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  Vitamin D Status and Some Related Factors Among A Sample of Female
Living in Rural Area of Sharkia Governorate
  Amal Ahmed El Badawy, Shereen Eassa , Ghada M. Ghalil ,Aml Fathy*
Community Medicine,Biochemistry Departments,Faculty Of Medicine Zagazig
 
    ABSTRACT  
  INTRODUCTIN  
  SUBJECTS AND METHODS  
  RESULT  
  DISCUSSTION  
  REFEREENCES  

 
    ABSTRACT
Back ground: Vitamin D is known to be essential for bone health. it is acquired through dietary intake and skin exposure to ultraviolet B light. Prevalence of vitamin D differ greatly between countries. Different factors may affect level of vitamin D such as personal, socio-biological and nutritional factors.
Objectives:male in childbearing period through the following objectives :
1-Estimate the level of vit D among a group of female in childbearing period in rural area at Sharkia Governorates.
2-Identify the role of different risk factors to be associated with vitamin D problem such as exposure to sun light (time and duration),some lifestyle habits as style of clothes, socio-biological factors and dietary intake of vit D.
3- Estimate the association between vit D level and some minerals and hormones like Ca ,Ph ,bone specific alkaline phosphatase and parathormone hormone .
Methods: A cluster of females of childbearing period from 2 villages in Sharkia Governorate were included in the study. They were subjected to interview and a pretested questionnaire was used including data about socio-biological characteristics, some aspect of their diet, history of medical condition, drug intake, exposure to sunlight. Blood tests were carried out for detection of vitamin D level, calcium, phosphorus, parathormon and serum alkaline phosphatase.
Results: the percentage of vitamin D insufficiency was 80.6 %. The risk of vit D insuffiency was significant higher among dark pigmented skin female (OR 2.27), not working (OR 1.87),lack of exposure to sun light (OR 4.5), those who expose only their face (OR 3.83),taking less than I cup of milk per day and eating less than l meal per week of salmon and sardine(OR 3.69,1.95 respectively ). Also those who complained from bony ache had a risk about 2 times higher than those with normal level of vit D. After doing serological investigations, the percentage of vitamin D insufficiency is only significant higher among those with low calcium level.
Conclusion and recommendations: The results of this study suggested that examined females are at high risk of vit D insufficiency and this attributed to insufficient sunlight exposure and low dietary vit D intake, so there is a need to take public health measures to improve vit D status through wide spread vitamin D supplementation, modest skin sunshine exposure, increase food fortification with vit D and an awareness among public and physicians on the urgent need to improve vitamin D intake .
Key word: vit D, prevalence, risk factors, sun light exposure, metabolism
 
