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ORIGINAL ARTICLE
Year : 2020  |  Volume : 13  |  Issue : 4  |  Page : 315-320  

Prevalence of metabolic syndrome, vitamin D level, and their association among elderly women in a rural community of West Bengal, India


1 Department of Microbiology, Lady Brabourne College, University of Calcutta, Kolkata, West Bengal, India
2 Department of Biochemistry and Nutrition, All India Institute of Hygiene and Public Health, Kolkata, West Bengal, India
3 Department of Community Medicine, IQ City Medical College and Narayana Hrudayalaya Hospital, Durgapur, West Bengal, India

Date of Submission09-Aug-2019
Date of Decision28-Oct-2019
Date of Acceptance31-Dec-2019
Date of Web Publication20-Jul-2020

Correspondence Address:
Joyeta Ghosh
Department of Microbiology, Lady Brabourne College, University of Calcutta, Kolkata - 700 017, West Bengal
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/mjdrdypu.mjdrdypu_229_19

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  Abstract 


Objective: The present study aimed to find out the prevalence of metabolic syndrome (MS) and 25-hydroxyvitamin D (25[OH] D) status as well as their association among rural elderly women of West Bengal, India. Materials and Methods: This cross-sectional study was conducted among elderly women residing at Amdanga Block, North 24 Parganas District of West Bengal, India, from April 2014 to August 2018. A total of 236 randomly selected rural elderly women aged between 60 and 70 years of age were included. Serum 25(OH)D, blood pressure (BP), waist circumference (WC), fasting blood glucose (FBG), triglycerides (TGs), and high-density lipoprotein cholesterol (HDL-C) were measured using standard procedures. MS was defined as per the International Diabetes Federation, 2005 (for Asian-Indians) criteria. Statistical tests were done using SPSS software. Results: The prevalence of Vitamin D deficiency (VDD)/Vitamin D insufficiency was 53.5%. The prevalence of MS was 34%. Of all the studied elderly having MS, 23.2% and 34% were Vitamin D insufficient and deficient, respectively. Among the studied women, 18.3% and 45% with WC ≤80 cm; 21.4% and 42.9% with FBG >100 mg/dl; 22.8% and 33.7% with TG ≥150 mg/dl; 22.1% and 31.1% with HDL-C <50 mg/dl; and 22% and 34.2% with BP ≥130/85 mm of Hg had Vitamin D insufficiency and VDD, respectively. Significant statistical association was found between WC (P = 0.003) and MS (P = 0.008) with serum 25(OH)D status using Chi-square test (P = 0.01). Significant negative correlation existed between WC, MS, and serum 25(OH)D level. MS itself found to predict the serum 25(OH)D level significantly. Conclusion: 25(OH)D had significant inverse and direct relationship with MS and WC. Low 25(OH)D may be one of the potential risk factors for developing MS in elderly women or vice versa.

Keywords: India, metabolic syndrome, rural elderly women, Vitamin D, waist circumference


How to cite this article:
Ghosh J, Chaudhuri D, Saha I, Chaudhuri AN. Prevalence of metabolic syndrome, vitamin D level, and their association among elderly women in a rural community of West Bengal, India. Med J DY Patil Vidyapeeth 2020;13:315-20

How to cite this URL:
Ghosh J, Chaudhuri D, Saha I, Chaudhuri AN. Prevalence of metabolic syndrome, vitamin D level, and their association among elderly women in a rural community of West Bengal, India. Med J DY Patil Vidyapeeth [serial online] 2020 [cited 2020 Sep 27];13:315-20. Available from: http://www.mjdrdypv.org/text.asp?2020/13/4/315/290169




  Introduction Top


India is experiencing a dramatic demographic transition, entailing almost a tripling of the population over the age of 60 years. At present, India is the second-largest populous country in Asia as well as in World.[1] Elderly are at high risk of Vitamin D deficiency (VDD) worldwide.[2] VDD has been found to be prevalent among Indian elderly women residing in different parts of the country.[3],[4],[5],[6],[7],[8],[9],[10],[11],[12],[13]

Increasing age increases the risk of metabolic syndrome (MS), and for elderly women with menopause and hormonal changes, it may increase the risk of cardiovascular diseases (CVDs) among them.[14] Previous studies reported that VDD is one of the important determinants of MS.[3],[15] There are reports available on the association of MS and serum 25-hydroxyvitamin D (25[OH] D) level among the rural elderly women in India.[4],[11],[12],[13] The present study aimed to find out the prevalence of MS and serum 25(OH)D status as well as to find out their association among rural elderly women of West Bengal, India.


