|Year : 2015 | Volume
| Issue : 1 | Page : 12-15
Does Diet Offset the Effect of Veiling on Bone Mineral Density of premenopausal Indian women
Seema Kapoor, Sangeeta Gupta, Marwaha, Mani Kalavani, Madhulika Kabra, Sanjeev Pandey, Sunil Kumar Polipalli
Division of Genetics, Department of Pediatrics, MAMC & associated Lok Nayak Hospital, New Delhi, India
|Date of Web Publication||27-Jan-2015|
Dr. Seema Kapoor
Division of Genetics, Department of Pediatrics, MAMC Associated Lok Nayak Hospital, New Delhi
Source of Support: None, Conflict of Interest: None
Objective: To determine the effect of veiling on bone mineral density (BMD) and to evaluate its association with Vitamin D, Vitamin B12, and folate status. Materials and Methods: Design: Cross-sectional observational study. Subjects : Two hundred and forty-seven women in the perimenopausal stage in the age range between 40 and 50 years were evaluated by dual energy X-ray absorptiometry for BMD status of the spine, femur, and forearm. Serum calcium, phosphorus, alkaline phosphatase, 25 (OH) D, Vitamin D, Vitamin B12 and folate were estimated. This study group was segregated into veiled and unveiled depending upon the coverage during day time with a dark cloth. Sunlight exposure and levels of physical activity were assessed by a questionnaire. Biochemical variables and BMD at various sites across the skeleton were compared. Results: The veiled group had significant hypovitaminosis D as compared to the unveiled. The Vitamin D in the veiled group was 11.3 ± 17.2 ng/ml versus 19.9 ± 27.6 ng/ml (P < 0.001) in the unveiled. Women in the veiled group had less sunlight exposure and were less physically active (P < 0.001 and 0.05 respectively). The basic biochemical parameters were comparable in both groups. Vitamin B12 was higher in the veiled group, and folate levels were higher in the unveiled group the difference being statistically significant. Homocysteine levels were minimally higher in the veiled group. The BMD across the different skeletal sites did not differ, though the unveiled group had a slightly higher BMD at all sites apart from the trochanter. Conclusions: BMD is affected by multiple factors, and its complex interaction may explain the normal biochemical parameters of bone metabolism even in the presence of hypovitaminosis D in the veiled group.
Keywords: Veiling, BMD, Premenopausal
|How to cite this article:|
Kapoor S, Gupta S, Marwaha, Kalavani M, Kabra M, Pandey S, Polipalli SK. Does Diet Offset the Effect of Veiling on Bone Mineral Density of premenopausal Indian women. MAMC J Med Sci 2015;1:12-5
|How to cite this URL:|
Kapoor S, Gupta S, Marwaha, Kalavani M, Kabra M, Pandey S, Polipalli SK. Does Diet Offset the Effect of Veiling on Bone Mineral Density of premenopausal Indian women. MAMC J Med Sci [serial online] 2015 [cited 2019 Aug 18];1:12-5. Available from: http://www.mamcjms.in/text.asp?2015/1/1/12/150052
| Introduction|| |
Osteoporosis is now recognized as an emerging epidemic and is threatening to reach significant proportions. Dietary habits, body mass index (BMI) distribution, gestational history, levels of physical activity, duration of direct sunlight exposure and genetic milieu are few of the factors influencing bone mineral density (BMD). Vitamin D also known as the "sunshine vitamin" is one of the primary regulators of calcium status and bone mineralization of the body.  This is attributed to its critical role in the absorption of calcium and phosphorus in intestine and in the differentiation of cells of the osteoblastic lineage.  Although a small amount of Vitamin D is supplied from food, skin exposure to ultraviolet (UV) rays in sunlight is a major source. A religious code of conduct that ensures that all women wear a veil or concealing clothing is, therefore, likely to interfere with cutaneous Vitamin D synthesis.
Data suggest that serum folate also has a strong relationship with BMD. Several hypotheses have been put forward to explain this relationship. Low serum folate maybe an index of an unbalanced diet leading to deficiency of nutrients necessary for bone mineralization. A direct effect of folate on bone cells as folate is necessary for various intracellular processes like preventing DNA damage, apoptosis and reducing oxidative stress.  Some of these mechanisms seem to be mediated by increased homocysteine levels. 
Vitamin B12 has been shown to influence BMD through alterations in homocysteine. Decreased level of B12 is associated with decreased level of markers of bone formation such as serum alkaline phosphatase (ALP) and osteocalcin.  An association between serum Vitamin B12 concentration, (3H) thymidine incorporation into human bone marrow stromal osteoprogenitor cells and UMR-106 osteoblastic cells, suggest a direct effect of Vitamin B12 on osteoblast cell series. 
