ABSTRACT
Introduction:
Cardiovascular diseases remain one of the leading causes of mortality globally with 80% occurring in developing countries. The known modifiable cardiovascular risk factors are Hypertension, Diabetes, Obesity, Hyperlipidaemia, Smoking, and Sedentary lifestyles. The prevalence of these risk factors is highest in Kerala (hypertension 30% and diabetes 14.8%). Globally India has the highest prevalence of cardiovascular disease especially in Kerala. The prevalence of vitamin D deficiency nationally is about 70–100% in some studies but shows contradictory results in various populations in Kerala (children 11% and 89% in perimenopause women). No Known study was done among apparently healthy adults in Kerala. Hence understanding its prevalence and its association if any to the cardiovascular risk factors may help to decrease the prevalence of cardiovascular disease.
Methods:
Subjects were taken from those who attended the health check-up at a tertiary hospital. Blood parameters like FBS, Triglyceride, High-Density Lipoprotein (HDL), and Serum Vitamin D were analyzed along with Blood pressure and waist circumference.
Statistical Analysis:
Frequency and Chi-squared test was done to look for prevalence and association of the various cardiovascular risk factors and vitamin D prevalence using IBM SPSS version 20.0 software.
Result:
It was found that Hypertension was highly prevalent (75%) among the cardiovascular risk factors. The prevalence of deficient and insufficient Vitamin D was 86.9% and it was significantly associated with Hypertension (p = <.001), Diabetes (p = <.001), High Triglycerides (p = <.001), and Low (at risk) High-density Lipoprotein (p = <.001) but not to obesity (P = 1.00).
Conclusion:
High prevalence of deficient and insufficient Vitamin D levels. And this was associated with all the risk factors except obesity. Additional information on low-density lipoprotein, Total Cholesterol, and HbA1c values would be strengthened. Further studies with supplementation preferably done in the community would help to confirm this association.
Keywords: Diabetes, high-density lipoprotein, hypertension, modifiable cardiovascular risk factors, obesity, triglycerides, vitamin D
Introduction
Vitamin D deficiency (VDD) is widespread globally and has become of great public health concern. The US, Canada, and Europe have shown a prevalence of vitamin D deficiency (<20 ng/ml) of 24%[1] 36.8%,[2] and 40%,[3] respectively.[4] A systemic review done in India showed a 70-100% prevalence.[5] Another study in rural Tamil Nadu showed that 55% were deficient.[6]
The prevalence of low Vitamin D in Kerala showed contradictory values. The children showed a low incidence (11%)[7] whereas another study among women in Kerala showed 80-90% had low vitamin D levels (</=30 ng/ml).[8] And in perimenopause women it was 89%.[9] No known study was done among a mixed adult population in Kerala.
Cardiovascular diseases (CVDs) remain one of the leading causes of mortality globally of which 80% occur in middle- and low-income countries.[10] India had the highest prevalence of 7–13% in urban and 2–7% in rural areas[11] with Kerala showing a high prevalence of CAD (Coronary Arterial disease). Kerala also showed a high prevalence of risk factors (hypertension, 30%; Diabetes, 14.8%; smoking, 42%; abdominal obesity, 34%; low HDL, 36.9%; and hypertriglyceridemia, 19% with low awareness, especially on hypertension in a study done in 2010.[12] A similar study done in 2016 showed a mild increase in the prevalence of diabetes (15%) and an increase in abdominal obesity (57%).[13] In Tamil Nadu the recalibrated Framingham 10-year risk score (FRS) in males was 8.95 and 3.79 in females.[14] Whereas in the ICMR study, the cardiovascular risk among the urban population in India was 16–.5% in men and 15.3% in women according to the ICMR risk model.[15] Added to this, the death rate due to CVE (Cardiovascular events) in India was also found to increase from 15.2% in 1990 to 28.1% in 2012.[16] The high-risk score and the increasing death rate due to CVE entail a necessity to study the factors associated with it, Some of the classic modifiable risk factors for CVD in asymptomatic people above 40 years are hyperlipidemia, hypertension, diabetes, obesity, smoking, and lack of physical activity[17] and their combined risk could predict fatality using the Framingham’s equation.
The New Delhi Birth Cohort done between 1998 and 2006 among the young urban Indian population of a mean age of 29–36 years showed an increase in the prevalence of Obesity (52%–71% in men and from 48% to 70% in women), hypertension (11%–34% in men and from 5% to 15% in women) and Diabetes mellitus (5%–12% in men and from 3.5% to 7% in women). Triglyceride levels showed an increase but no increase in LDL was seen.[18] The reason for their rising prevalence rates has not been adequately investigated.
