MATERIALS AND METHODS

This was a Cross Sectional Study. The study protocol was approved by the institutional ethical committee for clinical research. Total 120 apparently healthy age-matched subjects were enrolled in the study. Written informed consent was taken from individual subjects. Anthropometric information, demographic characteristics, and biochemical data were obtained from the all study participants.

Inclusion Criteria: Age: 25-50 yrs, subjects of both male and female sex were included.

Exclusion Criteria: Pre-existing hypertension, cardiovascular diseases, diabetes mellitus, renal diseases, endocrine disorders, smoking, subjects on oral calcium and vitamin D supplementation, subjects with family history of obesity, postmenopausal women, pregnant females. Weight (in kilograms) was measured by an electronic weighing scale with subjects wearing light clothing and barefoot; height (in centimeters) was measured with each subject standing erect against wall without shoes with a wall-mounted ruler. Waist circumference (in centimeters) was measured at a point midway between the upper border of iliac crest and the lowest rib margin at the end of normal expiratory phase using a non-stretchable tape. Hip circumference (in centimeters) was measured by a tape at the widest point over the buttocks with no compression^6,10. Body Mass Index (BMI) was calculated as weight (kg)/height (m²).Waist: Hip ratio (W/H) was calculated. The study participants were classified into two groups, 60 non-obese, as controls and 60 obese as cases as indicated by body mass index categories (BMI <25 and BMI ≥30kg/m²) respectively based on WHO criteria^1,11. Venous blood samples were collected from all the participants and analyzed for serum calcium on fully-automated-analyzer. Serum calcium was estimated by the O- Cresolphthalein Complexone (OCPC) method.

Statistical Analysis: The results were analyzed by Graph pad prism software, version 5. Differences in demographic characteristics and biochemical parameters were statistically analyzed using Student’s t-test. Data were expressed as the mean ± standard deviation (SD). Pearson’s correlation coefficient was used to study the correlation among the study parameters. P value < 0.05 was considered statistically significant.

 

RESULTS

A description of the demographic characteristics of the study and the control groups is shown in Table 1. The obese individuals had signifi­cantly increased serum calcium levels compared with the non-obese controls (P < 0.05). (Table 2) Serum Calcium showed a significant positive correlation with BMI and W/H ratio. (Table 3) Table 4 shows the incidence of hypercalcemia in both the groups.

 

Table 1: Comparison of Demographic Characteristics in Obese and Non-obese Groups

Table 2: Comparison of Biochemical Parameters in Obese and Non-obese Groups

                                         

Table 3: Correlation of Serum Ca with BMI and W/H ratio in Obese Group

 

Table 4: Incidence of Hypercalcemia in Obese and Non-obese groups

 

 

DISCUSSION

Obesity is a complex, systemic, multi-causal problem, rooted in the sedentary nature of modern post-industrial life. Obesity has now been recognized as a global epidemic. Most alarmingly, the prevalence of obesity is on the rise among children and adolescents. That’s an especially worrisome trend, given the heavy burden of complications associated with the disease. At the other end of the malnutrition scale, obesity is one of today’s most blatantly visible – yet most neglected – public health problems. Paradoxically coexisting with under nutrition, an escalating global epidemic of overweight and obesity – “globesity” – is taking over many parts of the world. If immediate action is not taken, millions will suffer from an array of serious health disorders. In our study, we found that obese subjects have increased serum total calcium level as compared to that of non-obese controls. Serum calcium showed significant positive correlation with BMI and W/H ratio in obese participants. Various other studies supported the finding in our study. Omid Dalfardi et al¹⁰,Aktere N et al³, Xiao-hua Ren et al⁷, Shah P et al⁴ and Yang J et al¹² found increased serum calcium level in obese individuals. They also found the positive correlation of serum calcium with body mass index. However, N. A. A. Mohamed et al¹¹, EmelIpek et al¹³ did not find any significant difference in serum calcium level among obese and non-obese participants. Participants’ dietary habits might have contributed to the negative findings in these studies. The association of serum calcium with obesity is complex and much remains to be elucidated. Few plausible explanations for the mechanisms involved in this association are as follows. Obese individuals tend to have low basal vitamin D and high parathyroid hormone level than do non-obese individuals, which might be the result of obesity^1,4. This, in turn, elevates the calcium influx into a variety of cells including adipose tissues. Increased intracellular calcium increases the activity of fatty acid synthase and inhibits the expression of hormone-sensitive lipase, promoting lipogenesis and inhibiting lipolysis¹⁴.It also activates phosphodiesterase 3B, which subsequently reduces catecholamine-induced lipolysis. These effects, ultimately would promote lipid storage in fat tissue¹.In addition, intracellular calcium seems to have an effect on energy metabolism by affecting adipocyte apoptosis¹⁴. Obesity is thought to be a state of chronic, low-grade, systemic inflammation and is associated with increased oxidative stress. This leads to increased production of pro-inflammatory cytokines which stimulates increased osteoclastic activity and bone resorption; culminating in increased serum calcium levels¹⁰. So, from this study we can deduce that serum calcium level is significantly increased in obesity and is positively associated with BMI and W/H ratio. Thus, obesity might have influence on the calcium metabolism and increased calcium levels may also contribute to the causation of obesity. The role of daily calcium intake in the prevalence of obesity should be further investigated. Future studies are required to study the effects of vitamin D and parathyroid hormoneon serum calcium level in a large group of obese population.

Study Limitations: Smaller sample size, dietary calcium intake and lifestyle pattern of the participants was not taken into consideration.

 

CONCLUSION

In the present study, serum total calcium level was increased significantly in obese individuals than in non-obese individuals. Calcium showed significant positive correlation with anthropometric indices like BMI and W/H ratio among obese cases. This supports the hypothesis that mineral calcium may have an important role in the risk of developing obesity and obesity might affect the calcium metabolism leading to hypercalcemia. Obesity is now a critical global health issue, requiring a comprehensive intervention strategy rolled out at scale. New and more effective nutritional measures are urgently needed for the prevention of obesity.

 

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