  Materials and Methods Top


This cross-sectional study was conducted among 236 elderly women, aged 60–70 years, selected randomly from 80 villages of Amdanga block, 24th Parganas North, West Bengal, India, from April 2014 to August 2018. Multistage probability sampling is used to select noninstitutionalized (≥60 years of age) female elderly population. At the first stage, 30 villages were selected randomly from Amdanga block area, North 24 Parganas, West Bengal. In the second stage, by following systematic random sampling method, 236 elderly women were selected from that previously selected 30 villages separately and were screened according to the objectives of this study.

Ethical clearance was obtained from the Ethics Committee of All India Institute of Hygiene and Public Health, Kolkata. Informed written consent was obtained before the study. Elderly women having a history of thyroid dysfunction, on hormonal replacement therapy, with amenorrhea due to any pathological cause or surgery, on Vitamin D supplementation, with physically or mentally challenged, and with noncooperative in nature were excluded from the study.

Blood sampling of the subjects was performed by a trained phlebotomist by venipuncture after 10–12 h overnight fast. Samples were transported to the laboratory in an ice bucket within 2 h of collection, and serum was separated by centrifugation of whole blood for 20 min at 2000 rpm. Serum 25(OH)D3 was measured by enzymatic immunoassay.[16] Precision of the estimation was determined by intra-assay and inter-assay variability. Deficiency, insufficiency, and sufficiency of Vitamin D were defined as <20, 21–29, and 30–100 ng/ml of serum 25(OH)D in the human blood, respectively. Fasting blood glucose (FBG), blood pressure (BP), waist circumference (WC), serum triglycerides (TGs), and high-density lipoprotein cholesterol (HDL-C) were measured using standard procedures.[17],[18],[19],[20],[21],[22],[23],[24],[25],[26],[27] Fasting blood measures including serum glucose were measured using glucose oxidase–peroxidase method,[23] and BP was measured on the right arm of the participants in a relaxed, sitting position with the arm supported at heart level, using a standard mercury sphygmomanometer.[17] WC measurements were done using standard protocol[24] (nearest 0.2 cm); participants were requested to wear light clothes and not to wear shoes/socks for the measurements. Serum TGs were measured by glycerol oxidase–peroxidase amino antipyrine method[25] using assay kits from Span Diagnostics Limited in a semi-autoanalyzer. HDL-C was determined by cholesterol oxidase–peroxidase amino antipyrine method after precipitation of low-density lipoprotein cholesterol (LDL-C) and very LDL-C.[26] MS was defined as per the International Diabetes Federation, 2005 (for Asian-Indians) criteria.[21]

Statistical analysis

Data were put in Microsoft Excel worksheet (Microsoft, Redwoods, WA, USA) and checked for accuracy. Association between two attributes was calculated by Pearson's Chi-square test. Continuous data were first checked for normality distribution by Kolmogorov–Smirnov test. Significant P value indicated skewed distribution. Thus, continuous data were presented in median and interquartile range. Because of skewed distribution, nonparametric tests were performed. Difference between distributions of two continuous variables was determined by Mann–Whitney U-test (Z value). Correlation was calculated by Spearman's correlation coefficient (rho). Binary multivariable logistic regression was calculated using Statistical Package for the Social Sciences software, version 20.0 (SPSS Inc., Chicago, IL, USA), by keeping nonsufficient Vitamin D level (yes/no) as dependent variable. P ≤ 0.05 was considered statistically significant.


