4 However, sex, BMI, physical activity level, alcohol cosumptio, smokig, body parts ormally su exposed, ad suscree use were ot associated with vitami D status. Table 2: Characteristics of Study Populatio ad Associatio Betwee Vitami D Status ad Lifestyle Factors Participats 105 Deficiecy <50 mol/l 54 Isufficiecy mol/l 23 Sufficiecy 75 mol/l Sex Male Female Age (years) < BMI Uderweight Normal Overweight Obese PAL Iactive Low Medium Alcohol cosumptio No Occasioally Daily Smokig No Occasioally Daily Supplemets cotaiig vitami D No Yes Body parts exposed to sulight Face, hads Face, hads, arms Face, hads, arms, legs Su exposure betwee ad hours No Yes Suscree use No Yes BMI, body mass idex; PAL, physical activity level 28 P < < Serum 25(OH)D was sigificatly ad positively correlated with age (r 0.365; P<0.0001) ad strogly correlated with vitami D itake from food ad supplemets (r 0.773; P<0.0001). No variatio 4 was observed with BMI (r ; P=0.516) ad duratio of su exposure (r 0.023; P=0.820).

5 A multiliear regressio was performed i order to assess potetial determiats of vitami D cocetratios. The aalysis is show i table 3. Accordig to the coefficiets table, vitami D itake, supplemet use ad su exposure betwee ad hours were idepedetly predictive of serum 25(OH)D levels (P<0.0001, each). Table 3: Multiliear Regressio Aalysis With Serum 25-Hydroxyvitami D as a Depedet Variable β SE t P Costat < Age (years) Vitami D itake (IU/d) < Supplemets cotaiig vitami D* < Su exposure betwee ad hoursƚ < *Use of supplemets cotaiig vitami D was evaluated as a score; for o vitami D supplemet itake, 0; for vitami D supplemet itake, 1. ƚ For o usual su exposure betwee ad hours, 0; for usual su exposure betwee ad hours, DISCUSSION Vitami D iadequacy has become a widespread problem i the world, reachig vulerable as ovulerable idividuals (26). I our study performed o patiets suspected of havig vitami D deficiecy, the majority (73.33) suffered from less tha a optimal status. These results were expected as differet studies i Lebao showed that, despite the suy weather, vitami D deficiecy is highly prevalet i may subgroups (21-23). It has bee proposed that cutaeous sythesis of vitami D ca be established throughout the year for latitudes below 37 (4,7). As a result, the latitude of Lebao of 34 North is supposed to allow this photoproductio. But i the preset study, the duratio of su exposure did ot affect 25(OH)D cocetratios, showig that the legth of exposure does ot always esure adequate status. This fidig is supported by studies doe i suy coutries. Despite prologed su exposure, it appears that several factors ca affect the cutaeous sythesis ad bioavailability of vitami D produced, icludig: impaired cutaeous productio, icreased cutaeous destructio of previtami D ad vitami D, decreased sythesis iduced by melai productio, or a problem i the trasport of vitami D (27,28). I additio, it is plausible that geetic differeces, havig a crucial effect o the determiatio of vitami D status, could exist betwee idividuals (29,30). 5 Although a associatio betwee duratio of su exposure ad vitami D levels was ot see, a usual exposure to sulight aroud oo was associated with a better vitami D status, supportig proposed theories (4,7). But these hours betwee ad are cosidered the most dagerous ad ski damagig, exposig idividuals to a higher risk of ski cacer ad several other health problems (31). Moreover, i our study, a higher percetage of participats exposig themselves i this time period had a isufficiet status. Hece, it seems that geophysical parameters play a major role i determiig the amout of UVB photos reachig the ski, ad therefore determiig vitami D status. These parameters iclude the variatio i cloud cover, pollutio, surface ad altitude (8). Furthermore, UVB rays could also be blocked by dress code ad suscree applicatio (9). However, we foud that vitami D status was ot associated with body parts ormally exposed to sulight ad suscree use. Due to a decreased cutaeous sythesis ad real activatio of vitami D, a low dietary itake, ad a limited su exposure, older age is usually liked to a poor vitami D status (32). Iterestigly, i the curret study, a positive ad sigificat correlatio was observed betwee serum 25(OH)D ad age. This observatio could be explaied by a icreased systematic prescriptio of supplemets cotaiig vitami D, especially i the elderly. I fact, age, as a idepedet factor, had o effect o the variatio of vitami D levels after takig ito accout supplemet itake. Similarly, serum