 
   INTRODUCTIN
  ** Vitamin D is not really vitamin but a neurohormon that is important for calcium metabolism ,bone growth, immune function and brain development (1). Our bodies produce vitamin D in response to sunlight (UVB radiation), but areas of the world north of latitude 30 north as San Diego (USA) or Cairo (Egypt), may not get enough sun during September through May to provide adequate vitamin D levels (2)
** The prevalence of vit D deficiency greatly different between countries ,it was 36% in Iranian postmenopausal women and 36 %% among the general Saudi Arabian population . But in North America , owing to oral vitamin D intake, hypovitaminosis D is rarely, if ever, reported in healthy young adults. In Scandinavian countries, vitamin D deficiency has been reported in about 4%–9% of young adults during winter, and in up to 5% during summer(3,4).
** In Egypt , Hassan et al 2004 reported the prevalence of vit D among age group 11-19 years about 4% and among those above 20 years about 3 % with no significant difference between male and female (5)
** Because of the concern about skin damage and cancer when exposed to ultraviolet radiation above 3 [ultraviolet radiation divided into different levels : low (1-2) ,moderate (3-5 ),high (6-7 ), very high (8-10 ) and extreme (11 and above ) ] ,many may have avoided direct sun exposure and they depend on dietary sources for vit D requirement. (6) Most diet are low in vit D and among richest foods with vitamin D ( provided more than 15 % of daily value percent )oily fish such as code liver oil ,salmon, mackerel ,tuna fish ,sardines ,milk and margarine (7).
** The current recommendation for adult intake of vitamin D is 400 IU per day, but other study suggested that a vitamin D intake of 600 IU was insufficient to maintain adequate vitamin D levels in the body in the absence of sun exposure and proposed an increase of the minimum daily recommended adult dose to 1,000 IU per day (2)
** People with darker pigmentation or keratinization causing darker coloured skin have decreased sunlight penetrating to the deeper layer of the skin where vit D is produced (8).
** Others populations at risk of deficiency included :those with decreased sun exposure because of lack of time spent outdoors "(an increasing common situation in developed setting ),those covered extensively by clothing ,as seen most profoundly in women observing purdah ,those with gut absorption problems or who have a diet deficient in vit D ( 9,10). Exposing face ,arms, hands to the sun for 10 minutes in summer ,15-20 minutes in spring and autumn and 30 minutes in winter, outside peak UV times should give enough vit D .But people with darker skin needed up to 2.5 hours of sun exposure per day to supply enough vitamin D (6).
** Vitamin D (where D represents D2 or D3) is biologically inert and metabolized in the liver to 25-hydroxyvitamin D [25(OH)D], which is activated in the kidneys to 1,25-dihydroxyvitamin D [1,25(OH)2D], that regulates calcium, phosphorus, and bone metabolism.(11)
** It is believed that reduced capability of the kidney to synthesize 1,25-dihydroxyvitamin D [1,25-(OH)2D] are responsible for impairment in dietary calcium absorption. These deficits lead to compensatory hypersecretion of parathyroid hormone, which results in bone loss . The serum level of 25-hydroxyvitamin D (25-OHD) has been accepted as an index for vitamin D status (7,11).
** Deficiency of vit D most commonly presented asymptomatic. However, it may also present as osteoporosis or its complications, particularly in postmenopausal women and the elderly .infants of women who are vit D deficient during pregnancy will usually also be vitamin D deficient and hence at an increased risk of both short and long term sequel. In addition to the well established dysfunction of bone and muscle metabolism ,vit D has been linked with a wide range of other illness such as diabetes ,schizophrenia ,prostate cancer ,multiple scelerosis and autoimmune disorders.(12) Therefore it is important to assess serum vit D levels for early detection of deficiency and provide adequate treatment to avoid the catastrophic complications.
1 - Estimate the level of vit D among a group of female in childbearing period in rural area at Sharkia Governorate .
2 -Identify the role of different risk factors to be associated with vitamin D problem such as exposure to sun light (time and duration),some lifestyle habits as style of clothes, sociobiological factors and dietary intake of vit D.
3 -Estimate the association between vit D level and some minerals and hormones like Ca ,Ph ,bone specific alkaline phosphatase and parathormone hormone .
 

  SUBJECTS AND METHODS
  This study was a screening survey conducted in Sharkia governorate 2006 to assess the problem of vit D deficiency among a cluster sample of female in childbearing period with the support and funded from Egyptian Society of Osteoporosis in Egypt . El Robemaia and Tahrt Hemida villages were randomly selected and every village was divided into four clusters by using specific landmarks , and cluster from each village was randomly selected. All available female in childbearing period in the selected cluster were included in the study. to yield the desired number of our sample.
** With the co-operation of non governmental organization ,notification was done to motivate people to participate in our work and providing them with special beneficial things to them .

Sample size: Assuming that the estimated prevalence is about 20 % at confidence level of 95% and degree of precision of 80% , and the total number of female in childbearing period was 973172 , accounting for a drop out rate of 10% , the sample size was estimated to be 423 females.
 
Data collection : using a pre-designed questionnaire after testing it by doing a pilot study on about 45 females
A questionnaire was used to collect information ,regarding.
1)Sociobiological data about age, marital status , occupation and parity.
2) Exposure to daily sunlight : Either exposure occurs due to exposure outside her house only or sun rays enter the house. Exposure time :either before 10 am or from 10 to 2 pm or after 2 pm Periodic of exposure if every day ,or alternative day or every 3 or 4 days Duration of exposure in each season if less than 10 minute ,10-30 min or more than 30 minute
3) Personal criteria : colour of skin (either dark, average or light),wearing veil or not and parts of her body exposed to sun (face only or face , her hands and arms)
4) Medical condition if there is history of any medical diseases , history of drug intake or history of bony ache and fracture .
5) Special habits : doing physical activity (like walking ) and smoking.
6) Types of diet : if her diet include milk 9number of cups per week ,egg , beef liver, sardine, salmon ,tuna the amount calculated per week according to ( 13)
Investigations consent for testing was be taken after providing person with information regarding test procedures, meaning of test results, and the benefit of early detection. The values of serum calcium, phosphorous and alkaline phosphates were done by colometric methods, 25-OH was done by HPLC methods and parathormon hormone by immunoassay in vitro nodular analytics E170. we intend to follow up the groups who have low values and provide them with drugs later on in the next research and apply preventive intervention action.
Statistical analysis : the collected data was coded and analyzed using SPSS version 11 ,statistical package for social science (1998) (14).
Ethical consideration : Before the interview, an orientation about the objectives of the study was carried out, followed by verbal consent taken from every interviewee. Confidentiality was maintained through the study.

