ORIGINAL ARTICLE Prevalence of Vitamin D Deficiency among Postpartum Women and their Newborns: a cross-sectional study in Karachi, Pakistan

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1 ORIGINAL ARTICLE Prevalence of Vitamin D Deficiency among Postpartum Women and their Newborns: a cross-sectional study in Karachi, Pakistan Syed Tahir Ali, Kaniz Zehra Naqvi, Madiha Maqsood, Savita Thontia 41 Abstract: Background: Vitamin D deficiency during pregnancy has been linked with number of serious short and long term health problems in offspring, therefore adequate maternal vitamin D levels are pivotal for neonatal calcium hemostasis. The objective of this study is to evaluate vitamin D deficiency among post-partum women and their newborns. Methodology: 360 pregnant women were enrolled from Liaquat National Hospital. Serum levels of 25-hydroxyvitamin D3 were assayed in maternal and cord blood samples collected at the time of delivery. Results: The prevalence of vitamin D deficiency in maternal and cord blood was 69.6% and 58.2% respectively. There was significant correlation between maternal and cord blood serum concentration of Vitamin D3. In mothers who were deficient in Vitamin D3, cord blood Vitamin D3 levels were lower than those from normal mothers. (P=.001). A significant direct correlation was also found between parda/veil observers mothers and levels of Vitamin D3 (P<0.002). Conclusion: keeping in view the high prevalence of vitamin D deficiency, considerations should be made for its supplementation in antenatal period to prevent hypovitaminosis in both mother and baby. Keywords: 25-Hydroxyvitamin D3, Hypocalcaemia, Cord blood serum D3 level Liaquat National Hospital and Medical Collage Karachi ST Ali KZ Naqvi M Maqsood S Thontia Correspondence: Dr. Syed Tahir Ali Consultant Paediatrician Liaquat National Hospital and Medical Collage Karachi Cell # hiali76@hotmail. com Pak J Surg 2013; 29(1):41-45 Background: It has been estimated that 1 billion people worldwide have vitamin D deficiency or insuffi c i e n c y. 1,2,3,4 Vitamin D deficiency is defined as a 25-hydroxyvitamin D levels of less than 30 ng/ ml. 1,5 Vitamin D deficiency during pregnancy has been linked with number of serious short and long term health problems in offspring, including impaired growth, skeletal problems, type 1 diabetes, asthma and schizophrenia 6 yet few have explored the role of maternal vitamin D status and pregnancy outcomes. Studies have shown the prevalence of vitamin D deficiency to be 63.3% in pregnant women. 8 Low levels of vitamin D during pregnancy or breast feeding can have an adverse effect on baby s growth, the formation of tooth enamel and the way body handles calcium. 7 It can also put a baby at risk of being born with rickets or developing rickets in childhood. Infants born to mothers with hypovitaminosis D have increased risk of symptomatic hypocalcaemia, small for gestational age and larger fontanelle, suggestive of impaired ossification of skull bones. 8 Reduction in maternal bone density especially in third trimester is a major cause of backache and leg cramps. 9 It also appears that sufficient vitamin D in early life may decrease the risk of health problems later in life such as asthma, wheeze, 10,11 respiratory disorders, 12 multiple sclerosis, 13 risk of cardiovascular diseases, 14 preeclampsia, 15 schizophrenia 16 and autoimmune disease like diabetes mellitus type1. 5,17

2 42 NICE guidelines National Institute for Health and Clinical Excellence, UK states that it is important to maintain adequate vitamin D during pregnancy and breast feeding, and that woman may choose to take up 10 micrograms of vitamin D during this period, particularly if they have specific risk factors (like veil observer, inborn errors of metabolism) for vitamin D deficiency. Hence the aim of the study was to determine the prevalence of vitamin D deficiency in mothers and their newborns. Methodology: This cross sectional study was conducted in Department of Obstetrics & Gynaecology, Liaquat National Hospital from 1st January, 2011 to 31st January, 2012, recruiting 360 pregnant women. After taking informed consent, blood samples were drawn immediately after delivery from mother and cord blood was collected and both were sent to Biochemistry laboratory, Liaquat National Hospital for estimation of vitamin D levels. Ethical approval was obtained from ethical and research committee of Liaquat National Hospital. Subjects were healthy pregnant women and their new born. We excluded females with chronic diseases like renal tubular disease, pre-existing diabetes mellitus or gestational diabetes, sssential hypertension or pregnancy induced hypertension, thyroid diseases, asthmatic and those on supplemental vitamin D or anti-epileptic medications. Electrochemillumenscence technique was used to measure maternal and cord blood vitamin D levels, involving Elecsys 2010 instrument (Roche) Newborns anthropometric measurements were performed at birth using standardized scales. Sample size and sampling technique was a non probability purposive sampling. Sample size was calculated by using WHO sample size determination software with 63.3% prevalence of vitamin D deficiency in pregnant females with 95% confidence interval and 5% level of precision with ST Ali, KZ Naqvi, M Maqsood, S Thontia inflated for non response. Hence we enrolled 360 pregnant females in this study. Data was collected on a specially designed proforma containing the demographic information like age, parity, parda observation, gestational age, and birth weights. Categorical variables like veil/parda and maternal and babies vitamin D levels are presented as frequencies and percentages. Continuous variables like age and BMI are expressed as Means +S.D. Chi-square test was used to see significant difference between serum level of mother with respect to veil/parda and babies serum levels. P-value of <0.05 was considered as statistically significant. All data were entered and analysed through statistical package SPSS version 19. Results: A total of 360 maternal blood and cord blood samples were collected, out of these 11 samples were discarded as the blood was haemolysed, so a total of 349 samples were included. The demographic characteristics of the 349 patients are shown in Table 1. Most women were between 21 and 30 years of age (mean 28.52±3.4 yrs.) the average parity was 1.13±1.1. The women s mean body mass index (calculated as weight in kilograms over height in meter square) was 23.98±2.7. Vitamin D deficiency was found in 243 (69.6%) of mothers with mean levels of 27.33ng/ml. Out of 349 women 146 (41.8%) were veil/parda observer while 203 (58.17%) were non veil/parda observer. Vitamin D deficiency was more common in parda/veil observer females 115 (78.8%) of veil/ parda observer females were deficient in vitamin D as compared to 128 (63.1%) of non-parda observing females. Inadequate exposure to sunlight was found to be a risk factor for vitamin D deficiency, p-value Vitamin D deficiency was also seen in neonates, 203 (58.2%) were found to be deficient. The mean level of vitamin D was ng/ml +7.0.