Could Vitamin D deficiency be an added risk factor independently or in association with other risk factors? During the past decades, studies have been done on the impact of vitamin D on cardiovascular disease (CVD) And most studies show that high CVD risk is associated with severe vitamin D deficiency. VDR (Vitamin D Receptors) and the 1α-hydroxylase are present in vascular tissues and also in cardiomyocytes where it has beneficial genomic effects, which include a reduction in thrombogenicity, vasoconstriction, oxidative stress, and atherogenesis may be the physiological basis of this association.[19] However studies like ViDA[20] in New Zealand and VITAL. In the US[21] done with supplementation shows no significant association between VDD and CV events including secondary effects like angina, heart failure hypertension, etc.
Studies with individual risk factors showed varied results.
Supplementation benefited T1DM[22] but not T2DM through a systemic review showed benefit among the non-obese and those with baseline VDD[23]
Similarly, it decreased Serum cholesterol, LDL (Low-Density lipoprotein), and Triglyceride levels (TG) but not HDL (High-Density Lipoprotein)[24] Subgroup analysis revealed that daily vitamin D3 therapy at a dose of >800 IU/day for <6 months in subjects ≥50 years old reduced both SBP and DBP (p < 0.001)[25] Whereas the latest studies show no effect of supplementation (<4000) on hypertension.[26]
As the various studies show contradictory results and as similar studies are not known to be done in Kerala, we aim to explore both the prevalence of Vitamin D deficiency and its association with cardiovascular risk factors. Understanding this association among apparently healthy subjects would give a more accurate physiological association between the two as the complications of the risk factors have not set in.
Materials and Methods
It was a cross-sectional study done among adults who came for a comprehensive health check over one month in 2014.
Inclusion criteria: All adults between 20 and 60 years who attended the executive health check of the hospital.
Exclusion Criteria: All those with any acute symptoms of the disease. All those known to suffer from complications of the risk factors like cardiovascular, renal, or retinal disease. All those above 60 years.
Individual data including waist circumference and blood pressure along with blood investigation like FBS, Triglycerides, and HDL was taken to look for obesity, hypertension, diabetes, and dyslipidemia.
FBS: Measured using the enzyme method.
Normal <110 mg%
Prediabetes ≥110 mg%
Diabetes ≥126 mg%[27]
HDL and Triglycerides were estimated by enzymatic method on an Olympus AU2700 analyzer.
Normal HDL ≤40 md/dl (men) or ≤50 mg/dl (women)
HDL A Risk: >40 mg/dl (men) or 50 mg/dl (women)[28]
Triglycerides[29]: Healthy: <150 milligrams per mg/dl
Borderline high: 150–199 mg/dl
High: 200–499 mg/dl
Abnormal TG/HDL ratio >2.5.
LDL, Total Cholesterol, and HbA1c were tested but not evaluated. TG/HDL ratio was linked to small dense LDL particles and has been recognized as a reliable risk marker of atherosclerotic cardiovascular disease.[30] FBS was more reliable to detect Diabetes than HbA1c and hence only evaluated.[31]
Waist Circumference[32]
| Waist circumference (cm)a | ||
|---|---|---|
| BMI category (kg/m2) | Women | Men |
| Normal weight (18.5–24.9) | ≥80 | ≥90 |
| Overweight (25–29.9) | ≥90 | ≥100 |
| Obese I (30–34.9) | ≥105 | ≥110 |
| Obese II and III (≥35) | ≥115 | ≥125 |
Obese 1 was considered as Obesity in this study
Hypertension[33]
| Blood Pressure Category | Systolic and Diastolic Pressure (mm Hg) |
|---|---|
| Normal | <120 (SBP)systolic pressure and <80 (DBP) diastolic pressure |
| Elevated | 120–129 mmHg SBP and <80 DBP mmHg |
| High Blood Pressure Stage 1 | 130–139 mmHg SBP or 80–89 mmHg DBP |
| High Blood Pressure Stage 2 | ≥140 SBP mmHg or 90 mmHg DBP |
High Blood pressure stage 2 was considered as hypertension in this study. Vitamin D: The quantitative estimation of 25-OHD3 is done using ARCHITECT 25-OH assay, which is a Chemiluminescent Micro-Particle Immune Assay (CMIA). The estimated vitamin D is a total of both vitamin D2 and vitamin D3.