   RESULT
Table (1) A: Percentage of Vit D Level Among the sample group According to The Laboratory Results:
 
Variables Percentages
 
    Normal level of vit D ( ≥40 nmol /L) 19.4 %
    Vit D insufficiency ( < 40 nmol /L): 880.6 %
         -Vitamine D deficiency <25 nmol/L 42.6 %

   -Hypovitaminosis D 25-40 nmol/L

38.0 %
     
     
Table (1) B: percentages of Vit D Level According to Ringer S Classification:
 
Variables Percentages
 
     Normal level ( ≥ 30 nmol/L) 39.9 %
    Vit D insuffiency ( <30 nmol/L ) 60.1 %
         -Vit.D deficiency (<15 nmol/l) 18.0 %

   -Hypovitaminosis D (15-30 nmol/l)

42.1 %
     
     
Table (2) Association Between Vit D Level and Some Personal and Socio-biological Characteristics:
 
Variables Vit D insufficiency Normal level of vit D OR 95 %CI
 
  Age:
 More than 40 years
81.3 % 18.7 % 1.08 0.63-1.86
  Marital Status -      
 Married
81.6 % 18.5 % 1.3 0.75-2.39
   Parity -More than 3
  children
81.2 % 18.8 % 1.09 0.6-1.82
  Occupation: Not
  working
87.0 % 13.0 % 1.87 1.06-3.31*
   Colour of skin - 
  Average or dark. -
  Light.
85.3 %
71.9 %
14.7 %
28.1 %
2.27 1.19-4.35*
   Clothing status
  Veiled
  Not veiled
80.7 %
83.3
19.3 %
16.7 %
.83 0.12-4.142
     
  * indicate significant ( p<0.05)  
  **OR = Odds Ratio  
  **CI = Confidence Interval  
     
     
     
Table ( 3 ) Association Between Vit D Level and Some Lifestyle Habits :
 
Variables Vit D insufficiency Normal level of vit D OR 95 %CI
 
   Lack exposure to sun 
  through : -
  Going Outdoor
  -In the House 
79.5 %
81.05 %
20.5 %
19.0 %
4.50
1.21
2.00-10.39* 0.57-2.57
   Exposure to sun less
  than 30 minute
  Winter
  Spring and autumn
  Summer
82.6 %
83.4 %
78.6 %
17.4 %
16.6 %
21.4 %
1.2
1.3
0.83
0.70-2.0 0.80-2.2 0.83-1.3
   Parts of the body
  exposed to sun
  More Than the face 
  Face
59.6 %
85.0 %
40.4 %
15.0 %
3.83 2.32-6.32*
  Doing physical activity 76.6 % 23.4 % 0.89 0.46-1.75
     
     
     
Table ( 4 )Association Between Vit D Level and Nutritional Habits :
 
Variables Vit D insufficiency Normal level of vit D OR 95 %CI
 
   Less than 1 cup of
  milk /day (100 IU)***
85.0 % 15.0 % 3.69 2.05-6.63*
   less than 1 egg /day
  (25 IU)
75.5 % 24.5 % 3.08 0.31-31.02
   Beef liver less than 1
  meal / week (30 IU)
80.3 % 19.7 % .93 0.4-1.8
   Salmon and sardine
 less than1 meal / week
 (270 IU)
81.9 % 18.9 % 1.95 1.1-3.97*
     
  ***IU : international unite  
     
     
     
Table (5) Association Between Vit D Level and Medical History :
 
Variables Vit D insufficiency Normal level of vit D OR 95 %CI
 
   Taking medication 87.5 % 12.5 % 5.39 0.71-4.69
   Complaining of bony
  ache.
83.7 % 16.3 % 2.15 1.21 -3.79*
   Previous exposure to
  fracture.
78.1 % 21.9 % .90 0.51 -1.61
     
     
     
Table (6) Association Between Vit D Level and Some Laboratory Investigations:
 