3 Prevalence of Vitamin D Deficiency among Postpartum Women and their Newborns: a cross-sectional study in Karachi, Pakistan Table 1: Demographic Data Variable: Age in years < >30 Parity Primi >4 BMI < >30 Out of 203 neonates found to be deficient in vitamin D 155 (63.8%) were born to mothers who were themselves deficient in vitamin D, p- value % CI table 2. In our study 58.2% of the babies were found deficient in vitamin D. Vitamin D deficiency was affecting both genders. There was no statistically significant difference between males and females. There was no statistically significant difference between birth weights and vitamin D levels of neonates in our study. Babies with birth weight equal to or >2.5kgs were also equally effected. Therefore we can say that although 94% (324) neonates in our study were more than 2.5kgs, still 197 (60.8%) were found to be deficient in vitamin D3 i,e babies with birth weight >2.5 kg were not having any protective effect on vitamin D deficiency. Length and fronto-occipital circumference have no statistically significant association with vitamin D deficiency. Both appropriate for gestational age length and frontooccipital circumference therefore has no protective effect on vitamin D deficiency in our study. Discussion: There is limited data available in Pakistan about No. of women Table 2: Maternal & Cord Blood Levels of Vitamin D Maternal Levels Cord Levels ng/ml < 30 ng/ml > 30 ng/ml < 30 (n=243) 115 (63.8%) 88 (36.2%) > 30 (n=106) 48 (45.3%) 58 (54.7%) There was positive correlation between maternal & cord blood Vitamin D levels. (P-value <0.001) 43 breast feeding mothers and their babies 19,20 but no study with substantial number of participants is available regarding the status of Vitamin D in pregnant population of Pakistan. Keeping in view the long term effect of its deficiency in both pregnant females and their babies, 21 a study was conducted to see the prevalence of Vitamin. D deficiency in mothers and their newborns The only reason for the exclusion criteria was that certain diseases might have effect on the levels of Vitamin D. The prevalence of vitamin D deficiency found in our study is quite high 69.9%. Similar results were reported from different areas by others authors. 22,23,24,25 This prevalence is reported based on an old definition of vitamin D deficiency,and many investigators describe deficiency as <32ng/ ml. 27,28 A total of 203 (58.2%) babies were also found to be lacking in vitamin D and out of these 155 (63.8%) babies were born to mothers who were themselves deficient in vitamin D. Like other authors 22,23 we also reported strong correlation between vitamin D levels in maternal and cord blood. Vitamin D deficiency not only has implication on the health of women but also adversely effect their babies. Majority of Pakistani females breast feed their babies. When we started collecting the data we did not expect a high prevalance of vitamin D deficiency in our population. As Vitamin D is a sunshine vitamin and Karachi being a tropical city with abundant sunshine and little seasonal variation. In our study we had 41.1% females who were parda observer and 78.8% of these females were lacking in adequate level of vitamin D (P value CI 95%). Parda/veil or lack of exposure to sun, because of more time spent indoors has also been mentioned in other studies as well. 23 But in one study from Tehran they found no difference in clothing habits of vitamin D deficient group and normal group. 26

4 44 In the present study 60.8% of the babies were found deficient in vitamin D. Vitamin D deficiency was affecting both genders. There was no statistically significant difference between males and females. There was no statistically significant difference between birth weights, frontooccipital circumference and vitamin D levels of neonates in our study. Large scale interventional studies are warranted in vitamin D deficit women to look into the impact of vitamin D supplements during pregnancy & its effect on the new born. Conclusion: Vitamin D deficiency is rampant in our region and is an important contributor to disease burden. The high prevalence of vitamin D deficiency in newborn infants calls for Imperative measures because it is not only reflecting hypovitaminosis in babies but also in their mothers. Breast fed and partially breast fed infants should be supplemented with 400 IU/day of vitamin D beginning in first few days of life. Although sun exposure of at least 30 minutes per day provides adequate vitamin D, majority would agree with AAP guidelines for minimizing sun exposure owing to the risk of various skin cancers. In following these guidelines, vitamin D supplementation is important. Pediatricians, gynaecologists and other health care workers should strive to create awareness and make vitamin D supplementation readily available in their communities, especially for those children most at risk. Vitamin D deficiency is high among pregnant mothers. Lack of exposure to sun (parda/veil) is a statistically significant risk factor for vitamin D deficiency. Mothers who themselves are deficient in vitamin D are also producing babies who are deficient in vitamin D. References: 1. Holick MF: High prevalence of vitamin D inadequacy and implications for health. 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