Body mass index and physical activity are additional important determinants of bone health. Apart from having less cutaneous synthesis of Vitamin D due to less outdoor exposure, veiled Indian women lead a sedentary life, and therefore by presumption would have a lower BMD than their unveiled counterparts. The study, therefore, aimed to investigate the differences in BMD in veiled and unveiled Indian women in premenopausal age group.
| Materials and Methods|| |
The study had approval of the Institute's Human Ethics Committee, and the subjects gave voluntary consent after the aims and objectives were explained to them. The subjects for the study were 247 sequentially presenting and unrelated premenopausal Indian women in the fifth decade. This study group was segregated into veiled when they primarily wore a loose black outer garment over the normal dress covering the whole body with the exception of eyes. All members belonged to Islamic religion. The other women enrolled in the study wore traditional Indian or Western dresses without an outer black garment with the face and arms frequently exposed, were classified as unveiled.
Detailed information on age, medical history, family history, and lifestyle was obtained from all subjects. Exclusion criteria included endocrinological disorders (Hyperthyroidism, hypo/hyper parathyroidism, diabetes mellitus), chronic disorders of liver and kidney and other skeletal disorders (Paget's disease, osteogenesis imperfecta, and rheumatoid arthritis). Use of medications known to affect bone density and metabolism (such as vitamins, corticosteroids, anticonvulsants, heparin) were criteria for exclusion. All these women were engaged in usual physical activities and household chores. None of the enrolled women smoked or consumed alcohol.
Sunlight exposure was assessed by a questionnaire illustrating duration of direct sunlight exposures, areas exposed and frequency of such exposures per week. Physical activity was estimated by a questionnaire about nature of household duties, walking or participation in active aerobics
Fasting blood samples were withdrawn for calcium, phosphorus, ALP, Vitamin B12, folate, homocysteine, basic kidney, and liver profile. Homocysteine was measured by high-performance liquid chromatography system on an ample, which had been separated from the cells within 1 h of puncture and stored at − 20°C. The inter-assay coefficient of variation was 2.6% at 15.5 μmol/L and 6.8% at 17.8 μmol/L. Vitamin B12 and folate were estimated by electrochemiluminescence using commercially available kits by Roche diagnostics. The intra-assay coefficient was 6.4% at a concentration of 4.9 ng/ml for folate and 7.3% for a concentration of 276 pmol/L for Vitamin B12. Calcium, phosphorus, ionic calcium and ALP were assayed the same day on an autoanalyzer.
All the subjects had undergone BMD measurements by dual energy X-ray absorptiometry (DEXA) (Lunar Prodigy, USA) at the forearm, various levels of spine and hip inclusive of ward's triangle, the greater trochanter, and neck of femur. The DEXA machine was calibrated daily with the same phantom. The co-efficient of variation in BMD was < 1% to < 2% depending upon bone site categorization that was done according to World Health Organization (WHO) proposed algorithm of T score, with a T score between − 1 and − 2.5 representing osteopenia whilst a T score of < −2.5 reflected osteoporosis. Bone density was calculated in g/cm 2 .
Results were obtained as mean ± standard deviation. The comparison of continuous variables was performed using the Kruswal-Wallis and Mann-Whiteney U test if the distribution was skewed. In the remaining normally distributed variables analysis of variance was used for comparison. Differences were considered significant at P < 0.05. The BMD at various sites was adjusted by analysis of covariance for age, height, and weight.
| Results|| |
The subjects were those who presented sequentially to the Gynecology Outpatient Department . All subjects were nonsmokers. Five daily wage laborers with a significantly high level of physical activity belonging to the veiled group were excluded from the analysis. The demographic and biochemical data of both the groups are given in [Table 1]. The two groups were comparable when age alone was considered. The veiled group was heavier with higher BMI that may have been due to a sedentary lifestyle. On dietary analysis, all veiled women were nonvegetarians, and 68% of unveiled subjects were primarily vegetarians with 22% of them consuming eggs occasionally while 10% consumed nonvegetarian food occasionally.
|Table 1: Veiled versus unveiled: Comparison of demographic and biochemical parameters |
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Compared with unveiled group, women in a veiled group had less sunlight exposure and were less physically active (P < 0.001 and 0.05 respectively). Ninety-one percent had started using the veil after puberty and 18% much before menarche. Their exposure to sunlight was only while hanging clothes at roof top or in the backyard. Six percent of them confessed that when they would accompany their husbands to a remote place they discarded the veil thus accounting for some sun exposure. The average exposure to erythemal dose of sunlight was < 10 min/week in the veiled group and ranging from 15 to 48 min in the unveiled group. Veiled group demonstrated significant hypovitaminosis D and the difference between the two groups was statistically significant.