Vitamin D deficiency can be classified as[34] Deficient < 20 ng/m
insufficient 20–29.9 ng/ml
Sufficient ≥30 ng/ml
Statistical analysis
Statistical analysis was performed using IBM SPSS version 20.0 software. Categorical variables were expressed as frequency and percentage. To test the statistical significance of the association of categorical variables with vitamin D deficiency, the Chi-square test was used.
Results
The total number of those studied among those who came for a comprehensive health checkup was 520.
Those who were above 40 years (68.4%) were much more than those who were below 40 years (31.6%). The mean age was 46 years.
The male population (64.8%) was much more than the female (33.2%) population.
This population of healthy adults shows a high prevalence of 86.9% (452) of those who are deficient and insufficient for Vitamin D.
81% of all males were found to be deficient whereas only 73.8% of all females. Male gender was associated (P=.04) with a higher prevalence of Vitamin D deficiency.
The most prevalent risk factor was hypertension (75%), followed by risk HDL (72.6%) and being overweight (60.5). Low vitamin D levels (Deficient and Insufficient) were associated with hypertension, diabetes, high TG, low HDL, TG/HDL ratio >2.5, and being overweight but not with obesity (P = 1.00).
There were no people in this study who had all four risk factors. Those who had DM and were obese were only 3 (3.4%).
Those having BP and being overweight (259) were most prevalent followed by BP and Diabetes Mellitus (77). Having more than one modifiable risk factor was also associated with vitamin D deficiency except when associated with Obesity. But being overweight along with other modifiable risk factors was associated with Vitamin D deficiency. Diabetes and dyslipidemia were significantly associated with vitamin D deficiency only at P < 0.1 even with hypertension
Discussion
Among those studied in the 3520, healthy adults who visited the health check in a tertiary centre in Kerala, the mean age was 46 years, 68.4% were above 40 years [Figure 1] and 64.8% were male [Figure 2]. Vitamin D deficiency tested in this population was 78.8% [Figure 3], which is on par with similar studies in India. A systematic review done by Aparna et al.[35] states that 40–99% of the people in India are deficient with most studies showing a range of 80–90. The cultural customs of decreased exposure to sunlight decreased intake of dairy and seafood, and the unavailability of fortified food may indicate a higher population of VDD. ‘Asian brown cloud, hot summers in India forcing people indoors, and dark pigmentation.[36] are other factors.
Figure 1.
Population according to age
Figure 2.
Population according to gender
Figure 3.
The prevalence of Vitamin D deficiency, Insufficiency and Sufficiency
In this study, more males (64.8%) than females had visited the hospital. And the prevalence of vitamin D deficiency (males 81%) was associated with the male gender (P = .04) [Table 1]. In a study in Italy, the female gender was associated with lower vitamin D levels (14.5 ± 10.9 vs. 15.9 ± 9.5, P = 0.007) whereas a study in Punjab showed that serum vitamin D was consistently lower in men (P < 0.02), irrespective of obesity and type 2 diabetes.[37] A higher group of those with low physical activity (65.8%) in Kerala and hence a lower exposure to sunlight could be the cause of the high prevalence among males in this study.[38]
Table 1.
The prevalence of Vitamin D deficiency according to Gender
| Vitamin D status | Male | Female | Total (n=520) | P |
|---|---|---|---|---|
| Vitamin D deficiency | 275 (81.6%) | 135 (73.8%) | 410 (78.8%) | 0.04 |
| Vitamin D insufficiency and sufficient | 62 (18.4%) | 48 (26.2%%) | 110 |
Vitamin D deficiency is highly prevalent in the elderly population above 65 years because of decreased sun exposure and decreased production by the skin[39] but that age group was not studied, In this study at the mean age of 46 years no association was seen (P = .364) [Table 2] indicating a uniform prevalence of VDD and hence a poor diet and exposure to sunlight.
Table 2.
