Currently vitamin D deficiency has become the extensive topic of investigation as its role has been identified in various disorders besides its known skeletal side effects. Vitamin D deficiency prevails in extensive proportions all over India with the prevalence of 70 - 100% in the general population, yet it has been neglected, undiagnosed and untreated.1India is located between 8.4 and 37.6 degrees N latitude and Indians obtain most of their vitamin D through adequate sun exposure. But the prevalence of Vitamin D deficiency is high in India. Dark skin color, increased indoor working hours and pollution, limit the sun exposure. Inadequate sun exposure results in decreased vitamin D synthesis and eventually poor vitamin D levels. Dietary vitamin D intake is very low in India because of poor consumption of vitamin D rich foods, lack of fortification and scarce use of supplements. 2 Vitamin D levels were found to be significantly different in the males and females. Confinement to household work, social norms of modesty related to our Indian culture warrant most parts of the body to be covered in females. Also the wish to obtain a fairer skin in females compelling the use of sunscreens and umbrella reduces sun exposure.3

Serum levels of 25-hydroxyvitamin D [25(OH)D] are documented as the best markers of total vitamin D stores in body. Reference values have been suggested for evaluation of vitamin D status. If vitamin D level is ≤20 ng/ml, it is denoted as “deficiency”, if it is in range of 21-29 ng/ml “insufficiency”, and if the level ≥ 30 ng/ml it is “sufficiency”. If 25-OH vitamin D level exceeds 150 ng/ml, it is known as intoxication. 4 Vitamin D deficiency has been linked with various disorders like hypertension, diabetes, obesity eventually leading to augmented risk of cardiovascular mortality.5

 A number of studies have revealed an inverse correlation between vitamin D levels and body mass index (BMI)6,7. Increasing prevalence of obesity and the metabolic syndrome is seen in India. The main causes are industrialization, urbanization, changes in lifestyles of people, nutrition transition, all leading to excessive calorie intake, On the contrary decrease in physical activity results in less energy expenditure.8 The pathophysiology causing decreased vitamin D levels in obese are not completely understood, but possibly being a fat-soluble vitamin, it gets stored in adipose tissue thus decreasing the bioavailability. 9 Also obese individuals have inactive lifestyle leading to reduced amount activity and thus decreased sun exposure.10

 In rising pandemic of obesity, recognizing the prevalence of Vitamin D deficiency in females can be one of the modifiable risk factors in them. This cross-sectional study was undertaken with the objective to estimate Vitamin D status and correlate it with BMI, among apparently healthy females in age group of 30-60 years.

The study participants comprised of 100 apparently healthy looking females, from Chh.Sambhajinagar, Maharashtra in the age group of 30-60 years. This study was cross-sectional and conducted from December 2023 to June 2024. The participants of study were informed and written consent was taken. Females with chronic diseases, pregnant and lactating women, those taking drugs for obesity, Vitamin D or calcium supplementations for last 3 months, were excluded. A proper history was taken and inclusion-exclusion criteria precisely looked over.

Weight was measured with an precision of 0.1 kg using a digital weighing scale. Height was measured using a stadiometer without wearing footwear. Calculation of BMI done by formula, weight (in kg)/height (in m2). Those with BMI ≥25 kg/m2 were considered as obese while < 25 as non-obese.11

Biochemical Parameters: 2 ml Venous blood was collected from all participants in plain bulb. Serum was separated within 2 hours of collection by centrifugation, for analyzing 25(OH) D levels. The serum level of 25(OH) D was measured by fully automated Chemi Luminescent Immuno Assay (CLIA). Vitamin D deficiency was defined as 25(OH)D ≤ 20 ng/ml and level of 21-29 ng/ml was insufficient while ≥ 30ng/ml was considered optimal.

Statistical Analysis: Vitamin D and BMI were assessed among participants as percentage. Mean ± standard deviation were expressed. To find whether there is any significant difference in average levels of the parameters of study between obese and non-obese group, student t-test was used. Pearson correlation coefficient of vitamin D with BMI was calculated. A significant level of 95% was taken for all test.

