Reference Interval of Vitamin D of Coastal Fishermen in Cox's Bazar District of Bangladesh

August 16, 2021 updated by: Wasim Md Mohosin Ul Haque, Bangladesh Institute of Research and Rehabilitation in Diabetes, Endocrine and Metabolic Disorders

The Level of Serum Vitamin D And Parathyroid Hormone Among Different Bangladeshi Population Groups

Lack of adequate sun exposure due to urbanization is prone to hypovitaminosis D. Vitamin D (25-hydroxyvitamin D) deficiency is now a major health concern in the western world. Recent data suggest that Vitamin D level in the Bangladeshi population is also very low. However, the cutoff value used to determine vitamin D deficiency is not yet validated for our ethnic group; we also don't know the optimal vitamin D level for our population. Before coming to any firm conclusion regarding nationwide vitamin D deficiency, we must know the Optimal range of serum Vitamin D for our people of Bangladesh. As sunlight is the primary source of vitamin D and adequate sun exposure alone is sufficient to produce enough vitamin D to maintain the physiological demand without producing toxicity. According to Holick's rule, exposure to sunlight at the face and both arms for 25 min, 3 times a week should maintain adequate vitamin D status. In Indonesia, it was found that after exposure to sunlight at this specific time and duration for 6 weeks, the mean 25(OH)D levels of participants increased from 59 nmol/L at the baseline to 84 nmol/L.In India, exposure to sunlight for 30 minutes, between 11 am and 2 pm, three times a week, is sufficient to maintain adequate serum vitamin D concentration. Therefore it could be assumed that healthy subjects without any risk factors for vitamin D deficiency and having adequate sun exposure should maintain an Optimal serum vitamin D concentration. Here Optimal means a range where there will be no features of insufficiency or toxicity. In this cross-sectional study, we want to find out the serum vitamin D level of such a population, representing the Optimal level of vitamin D for Bangladeshi people.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Vitamin D is the sunshine vitamin produced on this earth for more than 500 million years. This is produced in humans by sunlight. Sunlight is the main source of vitamin D, and adequate sun exposure alone is sufficient to produce enough vitamin D to maintain the physiological demand without producing toxicity. According to Holick's rule, exposure to sunlight on the face and both arms for 25 min, 3 times a week, should maintain adequate vitamin D status. In Indonesia, it was found that after exposure to sunlight at this specific time and duration for 6 weeks, the mean 25(OH)D levels of participants increased from 59 nmol/L at the baseline to 84 nmol/L.In India, exposure to sunlight for 30 minutes, between 11 am and 2 pm, three times a week is sufficient to maintain adequate serum vitamin D concentration. Lack of adequate sun exposure as a consequence of urbanization prone human races to a threat of hypovitaminosis D. Vitamin D (25-hydroxyvitamin D) insufficiency and its impending consequence on health is now the subject of important concern and controversy. The optimal value of vitamin D substantially differs among populations depending upon environmental, cultural and racial factors. However, the definition of vitamin D insufficiency is still not out of controversy, mostly cutoffs of <50 nmol/L of serum 25-hydroxyvitamin D (25(OH)D) level is considered as "vitamin D deficiency" state, 50 to 74.9 nmol/L denotes "insufficiency" and ≥75 nmol/L considered as "sufficiency".

With the falling of serum25 (OH)D beyond a certain point, absorption of calcium from the gut decreases, which leads to a surge of parathyroid hormone (PTH) secretion, which in turn stimulates the conversion of 25(OH)D to 1,25(OH)2D to keep calcium at a normal limit. Thus, a higher value of PTH could be considered as a surrogate marker of vitamin D insufficiency. Serum 25(OH) D below the level of 75-100 nmol/L has an inverse correlation with PTH concentration; beyond this point, serum intact PTH concentration remains in a plateau state.

Based on these definitions, the whole world faces a pandemic of vitamin D deficiency/insufficiency. According to recent studies, the prevalence of vitamin D deficiency has been found between 30% and 100% in different communities. This picture is similar in the USA, Europe, South East Asia and the Middle East. In India, the prevalence of Vitamin D deficiency is around 70%-100% in the general population. Baidya et al. (2012) studied 40 healthy Indian physicians in Calcutta. Around 97.5% of subjects had low vitamin D. Mean age and meant 25(OH)D levels of that cohort were 52.22 ± 10 years and 13.02 ± 4.77 ng/ml (32.50±11.91 nmol/L). Vitamin D deficiency was found in 92.5% of participants. Though available data in Bangladesh are confined to female subjects only, the scenario is not different. More than ninety-nine percent of Bangladesh female garment workers were vitamin D insufficient in a study.

This picture is alarming because, in addition to its deleterious effect on the musculoskeletal system, vitamin D deficiency is also linked with many other medical issues like cardiovascular disease, malignancy, neuromodulation, diabetes, and metabolic syndrome several autoimmune diseases (such as multiple sclerosis, Crohn's disease and ulcerative colitis) and certain infectious diseases, such as tuberculosis. Vitamin D supplementation is also a key component in the hierarchy of management of Chronic Kidney Disease-Mineral and Bone Disorder.

However, the caveat of all of those studies done in Bangladesh and neighbouring countries like India and Pakistan is that the cutoff value used to determine vitamin D deficiency or insufficiency has not yet been validated for the corresponding population. Before reaching a firm conclusion about epidemics of vitamin D deficiency and planning for supplementation programs, the cutoff value of vitamin D deficiency/insufficiency of the Bangladeshi population must be validated. The optimal level of vitamin D for the Bangladeshi population should also find out.