Association of age to Vitamin D deficiency
| Vitamin D status | <46 yrs | >46 yrs | Total | P |
|---|---|---|---|---|
| Sufficient | 29 | 39 | 68 | P=0.364 |
| Vitamin D insufficiency and deficiency | 221 | 231 | 452 |
Age is not associated to Vitamin D deficiency
The classical modifiable risk factors for cardiovascular study are hypertension, diabetes, obesity, dyslipidemia, sedentary lifestyle, and smoking[40] but the latter two were not studied. The prevalence of these risk factors was hypertension (75%), Dyslipidaemia (TG, At risk HDL) (16.35%), diabetes (17%), obesity (1.1%), and overweight (60.5%) in this study [Table 2]. The prevalence of Cardiovascular risk factors for those above 46 years [Table 3] was hypertension, 83%; dyslipidemia, 11.9%; diabetes, 25.9%; and overweight, 60%. Age was associated with diabetes (p = <.001) and hypertension (p = <.001) but not with being overweight (P = .060), dyslipidemia (P = .034) and the high prevalence (61.2% of overweight and obese in this study of those less than 46 years is alarming and is similar to a rural study (56.5% in 40–49 yrs).[41]
Table 3.
Association of age to CVS risk factors
| CV Risk factors | <46 yrs (% with risk factor) | >46 yrs (% with risk factor) | P |
|---|---|---|---|
| Hypertension | 166 (66.4%) | 224 (83%) | P=<.001 |
| Diabetes | 20 (8%) | 69 (25.6% | P=<.001 |
| Dyslipidemia | 53 (21.2%) | 32 (11.9%) | P=0.034 |
| Overweight and obesity | 153 (61.2%) | 162 (60%) | P=0.060 |
Age was associated with diabetes and hypertension (P=<.001) but not with Dyslipidemia and being overweight/obese
According to the NFHS 5 data (National Family Health Survey), the prevalence of diabetes is higher in men (16.8%), in the age group 30-59 is 38.4% and 16.1% overall.[42] India ranks second in the prevalence of diabetics and is expected to increase from 74.9 million in 2021 to 124.9 million by 2045.[43] Kerala is known as the diabetic capital of India and more than 50% of household have at least one member who is diabetic according to the latest survey (NFHS -5). In this study, it was much more with 17.1% being diabetic and 28% prediabetes. The high carbohydrate diet, poor exercise habits and better economic status may indicate the reason.[44] Diabetes is known to cause microvascular and macrovascular complications. About 2/3 of those who are diabetic die of myocardial infarction.[45] Vitamin D deficiency may be a causative factor in the onset of diabetes as it contributes to both the initial insulin resistance, gene modulation, and an increase in inflammation.[46] Being diabetic was significantly associated with Vitamin D deficiency (p = <.001) [Table 4] in this study. The National Health and Nutrition Examination Survey (NHANES) III study demonstrated that there is a strong inverse association between low levels of 25 (OH)D and diabetes prevalence both by FBS (deficiency group (mean FBS 165.55 mg/dl) and insufficiency group (mean FBS 118.67 mg/dl) and HbA1c (deficiency group (8.06) and insufficiency group (7.23) (P value = 0.030).[47]
Table 4.
Association of Modifiable risk factors (Hypertension, Diabetes, Obesity and Dyslipidemia) to the Vitamin D status
| Sufficient (68) | Deficient and insufficient (452) | Total (520) | Chi-square | |
|---|---|---|---|---|
| Hypertension and vitamin d status | ||||
| Hypertension (≥140/90) | 27 (6.9%) | 363 (93.1%) | 390 (75%) | P=.<001 |
| No hypertension | 41 (31.5%) | 89 (68.5%) | 130 (25%) | |
| Obesity and vitamin d status | ||||
| Overweight and obese | 24 (7.6%) | 291 (92.4%) | 315 (60.5%) | P=<.001 |
| Normal | 44 (21.5%) | 161 (78.5%) | 205 (39.5%) | |
| Obese | 0 | 6 (100%) | 6 (1.1%) | P=1.000 |
| Non obese | 68 (13.2%) | 442 (86.8%) | 514 (98.8%) | |
| Diabetic status and vitamin d status | ||||
| Normal | 59 (20.7%) | 226 (79.3%) | 285 (54.8%) | P=<.001 |
| Prediabetic | 5 (3.4%) | 141 (96.6%) | 146 (28%) | |
| Diabetic | 4 (4.5%) | 85 (95.5%) | 89 (17%) | |
| Dyslipidemia and viamin d status | ||||
| TG ≥200 | 2 (2%) | 98 (98%) | 100 (19.2%) | P=<.001 |
| TG <200 | 66 (15,7%) | 354 (84.2%) | 420 (80.7%) | |
| Normal HDL | 44 (30.9%) | 98 (69%) | 142 (27.3%) | P=<.001 |
| At-RISK HDL | 24 (6.3%) | 354 (94.6%) | 378 (72.6%) | |
| Both TG >200 and At-Risk HDL | 1 (1.2%) | 84 (98.8%) | 85 (16.35) | P=<.001 |
| Neither >200 and At-Risk HDL | 67 (15.4%) | 368 (84.6%) | 435 (83.65) | |
| TG/HDL Ratio >2.5 | 22 (5.7%) | 364 (94.3%) | 386 (74.2%) | P=<.001 |