Variables Vit D insufficiency Normal level of vit D OR 95 %CI
 
    Ca deficiency 81.5 % 18.5 % 3.58 1.54-8.3*
   Alkaline
  phosphotase
  deficiency
81.3 % 18.7 .3 0.07-1.2
   Parathormon  
  hormone deficiency
84.3 % 15.7 1.69 0.5-5.19
   Phosphorous 
  deficiency
64.7 % 35.3 .13 0.83-1.04
     
     
     

  DISCUSSTION
  ** The normal or physiological range of serum 25 –OHD is controversial and it is difficult to be defined, as the values proved to differ considerably between individuals , age groups, and populations. In general, the lower limit of normal range (hypovitaminosis D ) is defined as serum 25-OHD concentration less than 25-37 nmol/L. However , a higher cutoff level of serum 25-OHD concentration (< 50 nmol/L)has been suggested based on a recent physiologic study of the threshold serum 25-OHD concentrations required to maintain normal serum concentrations required to maintain normal serum concentrations of parathormon hormone in adults. Some experts suggest that levels as high as 75 nmol/L may be necessary to optimize bone health ,whereas others suggest 50 nmol/L has therapeutic target (15).br />
** Also , increasing cutoff point increase the sensitivity of the test to detect a higher proportion of those with hypovitaminosis and a preventive measures can be applied to those group to decrease the incidence of vit D deficiency and its complications.

** Cumulative percentages of vit D insufficiency (25-OHD < 40 nmol/L) among our study population was 80.1 % and percentage of vit D deficiency ( 25-OHD <25 nmol /L) was 42.0 % according to our laboratory cutoff point. According to ringer  s classification cumulative percentages of hypovitaminosis (25-OHS <30 nmol /L was 42.1 % and percentage of vit D deficiency was 18.0 %. Table (1)

** A number of studies also revealed a higher levels of hypovitaminosis D , in Lebanon hypovitaminosis D (25 OHD <30 nmol/L) affected 72 % of the study population. Among Saudi women, hypovitaminosis D (25 OHD <30 nmol/L) affected 30.7 % and a study to detect relationship between bone mineral density and vit D status revealed that about 52 % of the subjects had sever hypovitaminosis D (25-OHD levels <20 nmol/L ) (16,17). A study in United Arab Emirates reported a prevalence of vit D deficiency (serum 25 OHD concentration <12.5 nmol/L ) as 24 % among UAE nationals and 12% in non Gulf Arabs and non of the Europeans living in this area had serum 25-OHD concentrations less than 50 nmol /L . In a more recent study ,nearly all the subjects of the study in UAE had serum 25 –OHD concentrations lower than 50 nmol/L. Studies from Turkey, Iran and Pakistan ,have also demonstrated a high prevalence of hypovitaminosis D and vit deficiency in Middle Eastern women.(18,19).

** In agreeing with Gannage et 2000(16), the risk of vit D insuffiency increase and it was higher among older female above 40 years, married women and those who have more than 3 children but without significant evidence while those who not working had a significant higher risk about two times more than those who working ,this may be due to low level of exposure to sun rays which convert vit D into active form, also educational level among not working female may affect nutritional knowledge and habits.(table2)

** Studying the relationship between vit D level and some lifestyle habits indicated that  among women, lack exposure to sun through going outdoor only 2 for 3 times per week  had 4 times higher risk of developing vit D insufficiency (OR 4.57  CI 2.5-10.39  ) (table3). This result is consistant with Dawodu et al 1998 (15) as they found a positive correlation r=0.59 between serum 25-OHD and exposure to UV sun score ,also Glerup et al 2000(2) found sever vit D deficiency among those deprived exposure to sunlight. Islam and his colleagues 2006(20) reported that increasing time spent outdoor associated with significant increase in serum 25-OHD, this is consistant with our results as we found a higher percentage of vit d insuffiency  among those who spent less than 30 minutes outdoor exposed to sun rays during winter ,spring and autumn .

** Although many studies incrime clothing status as wearing veil with vit D deficiency (2,16,21 ) and we found a higher percentage of vit D insufficiency among veiled 80.7 % but without statistical significant (table2) and this is in consistant with Guzel and his colleague 2001(22) as they found non of the veiled women had vit D insufficiency but they have lower values of vit D than that among the control.