The basic biochemical parameters that are, serum calcium, phosphate and ionic calcium were comparable in both groups. ALP was higher in the veiled group, and the difference was statistically significant. [Table 1] depicts demographic and biochemical parameters in both the groups. Vitamin B12 was higher in the veiled group, and folate levels were higher in the unveiled group with the difference being statistically significant. Homocysteine levels were minimally higher in the veiled group. The BMD across the different skeletal sites did not differ. [Table 2] depicts the BMD at various skeletal sites in the veiled and unveiled groups. Although mean BMD at all sites in the veiled group was less than that in the unveiled group, the results were statistically insignificant. [Table 3] depicts the proportion of women in both the groups who were normal, osteopenic and osteoporotic using the WHO criteria.
|Table 3: Proportion of women with normal BMD, osteopenia and osteoporosis in between the veiled and unveiled group|
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| Discussion|| |
The prevalence of hypovitaminosis D in sunny countries is compounded by religious compulsion of wearing concealing clothing. This study envisaged to address this issue was conducted in Delhi. The average duration of cloud-free sunshine during the years of this study was 3.6 h/d in the winter and 7.0 h/d in summer in Delhi (28.35°N and 77.12°E with zenith angle of 84.5° in peak summer and 38.5° in peak winter [Meteorology Department, Delhi]). The ground surface of Delhi receives four minimal erythemal dose (MED) of UV radiation/d during the summer and only one MED/d in the winter. When the body is exposed to one MED (i.e. slight redness of the skin) sunlight, there is an effect equal to 10,000-25,000 IU oral Vitamin D intake.  Exposure of hands, face arms and legs two to three times a week is generally enough for sufficient Vitamin D production. Veiled women are highly unlikely to receive the MED, and this explains the hypovitaminosis in that group. The Vitamin D in the veiled group was 11.3 ± 17.2 ng/ml and in the unveiled group was 19.9 ± 27.6 ng/ml (P < 0.001). Ninety to one hundred percent of Vitamin D needed is formed in the skin after adequate sunlight exposure and rest is met by diet. Factors affecting production of Vitamin D include season, latitude, altitude, hour of the day, skin pigmentation and clothing style.  However with optimal exposure in unveiled groups. Vitamin D levels were still low. Similar observations have been made by Goswami et al., when they studied volunteers, soldiers, physicians and nurses, pregnant women, newborns and depigmented people in Delhi.  They also commented that the relative normalization of serum calcium could have been attained through a parathyroid hormone mediated resorptive process of the bone mineral. Similar observations were made in this study group when both the subgroups had normal total calcium and ionic calcium levels. Despite this low value, there was no effect on BMD at any skeletal site suggesting that other factors had offset its effect or the yet unknown factors operated in this neutrigenomic milieu.
Similar Vitamin D deficiency has been reported by Hatun et al. in adolescent girls from Turkey and in Muslim and orthodox Jewish communities from the far East.  Güler et al. have also highlighted the relative Vitamin D deficiency in sunny countries where fortification of food with Vitamin D is not routine.  El-Sonbaty et al. in a similar study from Kuwait compared women aged 14-45 years according to an outfit and found significantly lower Vitamin D levels in the covered group but with normal calcium and phosphorus.  This strengthens the association of style of dressing influencing the Vitamin D status. Clothing from head to toe presents a major problem to Vitamin D status. Poor correlation of BMD with low Vitamin D status is a well-documented fact. Similar observations had been made by Guzel et al. when they evaluated Vitamin D status of veiled and unveiled Turkish women.  Vitamin D deficiency has been reported in up to 80% of pregnant women as well as reproductive women in Turkey. Mishal also evaluated the effect of concealing clothing on BMD and had similar observations. 
Most of these women from the Islamic sect had high Vitamin B12 levels presumably because of the nonvegetarian diet. Vitamin B12 deficiency has been linked to low ALP levels as a marker for cell turnover, in our study group they had high levels of ALP, which we are unable to explain. The vegetarians on the other hand had better folate levels; suggesting complex interactive processes affecting bone health. It is also suggested that higher BMI in the veiled group may have been an additional factor in normalization of BMD as BMI is known to significantly influence BMD. This can be explained by the peripheral estrogen production taking place in the adipose tissue, which may confer a positive impact on the BMD.
Cultural practices are even more pronounced in India. On one hand are the religious compulsions that significantly alter lifestyle, body health and bone health in particular and on the other hand, there is lack of food fortification with Vitamin D. The sect to which they belong practices a larger family norm, which pronounce dietary inadequacies. It is therefore suggested that Vitamin D supplementation should be universal not only to improve bone health but for its known positive role in protection against cancers of the colon, ovaries, prostate, breast and type 1 diabetes. It is already known that on exposure of 6% body weight to MED for 5 min at least 2-3 times/week leads to synthesis of 25 μg of Vitamin D. It is also suggested that these women should be advised to be exposed to at least one MED of sunlight 2-3 times/week while following the cultural practices as required by the sect in public to meet the requirements of this sunshine vitamin, which may confer benefits much beyond only improving their bone health.
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[Table 1], [Table 2], [Table 3]