| TG/HDL Ratio ≤2.5 | 46 (34.3%) | 88 (65.7%) | 134 (25.8%) |
It has been found that around 48.4% of the US population is hypertensive (NHAES study 49.6%)[48] which is much higher than the urban Indian population (24-30%).[49] In Kerala, it was 43%,[50] which is almost on par with the US whereas in this study the prevalence among the healthy population was 75% [Table 4] which is the highest recorded. Increased consumption of salt-loaded fast food along with work stress may be the underlying reason. More readings would give better accuracy.[51]
Hypertension causes oxidative and metabolic stress making it a major risk factor for CVD[52] and its management is the cornerstone of cardiovascular risk reduction. The risk reduction to CVD was significantly associated with every 10 mm Hg reduction in systolic blood pressure.[53] Lifestyle modification is part of the plan for the treatment of elevated hypertension. Could low vitamin D be an added modifiable risk factor for hypertension? Here in this study, there was a strong association of hypertension to vitamin D deficiency (p = <.001) [Table 4]. Animal and human studies suggested low levels of 1,25 (OH)2D3 increase the activity of the RAAS (Renin Angiotensin Activating System), increase sympathetic activity, and decrease the Glomerular Filtration Rate. VDR receptors on the myocardium and vascular smooth muscles directly influence calcium influx, muscle relaxation, and diastolic function.[54] Further incidence of coronary calcification was associated with Low Vitamin D status.[55] Supplementation with vitamin D decreased SBP by 2.44 mmHg[56] and could prevent HTN among those with VDD if supplemented for five years and decrease BP among VD-deficient hypertensive patients by daily/weekly dose.[54]
Controlling Dyslipidaemia has decreased cardiac mortality by 18% and stroke mortality by 9%.[57] A total of 65% of the patients studied showed hypertriglyceridemia and 72.6% showed at-risk HDL [Table 4] levels, which is much higher than the India Heart Watch study (25.1% in males and 24.9% in females for hypercholesterolemia) and ICMR INDIAB (32% for hypertriglyceridemia).[58] Kerala (50.3%) followed by Goa (45.6%) and Himachal Pradesh (39,6%) were highly prevalent for hypercholesterolemia.[58] A diet rich in fat and carbohydrates and low in protein and fiber may contribute to this factor diet.[44] Though total cholesterol and LDL cholesterol an important parameters, it was not checked in this study as this data was primarily collected for the prevalence of metabolic syndrome but as increased triglycerides increase the formation of foam cells and are a predictor of atherosclerotic cardiovascular disease,[59] it was analyzed along with HDL values. In a study in Australia, a TG/HDL ratio > 2.5 was found to be independently associated with an increased risk of major adverse cardiovascular events (MACE).[60] In another study, the in Iran TG/HDL ratio and LDL/HDL ratio equally predicted cardiovascular risk in men but in women TG/HDL ratio was a better predictor[60] and is recognized as a risk factor for CVD by the National Cholesterol Education Program (NCEPIII).[61] In this study, 74.2% were found to have a TG/HDL ratio >2.5 [Table 4] again indicating an unbalanced improper diet.[44] Vitamin D affects lipid metabolism by gene expression, decrease in intracellular fat accumulation, and increased lipolysis and B oxidation of fatty acid thus lowering TG.[62] In a study among children, VDD was significantly associated with triglyceride levels (P = .003) level and TG/HDL ratio (P = 003) even among non-obese children,[63] and dyslipidemia among Indian adults (P = .0003).[64] Similarly, in this study, Hypertriglyceridemia, at-risk HDL, and TG/HDL >2.5 were associated with Vitamin D deficiency (p = <001) Shab-Bidar et al.,[65] in a study carried out in T2DM, found a decrease in LDL-C and TC along with a significant increase in HDL-C after vitamin D supplementation. Another study showed a decrease in TG levels and an increase in HDL with supplementation.[66]
