Vitamin D levels in seven non-identical occupational groups entail redefining of existing vitamin D deficiency diagnostic cut off level for native Bangladeshi population

Background and objectives: Recent publications have reported alarming prevalence of hypovitaminosis D in South Asian countries including Bangladesh. But, data on vitamin D levels in different occupational groups are lacking. This study addressed the prevalence of hypovitaminosis D in different occupational groups of Bangladesh. Additionally, the study estimated parathyroid hormone, phosphate, calcium and metabolic syndrome in these groups to see the effect of hypovitaminosis D on these parameters. Materials and method: Seven diverse occupational groups (agrarian workers, rickshaw-pullers, young cricketers and footballers, fishermen, dry fish industry workers, garment-workers and medical students) of Bangladesh were selected based on grade of physical activity and level of sun exposure. Blood was collected for the estimation of 25(OH) vitamin D, fasting glucose,lipid profiles, calcium, phosphate, magnesium and intact parathyroid (iPTH) hormone. Multiple comparisons of these variables among the 7 groups were estimated by ANOVA. Results: A total of 785 (m / f = 359 / 426) participants volunteered. Of them, 54.2% had vitamin D deficiency. Metabolic syndrome was 5% and showed no significant association with hypovitaminosis D (x2 = 0.9, p=0.43). For biophysical characteristics, the mean (±SD) values of age, body mass index, waist to hip ratio and waist to height ratio were – 33.8±16.3y, 22.3±4.1 kg/m2, 0.87±0.06 and 0.39±0.16, respectively. The values for vitamin D (ng/ml), calcium (mg/dl), iPTH (pgm/ml) and phosphate (mg/dl) were 20.25±13.1, 9.57±1.85, 38.22±24.54 and 4.18±0.81, respectively. The comparisons of vitamin D and other related variables among the groups (ANOVA) showed vitamin D level in the garments worker was significantly (p<0.01) higher from other 6 groups. Likewise, compared with other six, rickshaw-pullers had significantly higher calcium level. Calcium, phosphate and parathyroid hormone did not show any change with decreasing vitamin D level (high to low quartile: Q4→Q1), though parathyroid hormone increased significantly at the lowest vitamin D level (Q1:<11.8ng/ml: p=0.002). Conclusion: The prevalence of hypovitaminosis D was high irrespective of occupations, site (rural/urban), social class and sun-exposure. Overall, vitamin D level was low though varied among the groups. Despite minimum and maximum sun-exposure, the garments workers had the highest and the fishermen had the lowest vitamin D levels, respectively. Calcium level was normal in all groups. Calcium, phosphate and parathyroid hormone did not show any changes with decreasing vitamin D, though parathyroid hormone increased significantly when vitamin D decreased to the lowest quartile. The findings indicate that the specific cut off value for vitamin D deficiency needs to be determined for population of a given geographic area. IMC J Med Sci. 2023; 17(2):001. DOI: https://doi.org/10.55010/imcjms.17.011 *Correspondence: M Abu Sayeed, Department of Community Medicine, Ibrahim Medical College, 1/A, Ibrahim Sarani, Segunbagicha, Dhaka 1000, Bangladesh. Email: sayeed1950@gmail.com