A total of 100 females were enrolled in the study after reviewing inclusion-exclusion criteria. On basis of vitamin D levels, the individuals were divided into three groups, Vitamin D sufficiency: (25(OH) D ≥30 ng/ml), vitamin D insufficiency: (25(OH) D 21-29 ng/ml), vitamin D deficiency: (25(OH) D ≤20 ng/ml). Amongst the study participants approximately 18% (n=18) were found to be vitamin D sufficient, 70% (n=70) were found to be vitamin D insufficient and 12 % (n=12) were vitamin D deficient. (figure1). Amongst the study participants, 35 were found to be non-obese (BMI<25 kg/m²) and remaining 65 were obese with BMI≥25 kg/m². (figure 2)

Vitamin D status was compared between obese and non-obese group and Chi square test showed a significant difference (p < 0.01). In obese group 9 females were vitamin D deficient, 51 were insufficient and only 5 was found to be sufficient. While in non-obese group 3, 19 and 13 females were deficient, insufficient and sufficient respectively. (Table 1, figure 3).

The participants were in the age group of 30-60 years and the mean age was 41.30 ± 9.01 years. Analysis of the data by Pearson correlation revealed that serum level of 25(OH)D was having significant negative correlation with BMI (r=−0.785), as shown in table 2

 Table 3 shows comparison of various parameters between obese and non-obese groups. There was no significant difference in age between the two groups. BMI and Vitamin D levels showed significant difference between obese and non-obese (P-value<0.001)

Table 1: Chi square test of vitamin D status among obese and non-obese

Table 2: Pearson correlation of serum vitamin D levels with BMI .

Table 3: Comparison of variables between obese and non-obese

In India, Vitamin D deficiency is widespread. However, the clinically diagnosed cases represent only the tip of the iceberg. With the information of the multiple consequences, it can cause; we can envision the problem it would cause. Vitamin D deficiency needs to be addressed with due attention and strong action. Owing to its diverse effects on health, the extensive vitamin D deficiency in India will considerably add to the huge burden on the system of health care.12 In the present study, approximately 18% (n=18) females were found to be vitamin D sufficient, 70% (n=70) were found to be vitamin D insufficient and 12 % (n=12) were vitamin D deficient. The very high prevalence of vitamin D deficiency and insufficiency (82%) is consistent with previous studies. A study conducted by Agarwal et al. showed that only 5.6% subjects had normal 25-OHD level and 7.0% had vitamin D insufficiency while 87.3% were vitamin D deficient, with mean serum 25-OHD levels being 12.73 ± 7.63 ng/ml; 81% were obese and 25-OHD levels inversely correlated with BMI .13 Bhatt et al. demonstrated that the prevalence (%) of vitamin D deficiency, insufficiency and sufficiency was 68.6, 25.9 and 5.5, respectively and obesity was 61.7% in their study.14 Goswami et al. showed that in spite of plentiful sunlight, healthy people of Delhi were vitamin D deficient. Apart from inadequate direct sunlight, low-calcium, high-phytate diets, skin pigmentation of Indians, pregnancy in females, and climatic variations may affect vitamin D levels.15

 In our study population about 35% females were non obese and 65%were obese. We found significant difference in vitamin D levels among obese and non obese groups. Obesity is associated with alterations in the vitamin D physiology as seen from our and some previous studies demonstrating a negative correlation of vitamin D levels with BMI. Vitamin D being fat soluble gets accumulated in the adipose tissue and its bio availability is reduced for action. Vitamin D regulates various processes and its dysregulation leads to metabolic disorders. The molecular response to vitamin D in fat tissue affects energy metabolism and adipokine and cytokine production by the regulation of genes participating in antioxidant defense mechanism, adipocytes differentiation, and apoptosis. Thus, its deficiency disturbs lipid storage, thermogenesis, causes inflammation, and oxidative stress. Reestablishing the proper function in obese individuals is of utmost importance in to decrease the risk of obesity-related complications, such as diabetes and cardiovascular diseases. Vitamin D supplementation may aid in correcting adipose tissue dysfunction and treatment of obesity.16

Vitamin D insufficiency is widespread among Indian females and it is significantly associated with obesity. Affordable vitamin D supplements and vitamin D fortified foods. educational programs to create awareness, affordable facilities for testing Vitamin D levels are some of measures to combat the Vitamin D deficiency. Vitamin D levels should be assessed in females with higher BMI. This may be helpful in treatment of obesity and prevention of further complications