  Results Top


Mean age of the targeted elderly women was 62 ± 4 years. The mean serum Vitamin D level was 29.73 ± 17.29 ng/ml. [Table 1] shows that 34% of women were deficient, 19.5% of women were insufficient, and 46.5% of women were normal. Overall, 53.5% of elderly women were suffering from VDD or insufficiency. MS was found among 34% of the rural elderly women studied. Of all the studied elderly having MS, 23.2% and 34% were Vitamin D insufficient and deficient, respectively. Among the studied women, 18.3% and 45% with WC ≤80 cm; 21.4% and 42.9% with FBG >100 mg/dl; 22.8% and 33.7% with TG ≥150 mg/dl; 22.1% and 31.1% with HDL-C <50 mg/dl; and 22% and 34.2% with BP ≥130/85 mm of Hg had Vitamin D insufficiency and VDD, respectively. Significant statistical association was found between WC (P = 0.003) and MS (P = 0.008) itself with serum 25(OH)D status using Chi-square test (P = 0.01) [Table 1].
Table 1: Distribution of elderly women according to serum 25-hydroxyvitamin D level in relation to metabolic syndrome, waist circumference, fasting blood glucose, triglyceride, high-density lipoprotein cholesterol, and blood pressure (n=236)

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Median serum 25(OH)D was found to be 28.18 ng/ml. Median serum 25(OH)D level varied from 23.8 to 32.7 ng/ml among the elderly having or not having MS. Subjects having MS had significantly (P = 0.002) lower serum 25(OH)D level compared to subjects without MS, as revealed by Mann–Whitney U-test. A significant (P = 0.002) negative correlation was found between serum 25(OH)D and MS status. Median serum 25(OH)D level had increased significantly (P = 0.005) in Mann–Whitney U-test from 23 to 32.5 ng/ml in subjects having WC <80 cm to ≤80. Between WC and serum 25(OH)D, a significant inverse relationship was observed (P = 0.005). There is no significant relationship observed between FBG and serum 25(OH)D level. In systolic blood pressure (SBP), the median serum 25(OH)D varied from 27.4 to 31.2 ng/ml, and in diastolic blood pressure (DBP), it was 24.5–32.1 ng/ml among the rural elderly women having or not having hypertension. This change in serum 25(OH)D in case of DBP was significant according to Mann–Whitney U-test; further, a significant inverse relationship was observed in case of DBP among rural elderly women. Median 25(OH)D level decreased (28–27 ng/ml) with increase in TG level (<150–≤150 mg/dl), while median serum 25(OH)D level increased (27–28 ng/ml) with increase in HDL cholesterol level (<50–≤50 mg/dl); and there had been insignificant difference between these groups in Mann–Whitney U-test and no relationship was observed between either of them (P = 0.44 and P = 0.96, respectively) in Spearman's correlations [Table 2].
Table 2: Relationship of waist circumference, fasting blood glucose, triglycerides, high-density lipoprotein-cholesterol, and blood pressure with serum 25-hydroxyvitamin D among rural elderly women (n=236)

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The binary logistic regression model fitted well as evident from significant Omnibus Chi-square statistic (P = 0.042) and nonsignificant Hosmer–Lemeshow statistics (0.558). Independent variables could explain between 5.4% and 7.2% variation of dependent variable (serum 25[OH] D) as found from Cox and Snell R2 and Nagelkerke R2, respectively. The model correctly classified 60.2% of cases overall from classification table. None of the parameters of MS tested (FBG, TG, HDL-C, WC, BP, and MS) alone could predict the serum 25(OH)D level significantly; however, among all the independent variables, MS found to predict the serum 25(OH)D level significantly [Table 3].
Table 3: Binary logistic multivariable model analysis of serum 25-hydroxyvitamin D with fasting blood glucose, triglyceride, high-density lipoprotein cholesterol, waist circumference, blood pressure, and metabolic syndrome