** To get enough vitamin D, you need only to expose about 15 %of your body such as face hands and arms (6 ), this is agreeing with our results as the risk of vit D insuffiency increased among those who not exposed to sun rays or expose only their face than those who expose their face ,hand and arm (either exposed inside their houses or on going outdoor). (table3) (OR =3.83 CI=2.32-6.32 )

** Not only the parts of the body exposed to sun but also colour of the skin have a significant role among our sample ,average or dark colour of the skin had a significant risk of developing vit D insufficiency (OR=2.27 CI= 1.19-4.35) (table2).This finding was recorded as people with darker skin have decreased sunlight penetrating to the deeper layer of the skin where vit D produced, so dark skinned individuals demand a far higher dose of UV-B to reach the maximum cutaneous vit D production .(23)

** Also duration of exposure affected with the colour of the skin as previtamin D concentration in the skin reaches equilibrium in white skin within 20 minutes of UV exposure, whereas it takes 3-6 times longer in pigmented skin.(24).

** As regard to medical history we found those with history of taking previous medication ,complaining of bony ache and previous exposure to fracture had higher percentage of vit D insufficiency (87.5, 83.7, 78.1% respectively), but only those who complaining of bony ache had a significant association (OR 2.15& CI 1.21-3.79) . Although, this finding is less well known ,but it is well established as the prevalence of musculoskeletal pain and weakness increase with vit D insufficiency . Some may attributed this to the role of vit D deficiency in causing osteomalacia which is associated with nonspecific isolated or generalized bone pain ,muscle aches and muscle weakness. In one study of Danish women of Arab who presented with muscle pain and weakness ,they were found to have sever vit D deficiency and osteomalacia.(2). (table5)

** Although, the adequate intake for vitamin D as recommended by the Institute of Medicine is 200,400,and 600 IU of vit D for ages up to 71 years, several studies reported that such intake is not sufficient and at least 800-1000 IU of vit D intake is required to prevent vit D deficiency. In a study among Lebanese, the average dietary intake of vit D was 100 IU ,and in generally, Arab women lack adequate intake of vitamin D. (24). Only few food such as fatty fish, fish oil, fortified food such as milk margarine and oil naturally contain significant amount of vit D(7) . In our study , hypovitaminosis is significant higher among those who take less than 1cup of milk per day ( less than 100 IU of vit D ) and eating less than 1 meal per week of salmon and sardine about 100gm (contain 270 IU of vit D)(OR 3.69,1.95 &CI 2.05-6.63 ,1.1-3.97 respectively).(table4)

** Serum levels of 25 OH-D were used as estimates of vitamin D status, it is transported to the kidney and hydroxylated to 1,25 dihydroxyvitamine D which play a major role in calcium and phosphorus homeostasis and bone mineralization. So hypovitaminosis D affect levels of ca and phosphorous in the blood and also associated with increasing PTH level (15). In an epidemiological study, a high incidence of vitamin D insufficiency was proved in elderly women and is associated with biochemical signs of increasing bone turnover. Maintenance of parathormon hormone within normal range by vitamin D and calcium supplementation might constitute an important approach for the prevention of bone loss.(7) Among our laboratory results only there is a significant higher risk more than 3 times among those with low serum Ca level than those who have normal level (OR=3.58 &CI 1.54-8.3 ). (table 6)
 
CONCLUSION AND RECOMMENDATIONVit D insufficiency seem to be public health problem among female of childbearing period living in rural area of Sharkia governorates , this is attributed to insufficient sunlight exposure and low dietary vit D intake, so there is a need to take public health measures to improve vit D status through wide spread vitamin D supplementation, modest skin sunshine exposure, increase food fortification with vit D and an awareness among public and physicians on the urgent need to improve vitamin D intake . As many females are occasionally expose their face , arm and hand to direct sunlight thus the daily oral intake should be reach its upper limit 800 IU and future research should focus on appropriate daily dietary vitamin D intake that will prevent hypovitaminosis D if sunshine exposure is limited.

** ** Lack of standardized definition of hypovitaminosis D or vit D deficiency and community based data prevent meaningful international comparison of the magnitude of the problem. Community based studies using a generally accepted definition are urgently needed to provide base line data with which the researchers can evaluate the impact of future interventions on the prevalence of vitamin D deficiency .
ACKNOWLEDGMENT This work was financially supported by Egyptian Society of Osteoporosis in Egypt .the team of work produce their grateful thanks to Pr. Dr Samir Ahmed El-Badawy and other members of the Egyptian Society of Osteoporosis for their support. Also deep thank to NGO and all the team whohelp us in collection of data and finally the participant who give us rapid and unexpected consent to cooperate with us.
 
 
     
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