Obesity/Overweight (BMI ≥25) is now a worldwide pandemic and is showing a rising trend in India. According to ICMR-INDIAB study in 2015, Being overweight increased from 11.8% to 31.3% from 1975 to 2015. Whereas in a multifactorial nationwide study in 2021, it was 40.3% with southern India at 46.51%.[67] This study being done on the health-conscious population showed obesity (BMI ≥30) prevalence was only 1.1% [Table 4]. Though those who were overweight were very high (60.5%). A similar study by Varghese et al.[68] in Kerala obese and overweight as 5.5% and 24.8%, respectively. The urban setting and the higher economic strata may be the cause for the higher prevalence of overweight obesity as was seen in a study among semi urban population in Kerala where 76.8% was found to be overweight and obese.[69] Though obesity was found only in 1.1% of the population, all of them were deficient but no significant association could be made (P = 1.000) [Table 4]. A bidirectional Mendelian study proved that obese people have a high incidence of VDD[68] as VD is found to be stored within fat cells[70] and therefore causes volume dilution VDD in obese people.[71] On the other hand, VDD is known to cause obesity by adipose differentiation and growth and therefore worsens the cardiovascular risk factor.[72] Though visceral obesity and inflammation are the core factors increasing the cardiovascular risk among the VD deficient no significant decrease in inflammatory markers was seen with supplementation[73] but a decrease in CRP was seen with 2 years of supplementation (VITAl randomized trial).[74]
Among those with multiple risk factors, hypertension and being overweight/obese were most prevalent (49.8%) [Table 5] and were associated with VDD (P ≥ 001). Only 3.8% had 3 risk factors). None had all 4 risk factors. Cardiovascular risk assessment could be done using the Framingham or ICMR model.[15]
Table 5.
Association of More Than Two Cardiovascular Risk Factors and Vitamin D
| Risk factors | Sufficient (68) | Deficient and insufficient (452) | Total (520) | Chi-square |
|---|---|---|---|---|
| BP and Dyslipidemia | 1 | 72 | 73 | P=<.001 |
| BP and DM | 3 | 74 | 77 | P=0.009 |
| BP, DM, Dyslipidemia | 0 | 20 | 20 | P=0.092 |
| BP, overweight, obese | 13 | 246 | 259 | P=<.001 |
| DM and Dyslipidemia | 0 | 22 | 22 | P=0.097 |
| Dyslipidemia and obese | 0 | 1 | 1 | P=1.000 |
| Overweight, obese, and dyslipidemia | 1 | 65 | 66 | P=<.001 |
| Total | 68 | 452 | 520 |
In addition to its action on cardiometabolic risk factors, recent studies have shown that vitamin D changes the gut microbiota composition by increasing the number of beneficial bacteria that help in glucose homeostasis, lipid metabolism, blood pressure, adiposity, vascular inflammation, and atherosclerosis.[75]
This study could make the primary healthcare worker more vigilant in detecting VDD and providing adequate supplementation. Early detection of cardiovascular risk factors and appropriate treatment measurements should be undertaken.[76] According to the IOM (Institute of Medicine) recommended intake of 600 IU daily is insufficient to reach sufficiency (30 ng/ml). A daily intake of 1000–4000 IU is recommended. Supplementation with calcium is recommended.[77] Intake of 11 μg/day (440 IU/day) from fortified foods (range, 120–1000 IU/day) increased 25 (OH)D concentrations in the blood by 7.7 ng/ml[77] and a similar increase was seen in Finland.[78] In many countries fish, livestock, and poultry have been fed with fortified food. Mushrooms and yeast have also been treated with UV light. In India fortification of stable food like wheat, and rice may be a feasible strategy and should be taken up on a national level.
Conclusion
The high prevalence of Vitamin D deficiency and the high prevalence of cardiovascular risk factors in this study with its strong association is proven though no underlying cause has been understood.
Decreasing the cost of Vitamin D testing and providing daily or weekly free supplementation is a necessity.
Health education regarding diet, exercise, and sun exposure should be provided in schools.
Policy change regarding fortification of food with Vitamin D especially dairy and staple food should be undertaken.
Limitations
Further studies with more readings on blood pressure per day, HbA1C, LDL, and total cholesterol would have strengthened this association. Cross-sectional study is not casual and hence a longitudinal study would be more informative. A similar study especially in the community could be done and compared as cardiovascular disease continues to be of concern both in the rural and urban. Studies proving the effect of supplementation, exercise, and sun exposure would be an added correlation.
Conflicts of interest
There are no conflicts of interest.
Funding Statement
Nil.
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