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  Discussion Top


VDD was thought to be rare in India due to their exposure to sunshine, which is supported by the results of earlier epidemiological studies regarding the frequencies of rickets and osteomalacia in the Indian subcontinent.[28] Earlier studies reported that 54.2% of urban elderly women at Hyderabad, 84.9% of 30–65 years elderly from Odisha, 58% of elderly women from Varanasi, 53.4% of Post menopausal women (PMW) from Jammu and Kashmir, and 84% of South Indian elderly had VDD, respectively.[3],[10],[12],[13] The present research revealed a better Vitamin D status among the elderly women population studied, but still it includes more than half of the studied population, which is not good especially in rural India where ample sun exposure is available. In particular, a recent study on the Vitamin D status of PMW in rural West Bengal reported that the Vitamin D insufficiency and VDD prevalence of 19% and 51%, respectively,[18] was much higher than Vitamin D insufficiency (19.5%) and VDD (34%) prevalence observed in the present study.

Our study revealed that 34.7% of the elderly women were suffering from MS. The prevalence of MS among elderly varies in different parts of India; 28% in Kerala,[29] 28.6% in Uttarakhand,[30] 46% in rural West Bengal,[18] etc. Considering deficiency of Vitamin D as one of the factors for developing MS,[31],[32],[33],[34] it is interesting to observe the association between MS as well as its components and serum 25(OH)D level. It has been observed that there is a significant difference in median serum 25(OH)D level between the groups (normal and abnormal) of each parameter of MS including MS itself. Significant association has been observed between serum 25(OH)D and DBP, WC, and MS. However, no significant association was observed in case of FBG, TG, and HDL. MS, WC, and DBP were inversely correlated with serum 25 (OH) D level, and this relation was found to be statistically significant. There is inverse relationship observed between all other parameters of MS (BP, TG, and HDL) and serum 25(OH)D, but these were not statistically significant. It has been well recognized by many research works that 25(OH)D has protective roles against different components of MS.[18],[32],[33],[34],[35],[36] Previous reports have shown that low circulating 25(OH)D concentration may be associated with an increased prevalence of hyperglycemia, MS, WC, and serum TG.[18],[31],[32],[33],[34],[35] Once an individual develops MS, the combination of risk factors leads to an increased risk of CVD.[36] In the present study, about 45% of the subjects having high WC were deficient in serum 25(OH)D level while 36.7% had sufficient serum 25(OH)D level. In comparison, 24.4% and 55.1% of the subjects having normal WC had deficient and sufficient serum 25(OH)D level. This association was found to be statistically significant according to Pearson's Chi-square test (P = 0.003). Furthermore, median serum 25(OH)D level was found to be significantly higher among subjects having normal WC compared to subjects having high WC (32.5 vs. 23.0 ng/ml). Again, it was observed that, as WC increased, serum 25(OH)D level decreased significantly (P = 0.005). These findings are consistent with previous reports.[21],[32],[33],[34],[35],[36]

Another interesting observation was that the median serum 25(OH)D level was found to be significantly higher among subjects having normal DBP compared to high DBP (32 vs. 24.5 ng/ml). However, no significant association was observed between FBS, TG, HDL, SBP, and serum 25(OH)D level.


  Conclusion Top


Relatively high prevalence of MS as well as Vitamin D insufficiency and VDD existed among rural elderly women of Amdanga block, West Bengal, India. 25(OH)D had significant inverse and direct relationship with MS and WC. According to binary logistic regression model, MS found to predict the serum 25(OH)D level significantly. All the mentioned factors (FBS, TG, WC, HDL, and BP) were inversely correlated with serum 25(OH)D level, which again indicates that low circulating serum 25(OH)D will increase the chances of having abnormal FBS, TG, HDL, or BP. Similar interpretations were observed in many previous reports.[16],[33],[34] Thus, the present study and also previous studies can be said that MS and its different components (as important CVD risk factors) may play a crucial role in low circulating serum 25(OH)D.

Financial support and sponsorship

The financial and other related support has been obtained from the DST-INSPIRE Program Division, New Delhi; Department of Microbiology, Lady Brabourne College, Kolkata, India; and Department of Biochemistry and Nutrition, All India Institute of Hygiene and Public Health, Kolkata.

Conflicts of interest

There are no conflicts of interest.



 
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