6 25(OH)D was ot affected by BMI, despite the fact that vitami D is a fat soluble vitami ad is sequestered i adipose tissue, reducig its bioavailability i obese ad overweight idividuals (33). However, BMI does ot always reflect the percetage of body fat. I additio, the distributio of body fat may also play a role i vitami D bioavailability. Thus, the subcutaeous fat ca store more vitami D sythesized i the ski tha that obtaied from diet ad supplemets (34). As expected, serum 25(OH)D levels were sigificatly correlated to vitami D itake from food ad supplemets. However, vitami D itake from food oly was very low compared to the recet recommedatios of 600 IU for adults ad 800 IU for elderly (35), a dose capable of maitaiig a vitami D level above 50 mol/l. These low itakes could be explaied by the limited umber of foods aturally rich i vitami D ad the lack of Lebaese regulatios allowig the fortificatio of certai foods ad beverages actually fortified i developed coutries. Despite the cotroversy surroudig the cut-off values of vitami D, a value greater tha 75 mol/l is the desirable level recommeded by experts ad physicias to prevet chroic diseases (36), as supported by the moutig epidemiological evidece. Ad the, i order to icrease ad maitai serum levels above this value, a safe itake of 1500 to 2000 IU/d is required (4), especially i case of low su exposure. I our study, supplemets were the oly way to esure a optimal vitami D status, ad therefore able to provide the itake eeded to maitai skeletal ad extra-skeletal health. Certai limitatios should be oted. Vitami D itake was calculated usig a frequecy questioaire, thus a error i the estimatio of the portio cosumed ad frequecy of cosumptio may exist. I additio, the data collected were selfreported. I coclusio, vitami D itake from food ad supplemets as well as usual su exposure aroud oo reported to be the best idicators of vitami D levels ad status. Thereby, takig these factors ito cosideratio could assist physicias i determiig vitami D status ad assessig whether patiets eed a serum 25(OH)D testig. Furthermore, prescribig vitami D supplemets systematically should be cosidered, especially i coutries with limited food fortificatio. Ad eve a efficiet but safe su exposure could be recosidered. 5. REFERENCES 1. Rizzoli R, Booe S, Bradi ML et al. The role of calcium ad vitami D i the maagemet of osteoporosis. Boe. 2008;42: Holick MF. The vitami D deficiecy pademic: a forgotte hormoe importat for health. Public Health Reviews. 2010;32: Wolpowitz D & Gilchrest BA. The vitami D questios: How much do you eed ad how should you get it? J Am Acad Dermatol. 2006;54: Holick MF, Bikley NC, Bischoff-Ferrari HA et al. Evaluatio, treatmet, ad prevetio of vitami D deficiecy: a edocrie society cliical practice guidelie. J Cli Edocriol Metab. 2011;96: Dobig H. A review of the health cosequeces of the vitami D deficiecy pademic. J Neurol Sci. 2011;311: Cashma KD & Kiely M. Recommeded dietary itakes for vitami D: where do they come from, what do they achieve ad how ca we meet them? J Hum Nutr Diet. 2014;27: Grat WB & Holick MF. Beefits ad requiremets of vitami D for optimal health: A review. Alter Med Rev. 2005;10: Egelse O. The relatioship betwee ultraviolet radiatio exposure ad vitami D status. Nutriets. 2010;2: Tsiaras WG & Weistock MA. Factors ifluecig vitami D status. Acta Derm Veereol. 2011;91: Pearce SH & Cheetham TD. Diagosis ad maagemet of vitami D deficiecy. Br Med J. 2010;340: Gilaberte Y, Aguilera J, Carrascosa JM et al. Vitami D: evidece ad cotroversies. Actas Dermosifiliogr. 2011;102: Holick MF, Biacuzzo RM, Che TC et al. Vitami D2 is as effective as vitami D3 i maitaiig circulatig cocetratios of 25-hydroxyvitami D. J Cli Edocriol Metab. 2008;93: Welsh J. Cellular ad molecular effects of vitami D o carciogeesis. Biochem Biophys. 2012;523:

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