Rationale: Maintenance of adequate vitamin D levels undoubtedly is an important human health issue. It helps prevent many chronic diseases, which in fact are in addition to its principal role in maintaining appropriate blood calcium levels. To get the optimum beneficial effects of vitamin D, including prevention of many potential adverse health effects caused by deficient vitamin D, circulating 25(OH)D levels should be within the normal range. Vitamin D varies depending on various factors like exposure to the sun, age, race, body mass index, lack of exercise etc. The cutoff value for deficiency and insufficiency also varies between studies. Several studies using prescribed cutoff values of vitamin D deficiency reveal an epidemic of vitamin D deficiency in our country, despite abounded sunlight due to the proximity of the equator. However, no study was done previously in Bangladesh to determine the Optimal value of vitamin D representative of this population. The deficiency and insufficiency levels are ignorant and when to intervene is also not known. That is why it is important to conduct this exploratory study. It will help to assume the optimal reference range of serum vitamin D for the Bangladeshi population. That will give a clearer picture of the actual burden of vitamin D deficiency in Bangladesh and guide them to treat them and take necessary preventive measures at the national level.

Study Type

Observational

Enrollment (Actual)

556

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Bangladesh
      • Cox's Bazar, Bangladesh, 4700
        • Cox's Bazar
      • Dhaka, Bangladesh, 1000
        • BIRDEM General Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

16 years to 63 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Adequately sun-exposed healthy population: Healthy fishermen with at least 30 minutes of sun exposure between 11 am and 2 pm, three times a week for the preceding 6 months.

All male aged 18 to 65 years

Inadequately sun-exposed healthy population: Urban, office-based workers or homemakers, both male and female, who will come for a routine health check-up in the BIRDEM outpatient department, and health care workers of selected hospitals of Dhaka. Both male and female aged 18 to 65 years.

Description

Inclusion Criteria:

  • Healthy fishermen
  • Healthy health care workers
  • Who will be willing to participate in the study

Exclusion Criteria:

  • Those who will refuse to participate in the interview
  • Physically and psychologically handicapped
  • Subjects with known chronic illnesses like liver, kidney or gastrointestinal disease, metabolic bone disease, malignancy, pregnancy and lactation, history of immobility for more than 1 week, on vitamin D or calcium supplementation, on anti-epileptic drugs
  • Primary hyperparathyroidism
  • Subject having lactose intolerance

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: Ecologic or Community
  • Time Perspectives: Cross-Sectional

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Adequately sun-exposed healthy population
Healthy coastal fishermen of Cox's Bazar district of Bangladesh
Diagnostic test: Serum vitamin D assay

Trained phlebotomists will collect 10 cc of a Blood sample. Specimen will be preserved at -40ºc for batch analysis.

S Vitamin D, S iPTH, S Calcium, S Alkaline Phosphatase, S PO4, S Mg, S Albumin and S Creatinine will be done in BIRDEM laboratory. Vitamin D will be assayed by The ARCHITECT 25-OH Vitamin D assay system: Vitamin D will be assayed by The ARCHITECT 25-OH Vitamin D assay system: The ARCHITECT 25-OH Vitamin D assay is a chemiluminescent micro-particle immunoassay (CMIA). This technology is used for the quantitative analysis of 25(OH) D and aid in the assessment of vitamin D sufficiency.

Other Names:
  • Serum iPTH assay
Inadequately sun-exposed healthy population
Healthcare workers of the selected hospitals of Dhaka, Bangladesh
Diagnostic test: Serum vitamin D assay

Trained phlebotomists will collect 10 cc of a Blood sample. Specimen will be preserved at -40ºc for batch analysis.

S Vitamin D, S iPTH, S Calcium, S Alkaline Phosphatase, S PO4, S Mg, S Albumin and S Creatinine will be done in BIRDEM laboratory. Vitamin D will be assayed by The ARCHITECT 25-OH Vitamin D assay system: Vitamin D will be assayed by The ARCHITECT 25-OH Vitamin D assay system: The ARCHITECT 25-OH Vitamin D assay is a chemiluminescent micro-particle immunoassay (CMIA). This technology is used for the quantitative analysis of 25(OH) D and aid in the assessment of vitamin D sufficiency.

Other Names:
  • Serum iPTH assay

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Serum vitamin D levels
Time Frame: Day 1
Serum vitamin D levels of healthy fishermen, healthy volunteers and healthy healthcare workers will be measured in the chemiluminescent microparticle immunoassay method.
Day 1

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Serum parathyroid hormone levels
Time Frame: Day 1
Serum parathyroid hormone levels of healthy fishermen, healthy volunteers and healthy healthcare workers will be measured in the chemiluminescent microparticle immunoassay method.
Day 1

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Bangladesh Institute of Research and Rehabilitation in Diabetes, Endocrine and Metabolic Disorders

Collaborators

Bangladesh Medical Research Council (BMRC)

Investigators

  • Principal Investigator: Wasim Md Mohosin Ul Haque, FCPS, BIRDEM General Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 1, 2017

Primary Completion (Actual)

August 15, 2021

Study Completion (Actual)

August 15, 2021

Study Registration Dates

First Submitted

May 26, 2021

First Submitted That Met QC Criteria

July 30, 2021

First Posted (Actual)

August 2, 2021

Study Record Updates

Last Update Posted (Actual)

August 17, 2021

Last Update Submitted That Met QC Criteria

August 16, 2021

Last Verified

August 1, 2021

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • BADAS-ERC/EC/21/00310

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

No

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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