1. Garg R, Agrawal P, Malhotra N. Prevalence of vitamin D deficiency in Indian women. Int J Reprod Contracept Obstet Gynecol. 2018 ;Jun;7(6):2222-2225
2. Babu US, Calvo MS. Modern India and the Vitamin D dilemma: Evidence for the need of a national food fortification program. Mol Nutr Food Res. 2010;54:1134–47.
3. Shukla K, Sharma S, Gupta A, Raizada A, Vinayak K. Current Scenario of Prevalence of Vitamin D Deficiency in Ostensibly Healthy Indian Population: A Hospital Based Retrospective Study. Indian J Clin Biochem. 2016 Oct;31(4):452-7. doi: 10.1007/s12291-016-0552-2. Epub 2016 Feb 1. PMID: 27605743; PMCID: PMC4992490.
4. Holick MF, Binkley NC, Bischoff-Ferrari HA, Gordon CM, Hanley DA, Heaney RP, et al. Evaluation, treatment, and prevention of Vitamin D deficiency: An endocrine society clinical practice guideline. J Clin Endocrinol Metab. 2011;96:1911–30.
5. Martins D, Wolf M, Pan D, Zadshir A, Tareen N, Thadhani R, et al. Prevalence of cardiovascular risk factors and the serum levels of 25-hydroxyvitamin D in the United States: Data from the Third National Health and Nutrition Examination Survey. Arch Intern Med. 2007;167:1159–65.
6. Parikh SJ, Edelman M, Uwaifo GI, et al. The relationship between obesity and serum 1,25-dihydroxy vitamin D concentrations in healthy adults. J Clin Endocrinol Metab 2004;89:1196-9
7. Vimaleswaran KS, Berry DJ, Lu C, Tikkanen E, Pilz S, Hiraki LT, et al. Causal relationship between obesity and Vitamin D status: Bi-directional mendelian randomization analysis of multiple cohorts. PLoS Med. 2013;10:e1001383.
8. Misra A, Khurana L. Obesity and the metabolic syndrome in developing countries. J Clin Endocrinol Metab 2008; 93(11 Suppl 1):S9–S30
9. Wortsman J., Matsuoka L.Y., Chen T.C., Lu Z., Holick M.F. Decreased bioavailability of vitamin D in obesity. Am. J. Clin. Nutr. 2000;72:690–693.
10. Holick MF. Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease. Am J Clin Nutr 2004;80(6 Suppl):1678S-88S.
11. Misra A, Chowbey P, Makkar BM, Vikram NK, Wasir JS, Chadha D, Joshi Sr, Sadikot S, Gupta R, Gulati S, Munjal YP: Consensus Group: Consensus statement for diagnosis of obesity, abdominal obesity and the metabolic syndrome for Asian Indians and recommendations for physical activity, medical and surgical management. J Assoc Physicians India 2009;57:163–170.
12. Aparna P, Muthathal S, Nongkynrih B, Gupta SK. Vitamin D deficiency in India. J Family Med Prim Care. 2018 Mar-Apr;7(2):324-330.
13. Agarwal N, Mithal A, Kaur P, Dhingra V, Godbole MM, Shukla M. Vitamin D and insulin resistance in postmenopausal Indian women. Indian J Endocrinol Metab. 2014;18(1):89-93.
14. Bhatt S, Misra A, Gulati S, Singh N, Pandey R. Lower vitamin D levels are associated with higher blood glucose levels in Asian Indian women with pre-diabetes: a population-based cross-sectional study in North India MJ Open Diab Res Care 2018;6:e000501. doi:10.1136/bmjdrc-2017-000501
15. Goswami R, Gupta N, Goswami D, Marwaha RK, Tandon N, Kochupillai N, et al. Prevalence and significance of low 25-hydroxyvitamin D concentrations in healthy subjects in Delhi. Am J Clin Nutr 2000; 72 : 472-5.
16. Szymczak-Pajor I, Miazek K, Selmi A, Balcerczyk A, Śliwińska A. The Action of Vitamin D in Adipose Tissue: Is There the Link between Vitamin D Deficiency and Adipose Tissue-Related Metabolic Disorders? Int J Mol Sci. 2022 Jan 16;23(2):956. doi: 10.3390/ijms23020956. PMID: 35055140; PMCID: PMC8779075.